CN117440356A

CN117440356A - Communication method and device

Info

Publication number: CN117440356A
Application number: CN202210822414.7A
Authority: CN
Inventors: 陈泽昊; 李永翠; 倪慧
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-07-13
Filing date: 2022-07-13
Publication date: 2024-01-23
Also published as: WO2024012230A1

Abstract

The application provides a communication method and a communication device, which belong to the technical field of communication and are used for realizing that a terminal accessing a home network can still access services deployed in other operator networks. In the method, under the condition that the first service is deployed in the second network and the terminal accesses the home network, the access and mobility management network element of the home network can select a second session management network element in the second network for the first service based on the slice identifier associated with the first service, so that the second session management network element can establish a session of the first service for the terminal, for example, a session anchor point of the first service in the second network, for example, a protocol data unit session anchor point PSA is selected, so that the terminal can access the first service through the PSA, and the terminal accessing the home network can still access the service deployed in other operator networks.

Description

Communication method and device

Technical Field

The present disclosure relates to the field of communications, and in particular, to a communication method and apparatus.

Background

Currently, edge Computing (EC) traffic tends to have high latency requirements, and thus requires a more densely deployed multi-access edge computing (MEC) platform. However, in practical deployment, it is difficult to implement deployment by a single operator or a third party due to cost and other restrictions. One reasonable way is for multiple operators (or third parties) to co-deploy the MEC platform, the edge support environment (edge hosting environment, EHE). That is, a particular functional MEC platform, or a particular service, may be deployed by different operators at different locations, or the service may be deployed on only a portion of the operators deployed MEC platforms, or the MEC platform may be deployed by only a portion of the operators.

In the deployment mode described above, it is assumed that the public land mobile network (public land mobile network, PLMN) of operator a and the PLMN of operator B are deployed at the location of the terminal, and the terminal is affiliated with operator a. Service X is deployed on the MEC platform of operator B. Wherein the MEC platform of operator B does not support protocol data unit session anchor (protocol data unit session anchor, PSA) access of operator a, and either service X is not deployed at the MEC platform of operator a or the MEC platform is not deployed by operator a. At this time, when the terminal requests access to the service X, the access of the terminal to the service X may be limited because the MEC platform of the operator B does not support PSA access of the operator a.

Disclosure of Invention

The embodiment of the application provides a communication method and a communication device, which are used for realizing that a terminal accessing a home network can still access services deployed in other operator networks.

In order to achieve the above purpose, the present application adopts the following technical scheme:

in a first aspect, a communication method is provided. The method comprises the following steps: the access and mobility management network element receives a session establishment request message from the terminal. The access and mobility management network element is deployed in a first network, the first network is a home network of a terminal, and the terminal accesses the home network. The session establishment request message includes a slice identity associated with a first service deployed by a second network, the second network being a network other than the home network. In this way, the access and mobility management network element determines, according to the slice identifier, a second session management network element in the second network, where the second session management network element is configured to establish a session for the terminal for accessing the first service.

Based on the above method, in the case that the first service is deployed in the second network and the terminal accesses the home network, the access and mobility management network element of the home network can select a second session management network element in the second network for the first service based on the slice identifier associated with the first service, so that the second session management network element can establish a session of the first service for the terminal, for example, select a session anchor point of the first service in the second network, for example, a protocol data unit session anchor PSA, so that the terminal can access the first service through the PSA, and the terminal accessing the home network can still access the service deployed in other operator networks.

In one possible design, the slice identifier associated with the first service is a first slice identifier of the first service in the home network, and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, including: the access and mobility management network element determines a second session management network element in the second network according to the first slice identifier of the first service in the home network, so that the second session management network element can be ensured to support the slice corresponding to the first service.

Optionally, the access and mobility management network element determines a second session management network element according to the first slice identifier, including: the access and mobility management network element determines a second slice identifier of the first service in the second network and an identifier of the second network according to the first slice identifier, and determines a second session management network element according to the second slice identifier and the identifier of the second network. It will be appreciated that since the slice identity of a service in other networks (networks other than the first and second networks) may be the same as the second slice identity, i.e. the second slice identity is a non-unique identity, the access and mobility management network element may use the identity of the second network to distinguish between these same slice identities to ensure that a second session management network element within the second network can be selected instead of the session management network elements of the other networks.

Further, the access and mobility management network element determines a second slice identifier of the first service in the second network and an identifier of the second network according to the first slice identifier, including: and the access and mobility management network element determines a second slice identifier and an identifier of a second network according to the first slice identifier and the association relation. The association relationship is an association relationship of a first slice identifier, a second slice identifier and an identifier of a second network, and is used for conveniently determining the second slice identifier associated with the first slice identifier and the identifier of the second network.

Optionally, the access and mobility management network element determines a second session management network element according to the first slice identifier, including: the access and mobility management network element determines a second slice identifier of the first service in the second network according to the first slice identifier, and determines a second session management network element according to the second slice identifier. It will be appreciated that if the slice identity of no service in the other networks (networks other than the first network and the second network) is the same as the second slice identity, i.e. the second identity is a unique identity, then the access and mobility management network element may not take into account the identity of the second network when selecting the second session management network element, so that the processing logic is simpler.

Further, the access and mobility management network element determines a second slice identifier of the first service in the second network according to the first slice identifier, including: the access and mobility management network element determines a second slice identifier according to the first slice identifier and an association relationship, wherein the association relationship is that of the first slice identifier and the second slice identifier, so as to conveniently determine the second slice identifier associated with the first slice identifier.

Optionally, before the access and mobility management network element determines the second session management network element according to the first slice identifier, the method of the first aspect may further include: the access and mobility management network element determines that the first slice list contains a first slice identifier. Wherein the slice identifier in the first slice list is a slice identifier of the service deployed by the second network in the home network. In other words, the access and mobility management network element may determine that the slice identity is the slice identity of traffic deployed in the other network mapped to the home network in order to properly select session management network elements located within the other network.

Optionally, the method of the first aspect may further include: the access and mobility management network element determines a first session management network element within the home network based on the first slice identity, the first session management network element being operable to establish a user plane connection of the terminal to a PSA of the second network, ensuring that the terminal can access the first service through the PSA.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect may further include: the access and mobility management network element sends the first slice identifier to the terminal so as to ensure that the terminal can feed back the first slice identifier subsequently.

Further, the first slice identifier sent by the access and mobility management network element to the terminal may be carried in the routing policy urs of the terminal, that is, carried in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

In one possible design, the slice identifier associated with the first service is a second slice identifier of the first service in the second network, and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, including: the access and mobility management network element determines a second session management network element according to the second slice identifier and the identifier of the second network. That is, since the slice identity of a certain service in other networks (networks other than the first network and the second network) may be identical to the second slice identity, the access and mobility management network element may use the identity of the second network to distinguish these identical slice identities to ensure that a second session management network element within the second network can be selected instead of the session management network elements of the other networks.

In one possible design, the slice identifier associated with the first service is a second slice identifier of the first service in the second network, and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, including: and the access and mobility management network element determines a second session management network element according to the second slice identifier. That is, if the second slice identity is a unique identity, the access and mobility management network element may not take into account the identity of the second network when selecting the second session management network element, so that the processing logic is simpler.

Optionally, before the access and mobility management network element determines the second session management network element, the method of the first aspect further includes: the access and mobility management network element determines that the second slice list contains a second slice identifier. Wherein the slice identifier in the second slice list is a slice identifier of the service deployed by the second network within the second network. In other words, the access and mobility management network element may determine that the slice identifier is a slice identifier of traffic deployed in the other network in order to properly select a session management network element located in the other network.

Optionally, the method of the first aspect further comprises: the access and mobility management network element determines a first session management network element within the home network according to the second slice identity, the first session management network element being operable to establish a user plane connection of the terminal to a PSA of the second network, ensuring that the terminal can access the first service through the PSA.

Further, the access and mobility management network element determines a first session management network element in the home network according to the second slice identifier, including: the access and mobility management network element determines a first slice identifier of the first service in the home network according to the second slice identifier and the identifier of the second network, thereby determining the first session management network element according to the first slice identifier. That is, if the second slice identity is a non-unique identity, the access and mobility management network element may use the identity of the second network to distinguish between these same slice identities to ensure that the first slice identity can ultimately be determined, but not the slice identities of the other networks.

Further, the access and mobility management network element determines a first slice identifier of the first service in the home network according to the second slice identifier and the identifier of the second network, including: the access and mobility management network element determines a first slice identifier according to the second slice identifier, the identifier of the second network and the association relation. The association relationship is an association relationship of a first slice identifier, a second slice identifier and an identifier of a second network, and is used for conveniently determining the first slice identifier associated with the second slice identifier and the identifier of the second network.

Further, the access and mobility management network element determines a first session management network element in the home network according to the second slice identifier, including: the access and mobility management network element determines a first slice identifier of the first service in the home network according to the second slice identifier, thereby determining the first session management network element according to the first slice identifier. That is, if the second slice identity is a unique identity, the access and mobility management network element may not consider the identity of the second network when determining the first slice identity, and processing logic may be simplified.

Further, the access and mobility management network element determines a first slice identifier of the first service in the home network according to the second slice identifier, including: and the access and mobility management network element determines the first slice identifier according to the second slice identifier and the association relation. The association relationship is an association relationship between the first slice identifier and the second slice identifier, and is used for conveniently determining the first slice identifier associated with the second slice identifier.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect further comprises: the access and mobility management network element sends the second slice identifier to the terminal so as to ensure that the terminal can feed back the second slice identifier subsequently.

Further, the second slice identifier sent by the access and mobility management network element to the terminal may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce complexity of implementing the scheme, or may also be carried in a new cell, so as to improve flexibility of implementing the scheme, without limitation.

In one possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, including: the access and mobility management network element determines a first session management network element within the home network based on the first slice identifier and determines a second session management network element based on the second slice identifier and the identifier of the second network. Wherein the second session management network element is operable to select a PSA of the first service on the second network, the first session management network element being operable to establish a user plane connection of the terminal to the PSA to ensure that the terminal can access the first service through the PSA.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect further comprises: the access and mobility management network element sends the association relation, the first slice identifier and the identifier of the second network to the terminal. The association relationship is that of a first slice identifier, a second slice identifier and a second network identifier. Therefore, the process of determining the second slice identifier by the terminal can be realized, for example, the terminal determines the second slice identifier according to the association relation, the first slice identifier and the identifier of the second network, thereby simplifying the realization complexity of the access and mobility management network element and reducing the cost of the network side.

Further, the first slice identifier and the identifier of the second network sent by the access and mobility management network element to the terminal may be carried in the urs of the terminal, that is, carried in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect further comprises: the access and mobility management network element sends the association relation, the second slice identifier and the identifier of the second network to the terminal. The association relationship is that of a first slice identifier, a second slice identifier and a second network identifier. Therefore, the process of determining the first slice identifier by the terminal can be realized, for example, the terminal determines the first slice identifier according to the association relation, the second slice identifier and the identifier of the second network, thereby simplifying the realization complexity of the access and mobility management network element and reducing the cost of the network side.

Further, the second slice identifier and the identifier of the second network sent by the access and mobility management network element to the terminal may be carried in the urs of the terminal, that is, carried in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

In one possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, including: the access and mobility management network element determines a first session management network element within the home network based on the first slice identifier and a second session management network element based on the second slice identifier. That is, if the second slice identity is a unique identity, the access and mobility management network element may not take into account the identity of the second network when determining the second session management network element, so that the processing logic is simpler.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect further comprises: the access and mobility management network element sends an association relation and a first slice identifier to the terminal. The association relationship is the association relationship of the first slice identifier and the second slice identifier. That is, if the second slice identifier is a unique identifier, the access and mobility management network element may not provide an association relationship between the network and the slice identifier, so as to save overhead and improve communication efficiency.

Further, the first slice identifier sent by the access and mobility management network element to the terminal may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

Optionally, before the access and mobility management network element receives the session establishment request message from the terminal, the method of the first aspect further comprises: the access and mobility management network element sends the association relation and the second slice identifier to the terminal. The association relationship is the association relationship of the first slice identifier and the second slice identifier. That is, if the second slice identifier is a unique identifier, the access and mobility management network element may not provide an association relationship between the network and the slice identifier, so as to save overhead and improve communication efficiency.

Further, the second slice identifier sent by the access and mobility management network element to the terminal may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

Optionally, the method of the first aspect further comprises: the access and mobility management network element may obtain the association relationship from the policy control network element or the network slice selection network element, or may also obtain the association relationship from any other possible network element, without limitation.

In one possible design, the first service is a service that needs to be accessed through a session anchor point of the second network, so that it can be further realized that in a case where the service does not support PSA access of other operators, the other operators, such as a terminal of the home network, can still access the service.

In a second aspect, a communication method is provided. The method comprises the following steps: the terminal sends a session establishment request message to the access and mobility management network element. The access and mobility management network element is deployed in a first network, the first network is a home network of a terminal, the terminal accesses the home network, the session establishment request message comprises a slice identifier associated with a first service deployed in a second network, and the second network is a network except the home network. In this way, the terminal receives a session establishment acceptance message from the access and mobility management network element, wherein the session establishment acceptance message is used to indicate that the second network has established a session for the terminal for accessing the first service.

In a possible design, the slice identifier associated with the first service is a first slice identifier of the first service in the home network, and before the terminal sends the session establishment request message to the access and mobility management network element, the method in the second aspect further includes: the terminal receives a first slice identifier from an access and mobility management network element.

Optionally, the first slice identifier received by the terminal from the access and mobility management network element is carried in a urs p of the terminal.

In a possible design, the slice identifier associated with the first service is a second slice identifier of the first service in the second network, and before the terminal sends the session establishment request message to the access and mobility management network element, the method in the second aspect further includes: the terminal receives a second slice identifier from the access and mobility management network element.

Optionally, the second slice identifier received by the terminal from the access and mobility management network element is carried in a urs p of the terminal.

In a possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, where before the terminal sends the session establishment request message to the access and mobility management network element, the method of the second aspect further includes: the terminal may determine the second slice identifier according to the first slice identifier, the identifier of the second network, and the association relationship. The association relationship is the association relationship of the first slice identifier, the second slice identifier and the identifier of the second network.

Optionally, before the terminal determines the second slice identifier according to the first slice identifier, the identifier of the second network, and the association relationship, the method of the second aspect further includes: the terminal receives an association relation between access and a mobility management network element, a first slice identifier and an identifier of a second network.

It can be seen that since the slice identity of a service in other networks (networks other than the first network and the second network) may be the same as the second slice identity, i.e. the second slice identity is a non-unique identity, the access and mobility management network element may provide the terminal with the identity of the second network to distinguish these same slice identities, to ensure that the terminal is eventually able to determine the second slice identity instead of the slice identities of the other networks.

Optionally, the first slice identifier and the identifier of the second network received by the terminal from the access and mobility management network element are carried in a urs p of the terminal.

In a possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, where before the terminal sends the session establishment request message to the access and mobility management network element, the method of the second aspect further includes: the terminal may determine the second slice identifier based on the first slice identifier and the identifier of the second network. The association relationship is the association relationship of the first slice identifier, the second slice identifier and the identifier of the second network.

Optionally, before the terminal determines the second slice identifier according to the first slice identifier and the identifier of the second network, the method of the second aspect further includes: the terminal receives an association relation from an access and a mobility management network element and a first slice identifier.

It can be seen that if the slice identity of no service in the other network (network other than the first network and the second network) is the same as the second slice identity, i.e. the second slice identity is a unique identity, the access and mobility management network element may not provide an association between the network and the slice identity, so that the terminal may not consider the identity of the second network when determining the second slice identity, and thus the processing logic is simpler.

In a possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, where before the terminal sends the session establishment request message to the access and mobility management network element, the method of the second aspect further includes: the terminal may determine the first slice identifier according to the second slice identifier, the identifier of the second network, and the association relationship. The association relationship is the association relationship of the first slice identifier, the second slice identifier and the identifier of the second network.

Optionally, before the terminal determines the first slice identifier according to the second slice identifier, the identifier of the second network, and the association relationship, the method of the second aspect further includes: the terminal receives the association relation between the access and the mobility management network element, the second slice identifier and the identifier of the second network.

Optionally, the second slice identifier and the identifier of the second network received by the terminal from the access and mobility management network element are carried in a urs p of the terminal.

It can be seen that since the slice identity of a service in other networks (networks other than the first network and the second network) may be the same as the second slice identity, i.e. the second slice identity is a non-unique identity, the access and mobility management network element may provide the terminal with the identity of the second network to distinguish these same slice identities, to ensure that the terminal is eventually able to determine the first slice identity but not the slice identities of the other networks.

In a possible design, the slice identifier associated with the first service includes a first slice identifier of the first service in the home network and a second slice identifier of the first service in the second network, where before the terminal sends the session establishment request message to the access and mobility management network element, the method of the second aspect further includes: the terminal can determine the first slice identifier according to the second slice identifier and the association relation. The association relationship is a first slice identifier and a second slice identifier.

Optionally, before the terminal determines the first slice identifier according to the second slice identifier and the association relationship, the method of the second aspect further includes: the terminal receives the association relation from the access and mobility management network element and the second slice identifier, optionally, the second slice identifier received by the terminal from the access and mobility management network element is carried in the urs of the terminal.

It can be seen that if the slice identity of no service in the other network (network other than the first network and the second network) is the same as the second slice identity, i.e. the second slice identity is a unique identity, the access and mobility management network element may not provide an association between the network and the slice identity, so that the terminal may not consider the identity of the first network when determining the first slice identity, and thus the processing logic is simpler.

Further, the other technical effects of the communication method described in the second aspect may refer to the technical effects of the communication method described in the first aspect, and are not described herein.

In a third aspect, a communication device is provided. The apparatus comprises means, e.g. a transceiver module and a processing module, for performing the method of the first aspect described above. Wherein, the transceiver module can be used for realizing the function of the device for receiving and sending messages. The processing module may be used to implement functions of the device other than messaging.

Alternatively, the transceiver module may include a transmitting module and a receiving module. Wherein, the sending module is used for realizing the sending function of the communication device according to the third aspect, and the receiving module is used for realizing the receiving function of the communication device according to the third aspect.

Optionally, the communication device according to the third aspect may further include a storage module, where the storage module stores a program or instructions. The processing module, when executing the program or instructions, enables the communication device to perform the communication method of the first aspect.

It should be noted that the communication apparatus according to the third aspect may be a network device, such as the first network element, or may be a chip (system) or other components or assemblies that may be disposed in the network device, or may be an apparatus including the network device, which is not limited in this application.

Further, the technical effects of the communication apparatus according to the third aspect may refer to the technical effects of the communication method according to the first aspect, and will not be described herein.

In a fourth aspect, a communication device is provided. The apparatus comprises means, e.g. a transceiver module and a processing module, for performing the method of the second aspect described above. Wherein, the transceiver module can be used for realizing the function of the device for receiving and sending messages. The processing module may be used to implement functions of the device other than messaging.

Alternatively, the transceiver module may include a transmitting module and a receiving module. The sending module is used for realizing the sending function of the communication device according to the fourth aspect, and the receiving module is used for realizing the receiving function of the communication device according to the fourth aspect.

Optionally, the communication device according to the fourth aspect may further include a storage module, where the storage module stores a program or instructions. The processing module, when executing the program or instructions, causes the communication device to perform the communication method described in the second aspect.

Note that, the communication apparatus according to the fourth aspect may be a network device, such as an application function, or may be a chip (system) or other components or assemblies that may be disposed in the network device, or may be an apparatus including the network device, which is not limited in this application.

Further, the technical effects of the communication apparatus according to the fourth aspect may refer to the technical effects of the communication method according to the second aspect, and will not be described herein.

In a fifth aspect, a communication device is provided. The communication device includes: a processor configured to perform the communication method of the first or second aspect.

In one possible configuration, the communication device according to the fifth aspect may further comprise a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be for use in a communication device according to the fifth aspect to communicate with other communication devices.

In one possible configuration, the communication device according to the fifth aspect may further comprise a memory. The memory may be integral with the processor or may be separate. The memory may be used for storing computer programs and/or data related to the communication method according to the first or second aspect.

In the present application, the communication apparatus according to the fifth aspect may be a network device, or a chip (system) or other parts or components that may be disposed in the network device, or an apparatus including the network device.

Further, the technical effects of the communication apparatus according to the fifth aspect may refer to the technical effects of the communication method according to the first aspect or the second aspect, and are not described herein.

In a sixth aspect, a communication device is provided. The communication device includes: a processor coupled to the memory, the processor for executing the computer program stored in the memory to cause the communication device to perform the communication method described in the first or second aspect.

In one possible configuration, the communication device according to the sixth aspect may further comprise a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be for use in a communication device according to the sixth aspect to communicate with other communication devices.

In this application, the communication apparatus according to the sixth aspect may be a network device, or a chip (system) or other part or component that may be provided in the network device, or an apparatus including the network device.

Further, the technical effects of the communication apparatus according to the sixth aspect may refer to the technical effects of the communication method according to the first aspect or the second aspect, and will not be described herein.

In a seventh aspect, there is provided a communication apparatus comprising: a processor and a memory; the memory is configured to store a computer program which, when executed by the processor, causes the communication device to perform the communication method of the first or second aspect.

In one possible configuration, the communication device according to the seventh aspect may further comprise a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be for use in a communication device according to the seventh aspect to communicate with other communication devices.

In this application, the communication apparatus according to the seventh aspect may be a network device, or a chip (system) or other part or component that may be disposed in the network device, or an apparatus including the network device.

Further, the technical effects of the communication apparatus according to the seventh aspect may refer to the technical effects of the communication method according to the first aspect or the second aspect, and will not be described herein.

An eighth aspect provides a communication apparatus comprising: a processor; the processor is configured to execute the communication method according to the first or second aspect according to the computer program after being coupled to the memory and reading the computer program in the memory.

In one possible configuration, the communication device according to the eighth aspect may further comprise a transceiver. The transceiver may be a transceiver circuit or an interface circuit. The transceiver may be for use in a communication device according to the eighth aspect to communicate with other communication devices.

In the present application, the communication apparatus according to the eighth aspect may be a network device, or a chip (system) or other parts or components that may be disposed in the network device, or an apparatus including the network device.

Further, the technical effects of the communication apparatus according to the eighth aspect may refer to the technical effects of the communication method according to the first aspect or the second aspect, and will not be described herein.

In a ninth aspect, a communication system is provided. The communication system comprises a first network element according to the first aspect and/or an application function according to the second aspect.

In a tenth aspect, there is provided a computer readable storage medium comprising: computer programs or instructions; the computer program or instructions, when run on a computer, cause the computer to perform the communication method of the first or second aspect.

In an eleventh aspect, there is provided a computer program product comprising a computer program or instructions which, when run on a computer, cause the computer to perform the communication method of the first or second aspect.

Drawings

FIG. 1 is a schematic diagram of a non-roaming architecture of a 5G system;

FIG. 2 is a diagram of a roaming architecture of the 5G system;

FIG. 3 is a schematic view of a MEC platform;

fig. 4 is a schematic architecture diagram of a communication system according to an embodiment of the present application;

FIG. 5 is a schematic flow chart of a communication method according to the embodiment of the present application;

fig. 6 is a second flow chart of a communication method according to the embodiment of the present application;

fig. 7 is a flow chart diagram III of a communication method according to the implementation of the present application;

fig. 8 is a flow chart diagram of a communication method according to an embodiment of the present application;

fig. 9 is a flow chart diagram fifth of a communication method provided in the implementation of the present application;

Fig. 10 is a schematic structural diagram of a communication device according to an embodiment of the present application;

fig. 11 is a schematic structural diagram of a communication device according to an embodiment of the present application.

Detailed Description

It is convenient to understand that technical terms related to the embodiments of the present application are first described below.

1. Fifth generation (5th generation,5G) mobile communication systems (5G systems, 5gs for short):

fig. 1 is a schematic diagram of a 5GS non-roaming architecture. As shown in fig. 1, 5GS includes: access Networks (ANs) and Core Networks (CNs), may further include: and (5) a terminal.

The terminal may be a terminal having a transceiver function, or a chip system that may be provided in the terminal. The terminal may also be referred to as a User Equipment (UE), an access terminal, a subscriber unit (subscriber unit), a subscriber station, a Mobile Station (MS), a remote station, a remote terminal, a mobile device, a user terminal, a wireless communication device, a user agent, or a user device. The terminals in embodiments of the present application may be mobile phones (mobile phones), cellular phones (cellular phones), smart phones (smart phones), tablet computers (pads), wireless data cards, personal digital assistants (personal digital assistant, PDAs), wireless modems (modems), handheld devices (handsets), laptop computers (lap computers), machine type communication (machine type communication, MTC) terminals, computers with wireless transceiving functions, virtual Reality (VR) terminals, augmented reality (augmented reality, AR) terminals, wireless terminals in industrial control (industrial control), wireless terminals in unmanned aerial vehicle (self driving), wireless terminals in smart grid (smart grid), wireless terminals in transportation security (transportation safety), wireless terminals in smart city (smart city), wireless terminals in smart home (smart home), roadside units with functions, RSU, etc. The terminal of the present application may also be an in-vehicle module, an in-vehicle component, an in-vehicle chip, or an in-vehicle unit built into a vehicle as one or more components or units.

The AN is used for realizing the function related to access, providing the network access function for authorized users in a specific area, and determining transmission links with different qualities according to the level of the users, the service requirements and the like so as to transmit user data. The AN forwards control signals and user data between the terminal and the CN. The AN may include: an access network device, which may also be referred to as a radio access network device (radio access network, RAN) device. The CN is mainly responsible for maintaining subscription data of the mobile network and providing session management, mobility management, policy management, security authentication and other functions for the terminal. The CN mainly comprises the following steps: a user plane function (user plane function, UPF), an authentication server function (authentication server function, AUSF), an access and mobility management function (access and mobility management function, AMF), a session management function (session management function, SMF), a network slice selection function (network slice selection function, NSSF), a network opening function (network exposure function, NEF), a network storage function (network repository function, NRF), a policy control function (policy control function, PCF), a unified data management (unified data management, UDM), a unified data store (unified data repository, UDR), and an application function (application function, AF).

As shown in fig. 1, a UE accesses a 5G network through RAN equipment, and the UE communicates with an AMF through an N1 interface (abbreviated as N1); the RAN communicates with the AMF through an N2 interface (N2 for short); the RAN communicates with UPF through N3 interface for short, N3; the SMF communicates with the UPF through an N4 interface (abbreviated as N4), and the UPF accesses a Data Network (DN) through an N6 interface (abbreviated as N6). In addition, the control plane functions such as AUSF, AMF, SMF, NSSF, NEF, NRF, PCF, UDM, UDR and AF shown in fig. 1 are interacted with by using a service interface. For example, the server interface provided by the AUSF is Nausf; the AMF provides a service interface as Namf; the SMF provides a service interface as Nsmf; the NSSF provides a service interface for the outside as Nnssf; the NEF provides a service interface for the outside as Nnef; the service interface externally provided by the NRF is Nnrf; the PCF provides a service interface for the outside as an Npcf; the service interface externally provided by the UDM is Nudm; the service interface externally provided by the UDR is Nudr; the service interface provided by the AF is Naf.

The RAN device may be a device that provides access to the terminal. For example, the RAN device may include: the next generation mobile communication system, such as a 6G access network device, such as a 6G base station, or in the next generation mobile communication system, the network device may have other nomenclature, which is covered by the protection scope of the embodiments of the present application, which is not limited in any way. Alternatively, the RAN device may also include a 5G, such as a gNB in a New Radio (NR) system, or one or a group (including multiple antenna panels) of base stations in the 5G, or may also be a network node, such as a baseband unit (building base band unit, BBU), or a Centralized Unit (CU) or a Distributed Unit (DU), an RSU with a base station function, or a wired access gateway, or a core network of the 5G, which constitute the gNB, the transmission point (transmission and reception point, TRP or transmission point, TP), or the transmission measurement function (transmission measurement function, TMF). Alternatively, the RAN device may also include an Access Point (AP) in a wireless fidelity (wireless fidelity, wiFi) system, a wireless relay node, a wireless backhaul node, various forms of macro base stations, micro base stations (also referred to as small stations), relay stations, access points, wearable devices, vehicle devices, and so on.

UPF is mainly responsible for user data processing (forwarding, receiving, charging, etc.). For example, the UPF may receive user data from a Data Network (DN), which is forwarded to the terminal through the access network device. The UPF may also receive user data from the terminal through the access network device and forward the user data to the DN. DN refers to an operator network that provides data transfer services for subscribers. Such as the internet protocol (internet protocol, IP) Multimedia Services (IMS), the internet, etc. The DN may be an external network of the operator or a network controlled by the operator, and is configured to provide service to the terminal device. In a protocol data unit (protocol data unit, PDU) session, the UPF, also referred to as protocol data unit session anchor (protocol data unit Session Anchor, PSA), is directly connected to the DN through N6.

The AUSF is mainly used to perform security authentication of the terminal.

AMF is mainly used for mobility management in mobile networks. Such as user location updates, user registration networks, user handoffs, etc.

SMF is mainly used for session management in mobile networks. Such as session establishment, modification, release. Specific functions are, for example, assigning internet protocol (internet protocol, IP) addresses to users, selecting a UPF that provides packet forwarding functionality, etc.

The PCF is mainly responsible for providing a unified policy framework to control network behavior, providing policy rules to control layer network functions, and acquiring user subscription information related to policy decisions. The PCF may provide policies to the AMF, SMF, such as quality of service (quality of service, qoS) policies, slice selection policies, etc.

NSSF is mainly used to select network slices for terminals.

NEF is mainly used to support the opening of capabilities and events.

UDM is mainly used for storing user data such as subscription data, authentication/authorization data, etc.

The UDR is mainly used for storing structured data, and the stored content includes subscription data and policy data, externally exposed structured data and application-related data.

AF mainly supports interactions with CN to provide services, such as influencing data routing decisions, policy control functions or providing some services of third parties to the network side.

Fig. 2 is a diagram of a roaming architecture of 5GS, where the 5G network includes an HPLMN and a VPLMN, the HPLMN being a home network of the UE, the VPLMN being a roaming network of the UE, the VPLMN and the HPLMN communicating through vSEPP and hSEPP. In the scenario shown in fig. 2, traffic may be deployed at the HPLMN, i.e. the DN is at the HPLMN (not shown in the figure), and the terminal communicates with the DN by establishing a session of home routing. Alternatively, the service may be located in the V-PLMN, i.e. the DN is in the V-PLMN, and the terminal establishes a local session with the DN of the V-PLMN. Optionally, for a home routed session scenario, an intermediate UPF may be inserted in the session so that the terminal may access traffic in the data network located in the V-PLMN. Specific architecture can be referred to TS (technical specification, technical standard) 23.548.

As shown in fig. 2, in the VPLMN, a UE accesses a 5G network through RAN equipment, and the UE communicates with an AMF through an N1 interface (abbreviated as N1); the RAN equipment communicates with the AMF through an N2 interface (N2 for short); the RAN equipment communicates with the UPF through an N3 interface (N3 for short); the SMF communicates with the UPF through an N4 interface (N4 for short). In the HPLMN, UPF accesses DN through N6 interface (N6 for short); the UPF communicates with the SMF via an N4 interface (N4 for short). And the UPF within the VPLMN communicates with the UPF within the HPLMN through an N9 interface (abbreviated as N9). In addition, the control plane functions such as NSSF, NEF, AMF, SMF, NRF of the VPLMN or PCF shown in fig. 2 use a service interface for interaction. For example, the external service interface provided by the AMF is Namf; the SMF provides a service interface as Nsmf; the NSSF provides a service interface for the outside as Nnssf; the NEF provides a service interface for the outside as Nnef; the service interface externally provided by the NRF is Nnrf; the service interface provided by PCF is the Npcf. The control plane functions of the HPLMN UDM, AUSF, PCF, NRF, NSSF, AF, or NEF, etc. shown in fig. 2 also use the servitization interface for interaction. For example, the server interface provided by the AUSF is Nausf; the service interface externally provided by the UDM is Nudm; the service interface provided by the AF is Naf. The "Nxx" between two shown in fig. 2 represents an interface between the two, and is not specifically exemplified.

2. Network slice

Network slicing is a key technology generated by 5G networks under the common drive of requirements and technologies.

From the demand point of view, the target market of the 5G network includes differentiated services such as enhanced mobile broadband (enhanced mobile broadband, eMBB), mass internet of things (massive internet of things, mhiot), ultra-high reliability ultra-low latency communication (URLLC), and the like, and it is difficult to adapt to various different use cases simultaneously by adopting a traditional single network, so that the cost is greatly increased when a plurality of independent physical networks are deployed. Therefore, the 5G network needs to support the realization of multi-dimensional logic isolation of services, functions, security, transmission, operation and maintenance and the like on the basis of hardware resource sharing. From the technical evolution perspective, with the increasing popularity of network function virtualization (network functions virtualization, NFV) and Software Defined Networking (SDN), a powerful technical support is provided for network function modularization, component arrangement and management, dynamic configuration and efficient scheduling of network resources. For the above reasons, on a unified network infrastructure, in order to provide mutually isolated network environments for different application scenes, flexibly customize network functions and characteristics according to respective requirements, and ensure the requirements of quality of service (quality of service, qoS) of different services, network slicing is generated.

One network slice may be identified by a single network slice selection assistance information (single network slice selection assistance information, S-nsai) and a plurality of network slices may be identified by a set of slice selection assistance information (network slice selection assistance information, nsai), i.e., a set of S-nsais.

The UE needs to complete registration of one or more network slices during initial registration or mobility registration. For example, in the registration procedure, the AMF network element may carry authentication information corresponding to the one or more network slices, such as Allowed NSSAI, in a registration accept message sent to the UE, so as to indicate that the UE registers with the one or more network slices, that is, the UE may use the one or more network slices. The AMF network element may determine the Allowed nsai according to the UE subscription information and the like acquired from the UDM network element/UDR network element, or acquire the Allowed nsai from the NSSF network element, which is not limited.

Each protocol data unit (protocol data unit, PDU) session of the UE may be associated with one S-nsai, which is one of the Allowed nsais of the UE. For example, when a UE needs to access a service, the UE may obtain an S-nsai corresponding to the service based on a UE routing policy (UE route selection policy, urs) and determine whether to use an existing PDU session or to establish a new PDU session. If an existing PDU session is used, it indicates that the S-NSSAI has been associated with the PDU session. If a new PDU session is to be established, the UE needs to verify whether the S-NSSAI is in the Allowed NSSAI. At this time, if the authentication is successful, the UE may include the S-nsai in the session establishment request to ensure that a subsequently established PDU session, i.e., a new PDU session, is associated with the S-nsai.

3. Edge computation (edge computation, EC)

In 4G and previous conventional mobile network architectures, the user plane devices basically follow a tree topology deployment. That is, the uplink user message passes through the base station and the backhaul network, and finally accesses the data network through the anchor gateways deployed in a centralized manner, where the anchor gateways are typically deployed at a higher position in the network, such as a central machine room of a large area. The topology structure is relatively simple, and the operators can conduct centralized service control and message processing at the anchor points. With the explosive growth of mobile traffic, this deployment approach becomes increasingly difficult to support such rapidly growing mobile traffic models. On one hand, in the network with centralized deployment of anchor gateways, the increased flow is finally concentrated at the gateways and the core machine room, and higher requirements are put on the backhaul network bandwidth, the machine room throughput and the gateway specification; on the other hand, the long-distance return network from the access point to the anchor gateway and the complex transmission environment also lead to larger time delay and jitter of user message transmission.

Based on the background, 5G proposes the concept of EC, and EC realizes local processing of distributed service traffic by moving UPF network elements and service processing capability down to the network edge, so as to avoid excessive concentration of traffic, thereby greatly reducing specification requirements on a core machine room and a centralized gateway. Meanwhile, the distance of the backhaul network is shortened, and the end-to-end (E2E) time delay and jitter of the user message are reduced, so that the deployment of the ultralow-time-delay service is possible. The specific implementation of ECs is typically a relatively dense deployment multiple access edge computing (MEC) platform. However, in practical deployment, it is difficult to implement deployment by a single operator or a third party due to cost and other restrictions. One reasonable way is for multiple operators (or third parties) to co-deploy the MEC platform, the edge support environment (edge hosting environment, EHE). That is, a particular functional MEC platform, or a particular service, may be deployed by different operators at different locations, or the service may be deployed on only a portion of the operators deployed MEC platforms, or the MEC platform may be deployed by only a portion of the operators.

However, in this deployment mode, such a problem arises:

as shown in fig. 3, the UE belongs to the operator a, and the location of the UE currently is covered with the public land mobile network (public land mobile network, PLMN) a of the operator a and the PLMN B of the operator B, where the service X is locally deployed on the MEC platform deployed by the operator B, and where the service X is not deployed on the MEC platform of the operator a, or where the MEC platform deployed by the operator B is not deployed at all. In this scenario, it is possible to deploy the MEC platform of service X, or the server of service X only allows PSA access for operator B. This means that when the UE needs to access service X here, it needs to access service X through the PSA of PLMN B. However, since the current location of the UE is covered with PLMN a, the UE accesses PLMN a, and thus cannot access service X through PSA of PLMNB, which may result in limited access of service X by the terminal.

In summary, in view of the above technical problems, the embodiments of the present application provide a technical solution to solve the problem that terminal access may be limited because an MEC platform deploying a certain service does not support PSA access of other operators.

The technical solutions in the present application will be described below with reference to the accompanying drawings.

The technical solution of the embodiments of the present application may be applied to various communication systems, such as a wireless fidelity (wireless fidelity, wiFi) system, a vehicle-to-vehicle (vehicle to everything, V2X) communication system, an inter-device (D2D) communication system, a 4G, such as a long term evolution (long term evolution, LTE) system, a worldwide interoperability for microwave access (worldwide interoperability for microwave access, wiMAX) communication system, a 5G, such as a new radio, NR) system, and a future communication system.

The present application will present various aspects, embodiments, or features about a system that may include multiple devices, components, modules, etc. It is to be understood and appreciated that the various systems may include additional devices, components, modules, etc. and/or may not include all of the devices, components, modules etc. discussed in connection with the figures. Furthermore, combinations of these schemes may also be used.

In addition, in the embodiments of the present application, words such as "exemplary," "for example," and the like are used to indicate an example, instance, or illustration. Any embodiment or design described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments or designs. Rather, the term use of an example is intended to present concepts in a concrete fashion.

In the embodiment of the present application, "information", "signal", "message", "channel", and "signaling" may be used in a mixed manner, and it should be noted that the meaning of the expression is matched when the distinction is not emphasized. "of", "corresponding" and "corresponding" are sometimes used in combination, and it should be noted that the meanings to be expressed are matched when the distinction is not emphasized. Furthermore, references to "/" herein may be used to indicate a relationship of "or".

The network architecture and the service scenario described in the embodiments of the present application are for more clearly describing the technical solution of the embodiments of the present application, and do not constitute a limitation on the technical solution provided in the embodiments of the present application, and those skilled in the art can know that, with the evolution of the network architecture and the appearance of the new service scenario, the technical solution provided in the embodiments of the present application is also applicable to similar technical problems.

To facilitate understanding of the embodiments of the present application, a communication system suitable for the embodiments of the present application will be described in detail first with reference to the communication system shown in fig. 4 as an example. Fig. 4 is a schematic architecture diagram of a communication system to which the communication method according to the embodiment of the present application is applicable.

As shown in fig. 4, the communication system may be applied to the above 5G system, and mainly includes: UE, network elements within network 1, such as UPF, AMF, SMF, PCF, NSSF, AF, and network elements within network 2, such as SMF2, PSA, EASDF.

Where the UE accesses the network 1, the network 1 is the home network of the UE, i.e. the home public land mobile network (home public land mobile network, HPLMN), which generally refers to a PLMN deployed by the home operator of the UE or the operator to which the UE is subscribed. For example, the UE is a china mobile card, the home operator of the UE is china mobile, and the HPLMN of the UE is a PLMN deployed by china mobile. Network 2 is a different PLMN than network 1, such as a PLMN deployed by a different operator, or network 2 is a network other than network 1. Network 1 and network 2 may be related, for example, network 2 is a subscription network for network 1, in which case network 1 may typically obtain related information, such as SMF2 information, from network 2. Of course, in the case where the network 1 is able to acquire the relevant information from the network 2, the network 1 and the network 2 may not be related, for example, the network 2 is not a subscription network of the network 1, and is not limited thereto. For the UE, the network 2 may also be referred to as the non-HPLMN of the UE. The network 2 is deployed with a service 1 of the MEC platform, which service 1 may be limited to PSA access through the network 2 or service 1 may be limited to PSA access through the PLMN deploying the service 1, i.e. service 1 may not be able to PSA access through the network 1. This property of service 1 may also be referred to as the X property (or a particular property, or any other possible expression). Thus, a service similar in nature to service 1, i.e. a service limited to PSA access by the PLMN deploying the service, may be referred to as a service of nature X. The network 2 may be understood as a PLMN other than the home PLMN, which may be referred to as a non-home PLMN, or a PLMN other than the home PLMN which deploys EC/MEC services and which does not support UPF access by the home PLMN, or a PLMN other than the home PLMN which is capable of accessing EC/MEC services and which does not support UPF access by the home PLMN.

In the embodiment of the application, the AMF may obtain the single network slice selection auxiliary information (single network slice selection assistance information, S-NSSAI) associated with the service 1 in advance. When the UE requests access to service 1, the AMF may find SMF1 and SMF2 from the S-nsai associated with service 1. As such, SMF1 may select UPF for the UE and SMF2 may select PSA for the UE. The SMF1 and the SMF2 can establish user plane connection, so that the UE can access the PSA through UPF to realize access to the service 1, thereby solving the problem that the UE access is limited because the MEC platform for deploying the service 1 does not support the PSA access of other operators.

It is noted that existing standards are not well defined for visiting public land mobile networks (visited public land mobile network, VPLMN). In the architecture related to the existing standard, two 5G networks deployed by different operators are both roaming scenarios, i.e. scenarios where the UE accesses a non-HPLMN. Thus in the existing standard, a scenario involving a non-HPLMN, which is necessarily the VPLMN to which the UE has access. In the embodiment of the application, however, the UE accesses the HPLMN, i.e. the network 1; thus a non-HPLMN, i.e. network 2, may not be understood as a VPLMN in the general sense. Of course, for convenience of description, in the embodiment of the present application, the network 2 may also be referred to as a VPLMN, or a visited PLMN, without limitation.

In this embodiment of the present application, the network 1 mentioned below may be understood as a first network, the network 2 may be understood as a second network, the service 1 may be understood as a first service, the UE may be understood as a terminal, the access and mobility management network element may be understood as an AMF, the first session management network element may be understood as an SMF1, the second session management network element may be understood as an SMF2, the policy control network element may be understood as a PCF, and the network slice selection network element may be understood as an NSSF, etc., and in addition, other terms, such as a first slice identifier and S-nssai#1, a second slice identifier and S-nssai#2, etc., may be understood similarly, and will not be described in detail.

For convenience of understanding, the following describes in detail, by way of method embodiments, the interaction procedure between each network element/device in the above-mentioned communication system with reference to fig. 5 to fig. 9. The communication method provided by the embodiment of the application can be applied to the communication system and is specifically applied to various scenes mentioned in the communication system, and is specifically described below.

Scene 1:

fig. 5 is a schematic flow chart of a communication method according to an embodiment of the present application. In scenario 1, the S-NSSAI associated with service 1 may be S-NSSAI #1 for service 1 in network 1. The AMF may determine SMF1 based on S-NSSAI#1, and S-NSSAI#2 for service 1 in network 2, and SMF2 based on S-NSSAI#2. As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Specifically, as shown in fig. 5, the flow of the communication method is as follows:

s500, the AMF acquires the association relationship.

The association relationship may be an association relationship between the identities of the S-nsai #1, the S-nsai #2, and the network 2.

Wherein, S-NSSAI#1 may be S-NSSAI of service 1 in network 1. Service 1 may also have other S-NSSAIs in network 1, without limitation. Since traffic 1 is deployed on network 2, but not on network 1, S-NSSAI#1 can be understood as a mapping of S-NSSAI#2 within network 1. S-NSSAI#1 is different from S-NSSAI of any normal service. Because if there is a certain S-nsai, which is both the S-nsai of a certain normal service and the mapping of the S-nsai of service 1 on the network 1, the AMF cannot distinguish between the two services according to S-nsai#1, and cannot determine whether to select SMF2 according to the two services. That is, when a certain service is actually deployed in the network 1, it is also possible to deploy a slice corresponding to S-nsai of the service in the network 1. However, since network 1 does not deploy service 1, such as the EAS or MEC platform of service 1, network 1 does not actually have the slice corresponding to S-nsai#1. For network 1, S-nsai#1 is an identification defined for facilitating selection of SMF2, and a slice corresponding to S-nsai#1 may also be understood as a virtually existing slice in network 1.

It should be noted that, the common service mentioned in the embodiment of the present application may refer to: not only PSA access through the network deploying the service, but also PSA access through all other networks except the network. For example, where the network includes network 1, network 2, and network 3, service a is deployed in network 1, and service a allows PSA access through network 1, and also allows PSA access through each of network 2 and network 3, service a may be considered a normal service. A certain service is understood to be a normal service, a service of the nature X, and not limited if it allows PSA access not only through the network where it is deployed but also through other parts of the network than the network. For example, the network includes network 1, network 2, and network 3, with service a deployed at network 1, service a allowing PSA access through network 1, PSA access through network 2, but not PSA access through network 3. Then, for network 2, the traffic a is a normal traffic, and for network 3, the traffic a is a traffic of nature X.

S-nsai #2 may be the S-nsai of service 1 in network 2. There is a slice corresponding to S-nsai #2 in network 2, such as slice 1, to provide the service required by service 1. In addition, the service 1 may have other S-NSSAI in the network 2, which is not limited.

The identity of the network 2 may be a PLMN2 ID. Since there may be other networks besides the network 1 and the network 2, such as the network 1 has subscribed to the network 3, at this time, the S-nsai#2 may be the same as a certain S-nsai in the network 3, so to avoid the S-nsai#2 being associated to other networks, the identity of the network 2 may be added in the association relationship to ensure that the S-nsai#2 may be associated to only the network 2.

By way of example, one implementation of the association relationship may be as shown in table 1 below.

TABLE 1

Wherein S-NSSAI#1 is the S-NSSAI of service 1 in network 1. S-nsai #2 is the S-nsai of service 1 in network 2. S-nsai #3 is an S-nsai deployed in network 2, and other traffic with X properties (e.g., traffic 2) is in network 1. S-nsai #4 is the S-nsai of service 2 in network 2. PLMN2 ID is an identification of network 2. S-nsai#a is an S-nsai deployed in other networks (e.g., network 3) and other traffic with X properties (e.g., traffic 3) in network 1. S-NSSAI#b service 3S-NSSAI at network 3. S-nsai#c is an S-nsai deployed in network 3 and other traffic with X properties (e.g. traffic 4) is in network 1. S-nsai#d is the S-nsai of service 4 in network 3. PLMN3ID is an identification of network 3. S-nsai # 1-S-nsai #2 may be used to represent the same slice, e.g., slice 1 exists in network 1 and network 2, respectively, S-nsai for slice 1 to provide the services required by service 1. S-nsai # 3-S-nsai #4 may be used to represent the same slice, e.g., S-nsai for slice 2 in network 1 and network 2, respectively, where slice 2 exists in network 2 and may be used to provide the services required by traffic 2. S-nsai #a-S-nsai #b may be used to represent the same slice, e.g., slice 3 is in the S-nsai of network 1 and network 3, respectively, and the slice 3 exists in the network 3 to provide the services required by the traffic 3. S-nsai #c-S-nsai #d may be used to represent the same slice, e.g., S-nsai of slice 4 in network 1 and network 3, respectively, the slice 4 being present in network 3 for providing the services required by traffic 4. Further, any two or more of the services 1 to 4 may be the same service. That is, the same service may need to be provided with its required services by multiple slices.

Alternatively, another implementation of the association relationship may be as shown in tables 2 and 3 below.

TABLE 2

S-NSSAI#1-S-NSSAI#2
	S-NSSAI#3-S-NSSAI#4
S-NSSAI#a-S-NSSAI#b
	S-NSSAI#c-S-NSSAI#d
…

TABLE 3 Table 3

PLMN1 ID	S-NSSAI#1,S-NSSAI#3,S-NSSAI#a,S-NSSAI#c…
		PLMN2 ID	NSSAI#2,NSSAI#4…
PLMN3 ID	S-NSSAI#b,S-NSSAI#d…
		…	…

Wherein, table 2 may be used to represent the mapping relationship of the slices, for example, the mapping relationship between S-nsais, and the specific meaning may refer to the related description in table 1, and will not be repeated. Table 3 may be used to characterize the deployment relationship of the slice, such as the correspondence of S-nsai to PLMN IDs, i.e. to indicate which network the slice in table 2 specifically belongs to. That is, in this case, the association relationship may be composed of two relationships, that is, a mapping relationship of the slices, and a deployment relationship of the slices, respectively.

It should be noted that table 2 is similar to the "mapping of S-nsai" in the existing standard, but is different in that the "mapping of S-nsai" in the existing standard only includes the mapping relationship between HPLMN and slices of one VPLMN, and the mapping relationship between slices in table 2 may be the mapping relationship between slices of many different networks, and is not limited to the mapping relationship between HPLMN and VPLMN. Table 3 differs from any entry in the existing standard in that in roaming scenarios, since the VPLMN is deterministic or unique because the UE has been accessed/registered to the VPLMN, the existing standard does not need to label the mapping relation of the slice with the set of mapping relations belonging to the HPLMN and which VPLMN, i.e. the deployment information of the slice is not needed. In other words, table 3 may be a newly defined entry.

It should also be noted that the association relationship also needs to satisfy the following constraint conditions: if there are different X-nature services, then these services need to be different at the S-nsai of network 1 and the S-nsai of network 2, and any one service needs to be different at the S-nsai of network 1 than the other services. This is because, if the same S-nsai exists, after the AMF receives the S-nsai from the UE, it cannot be determined which service the S-nsai is, and it cannot be determined which service the S-nsai is associated with, resulting in a flow failure. Thus, in determining the slice map, network 1 typically negotiates with other networks, such as network 2 (this negotiation may be commercial, e.g., SLA, etc., not necessarily implemented by 3GPP or other network steps), to ensure that each S-NSSAI is unique. It will be readily appreciated that this condition is illustrated by the above example: S-NSSAI#1, S-NSSAI#3, S-NSSAI#a, and S-NSSAI#c are different from each other, S-NSSAI#2, S-NSSAI#4, S-NSSAI#b, and S-NSSAI#d are different from each other, and S-NSSAI#1, S-NSSAI#3, S-NSSAI#a, and S-NSSAI#c are different from S-NSSAI#2, S-NSSAI#4, S-NSSAI#b, and S-NSSAI#d. That is, each S-NSSAI in the above example is unique.

It will be appreciated that the foregoing is exemplified by service 1-service 4, and is not limited thereto. There may be more or fewer services actually deployed, and thus corresponding entries or cells in the table are added or subtracted accordingly. For example, if there is no service 4, then there is no S-NSSAI#c-S-NSSAI#d in Table 1, or there is no S-NSSAI#c-S-NSSAI#d in Table 2, and there is no S-NSSAI#d in Table 3, and so on. Or if the service 5 still exists, adding a term corresponding to the service 5 in table 1, or adding a term corresponding to the service 5 in tables 2 and 3 to characterize an association relationship corresponding to the service 5, and the specific implementation can refer to the description and will not be repeated. It will be appreciated that the services involved may be of nature X or normal except that service 1 is required to be used as an example. In addition, the foregoing describes only some implementations of the association relationship, and other implementations are possible, which are not limited.

It should also be understood that the foregoing are merely some exemplary implementations of the association relationship, and are not limiting. For example, if there are no other networks other than the network 1 and the network 2, such as the network 1 does not sign up for other networks other than the network 2, the association relationship may not include the identity of the network 2, that is, the association relationship may be only the association relationship of the S-nsai#1 and the S-nsai#2.

In the embodiment of the present application, the manner in which the AMF obtains the association relationship is not limited. For example, the AMF may configure the association locally, such as by a roaming agreement between operators, or may obtain the association from other network elements (such as NSSF, etc.). In addition, the association relationship may be PLMN granularity information, which may be irrelevant to UE or PDU session, and thus, the AMF obtaining the association relationship may be regarded as enhancement of the AMF's ability to perceive own information.

S501, the AMF acquires an S-NSSAI list 1.

The S-nsai list 1 may include S-nsai (including S-nsai # 1) of the service having the property X (including service 1) in the network 1. The S-NSSAI list 1 may be used by the AMF to determine whether the received S-NSSAI is that of an X-property service or an ordinary service. The AMF may obtain the S-nsai list 1 from the PCF through the registration procedure, e.g., the S-nsai list 1 is carried in an AMF policy control creation (npcf_amfpoliccontrol_create) message of the registration procedure, or any possible message of the registration procedure, without limitation. That is, AMF acquisition of S-NSSAI List 1 may be considered an enhancement to existing registration procedures. Alternatively, the AMF may obtain the S-nsai list 1 from other possible network elements, such as NSSF. At this time, the AMF policy control creation message may be replaced with a network slice (NSS) selection Get (nssf_nsselection_get) message, or an NSSAI available Update (nssf_nssaiaivailability_update) message or other possible message. Alternatively, the AMF may obtain the S-NSSAI list 1 in other ways, such as a local configuration.

It will be appreciated that in the existing standard, if the AMF receives an S-nsai from the UE, the AMF defaults to processing logic for normal traffic, i.e. selects a corresponding one of the SMFs according to the S-nsai. However, if this S-nsai is that of the X-property service, the AMF still executes the processing logic of the normal service, and selects the SMF in the network 1, but cannot select the SMF in the network 2, which eventually results in that the UE cannot access the X-property service. Thus, the AMF may obtain S-NSSAI list 1 to determine whether the received S-NSSAI is the S-NSSAI of the X-property traffic or the S-NSSAI of the normal traffic. If the service is the S-NSSAI of the normal service, the AMF executes the processing logic of the normal service. If the AMF is S-NSSAI of the X-property service, the AMF can be associated and matched with the relationship to determine the SMF in the network 1 and the SMF in the network 2, and the specific reference can be made to the following S505, which is not repeated.

It should be noted that any one of the S-nsais in the S-nsai list 1 is different from any one of the H-S-nsais of the normal service deployed in the network 1. This can be understood as a precondition for the implementation of the solution of the present embodiment, since if there is a certain S-nsai, which is both a S-nsai of a certain normal service deployed in the network 1 and a S-nsai of a certain property X of the service in the network 1, the AMF cannot distinguish the two services according to the S-nsai, and cannot determine whether to select the SMF in the network 2 according to this.

It will also be appreciated that S501 is an optional step, for example, the AMF may not acquire the S-nsai list 1, in which case the AMF may default to match the received S-nsai with an association relationship to determine whether the S-nsai is an S-nsai of an X-property service or an S-nsai of a normal service.

S502, the AMF sends a registration accept (registration accept) message to the UE. Accordingly, the UE receives a registration accept message from the AMF.

The AMF may send a registration accept message to the UE in the registration procedure, to indicate that the UE is allowed to register with the network 1. The registration accept message may include S-nsai #1 and Allowed nsai #1. The S-nsai #1 may be carried in an existing cell to reduce implementation difficulty, such as a UE routing policy (UE route selection policy, urs) to indicate that the S-nsai of the service 1 is S-nsai #1, or may be carried in a newly defined cell to improve implementation flexibility, without limitation. The Allowed NSSAI#1 may include S-NSSAI#1 to indicate that the slice corresponding to S-NSSAI#1 is a slice available to the UE or a slice authorized to allow the UE to access or use. The Allowed NSSAI#1 may also include other S-NSSAIs than S-NSSAI#1, such as S-NSSAIs of traffic deployed in the network 1.

To this end, the AMF perceived information includes: association and S-nsai list 1. The information perceived by the UE includes: S-NSSAI#1 and Allowed NSSAI#1. The parties can establish a session accordingly.

It should be noted that, after receiving S-nsai#1, the UE may not sense which network S-nsai s#1 acquired by itself. That is, in scenario 1, the UE may process, e.g., use or transmit, S-nsai#1 in accordance with existing standard processing methods. In other words, the UE may consider the above S-nsai #1 to be actually a normal S-nsai, such as the S-nsai of the service deployed by the network 1, and the UE may not perceive whether or not access to the service through the V-PSA is required.

It is further understood that S501 and S502 are performed in the registration procedure, but there is no trigger relationship. With the evolution of the standard, the registration process in the embodiment of the present application also evolves into a corresponding process. Alternatively, the registration procedure may be replaced by any possible procedure, and the registration acceptance message may be replaced by any possible message accordingly, without limitation.

S503, the UE determines to trigger the session establishment.

In case of desiring to access service 1, the UE may acquire S-nsai #1, e.g., determine that S-nsai of service 1 is S-nsai #1 according to the urs. The UE may authenticate using S-NSSAI#1 and Allowed NSSAI#1, e.g., by determining that Allowed NSSAI#1 contains S-NSSAI#1. In this manner, the UE determines that authentication is passed, thereby determining to trigger establishment of a PDU session, and performs S504. Of course, if authentication fails, execution may continue in the existing manner.

S504, the UE sends a PDU session establishment request (PDU session establishment request) message to the AMF. Accordingly, the AMF receives the PDU session establishment request message from the UE.

The PDU session establishment request message may be used to request to establish a PDU session, for example, including S-nsai #1, to request to establish a PDU session for the S-nsai #1, that is, a PDU session of service 1.

S505, AMF determines SMF2 according to S-NSSAI#1.

The AMF may determine the identity associated with S-NSSAI#1 to S-NSSAI#2 and network 2 from S-NSSAI#1 from the UE, i.e., S-NSSAI#1 in the PDU session establishment request message. For example, the AMF may traverse S-NSSAI list 1 based on S-NSSAI#1 to determine that S-NSSAI#1 is included in S-NSSAI list 1, thereby determining the identity of the S-NSSAI#1 associated with S-NSSAI#2 and network 2 based on S-NSSAI#1 and the association. Alternatively, after the AMF receives the S-nsai#1 from the UE, the identity of the S-nsai#1 associated with the S-nsai#2 and the network 2 may be determined directly according to the S-nsai#1 and the association relationship. Wherein, if the association is implemented in the manner of table 1, the AMF may use S-nsai#1 to look up table 1 to determine the identity of the S-nsai#1 associated with S-nsai#2 and network 2. If the association is implemented in the manner of tables 2 and 3, the AMF may use S-NSSAI#1 to look up table 2 to determine that S-NSSAI#1 is associated with S-NSSAI#2 and then use S-NSSAI#2 to look up table 3 to determine that S-NSSAI#2 is associated with PLMN2 ID, i.e., to determine that S-NSSAI#1 is associated with PLMN2 ID. It will be appreciated that this way of table lookup can also be generalized to the determination of the identity of the S-nsai #1 associated to the S-nsai #2 and the network 2 by the AMF based on the S-nsai #1, the mapping of the slices, and the deployment of the slices.

The AMF can select SMF1 according to S-NSSAI#1, and its specific implementation is similar to the existing standard, and it can be understood with reference to the description thereof is omitted. However, unlike the AMF selecting SMF in the existing standard, since the PSA corresponding to the DNN in the embodiment of the present application is located in the network 2 and is not managed/controlled by the SMF1 in the network 1, the AMF selecting SMF1 in the network 1 may not consider the DNN. And, the AMF may select SMF2 according to the S-nsai #2 and the identity of the network 2. Wherein the AMF may send the identities of S-nssai#2 and network 2 to the NRF, such as sending an NF discovery Request (nnrf_nfdiscovery_request) message carrying the identities of S-nssai#2 and network 2, and the NF discovery Request message indicates that the discovered network element is an SMF. Accordingly, the NRF may select SMF2 according to the NF discovery request message, so as to return an address or an identifier of SMF2 to the AMF, for example, the AMF returns an NF discovery Response (nnrf_nfdiscovery_response) message carrying the address or the identifier of SMF2. Of course, if the AMF determines that the S-nsai from the UE is not in the S-nsai list 1, or that there is no S-nsai and network identity matching it in the association, the AMF performs the existing procedure.

It will be appreciated that the above-described manners of selecting SMFs by AMFs are only examples and are not limited thereto. For example, if there are no other networks other than network 1 and network 2, the AMF may also select SMF2 based on S-nssai#2 only. Alternatively, AMF may default to S-NSSAI#1 being associated with SMF2, so that AMF determines SMF2 directly from S-NSSAI#1. Alternatively, AMF may default to S-NSSAI#2 being associated with SMF1, so that AMF determines SMF1 directly from S-NSSAI#2.

S506, the AMF sends the SMF2 identification to the SMF 1. Accordingly, SMF1 receives an identification of SMF2 from the AMF.

The identifier of SMF2 may be carried in a PDU session creation context (nsmf_pduse_createsmcontext) message, or may be carried in any other possible message, without limitation. If the AMF obtains the address of SMF2 in S505, the AMF may convert the address of SMF2 into the identifier of SMF2, and then encapsulate the identifier of SMF2 into the PDU session creation context message; alternatively, the AMF may directly send the address of the SMF2 to the SMF1, which is not limited.

S507, SMF1 selects UPF and configures N4 session corresponding to UPF.

Wherein SMF1 may select a UPF within network 1 according to the PDU session creation context and configure an N4 session for the UPF.

S508, SMF1 sends a PDU session creation Request (nsmf_pduse_create Request) message to SMF 2. Accordingly, SMF2 receives the PDU session creation request message from SMF 1.

Due to the identification or address of SMF2 that SMF1 has obtained, SMF1 may send a PDU session creation request message to SMF2 accordingly to request that SMF2 select the appropriate PSA for the PDU session of service 1. For example, the PDU session creation request message may include at least one of the following: indication information, an identification of the first service, or UE location information.

Wherein the indication information may be used to instruct the SMF2 to select PSA, and not select UPF that is not an anchor point, i.e. a split point in the network 2. The identity of the first service is used to select a PSA that supports access to the first service. The UE location information may include at least one of: tracking Area (TA) information (e.g., tracking area code (tracking area code, TAC) or tracking area identity (tracking area identity, TAI)), cell identity (cell ID), data network access identity (data network access identifier, DNAI), or actual location information (e.g., latitude and longitude information or geographic location information (e.g., XX city, XX county, XX region, etc.), etc.

If the UE location information is internal to network 1, for the cross-network case, SMF2 in network 2 may not be able to identify this information and use it to select PSA as well. Thus, it is possible that the SMF1 configures a correspondence relationship between the location information that can be identified by the network 1 and the UE location information that can be identified by the network 2. For example, SMF1 configures the correspondence of TAIs of network 1 and DNAIs of network 2. In this case, the SMF1 may determine location information that can be identified by the network 1, such as TAI of the network 1, according to the current location of the UE, so as to determine UE location information that can be identified by the network 2 corresponding to the current location of the UE, such as DNAI of the network 2, according to the UE location information of the network 1 and the correspondence, and then send the UE location information that can be identified by the network 2 to the SMF2, so that the SMF2 may select PSA according to this. It will be appreciated that the correspondence may be locally preconfigured by SMF1, or may be obtained by SMF1 from AF, or may be perceived by SMF1 via other means, without limitation.

Alternatively, it is another possibility that the SMF2 configures a correspondence relationship between UE location information that can be identified by the network 1 and location information that can be identified by the network 2. In this case, the SMF1 may transmit UE location information identifiable by the network 1 to the SMF2 according to the current location of the UE. After the SMF2 receives the UE location information that can be identified by the network 1, the location information that can be identified by the network 2 corresponding to the current location of the UE can be determined according to the UE location information that can be identified by the network 1 and the correspondence, so as to select PSA according to the location information. It may be appreciated that the correspondence may be locally preconfigured by SMF2, or may be obtained by SMF2 from other network elements, or may be perceived by SMF1 through other manners, which is not limited.

Alternatively, it is still another possibility that SMF1 may send the actual location information of the UE to SMF 2. For example, the SMF1 may determine location information, such as TA information, TAI, etc., that can be identified by the network 1 according to the current location of the UE, convert the location information that can be identified by the network 1 into latitude and longitude information, and then send the latitude and longitude information to the SMF 2. After receiving the latitude and longitude information, the SMF2 may convert the latitude and longitude information into location information that can be identified by the network 2, such as a cell identifier, DNAI, and the like, so as to select PSA according to the location information. The SMF1 may locally perform conversion between the location information and the latitude and longitude information, or may also be implemented by other network elements, such as a location management function (location management function, LMF), and the like, without limitation. Similarly, the SMF2 may also perform conversion between UE location information and latitude and longitude information locally, or may also be implemented by other network elements, which is not limited.

S509, SMF2 selects PSA, configures N4 session corresponding to PSA, selects EASDF, and configures DNS processing rule corresponding to EASDF.

Wherein, the SMF2 may determine that PSA in the network 2 needs to be selected instead of the split point in the network 2 according to the indication information. Thus, SMF2 may select an appropriate PSA based on the identity of the first service, and the UE location information, e.g., a PSA that is closer to the UE, less loaded, and supports the first service.

S510, SMF2 sends a PDU session creation Response (nsmf_pduse_create Response) message to SMF 1. Accordingly, SMF1 receives the PDU session creation response message from SMF 2.

The PDU session creation response message may be used to indicate that SMF2 has selected PSA and EASDF, such as including the address of PSA and the address of EASDF.

S511, SMF1 and SMF2 establish a user plane connection.

SMF1 may provide the UPF with the address of the PSA, the address of the RAN to which the UE has access, the address of the EASDF (optional), and the address of the UE (optional), and the UPF address. SMF1 may also provide the UPF address to SMF2 so that SMF2 provides the UPF address to the PSA. So far, the PSA and the UPF both obtain the address of each other, and the user plane connection between the network 1 and the network 2 is successfully established, that is, the PDU session of the service 1 is successfully established.

S512, SMF1 sends a PDU session establishment accept (PDU session establishment accept) message to the UE. Accordingly, the UE receives a PDU session establishment accept message from SMF1.

The PDU session establishment acceptance message may carry the address of the EASDF. Thus, when access to service 1 is required, the UE may send a request message carrying the address of the EASDF over the user plane connection. After the UPF1 obtains the address of the EASDF, it may determine that the UE needs to access the PSA, so as to send the request message to the PSA, so that the PSA responds to the request message to provide the UE with the service corresponding to the service 1.

To sum up, since the AMF can determine SMF1 according to S-nsai#1 of service 1 in network 1 and S-nsai#2 of service 1 in network 2, and determine SMF2 according to S-nsai#2. As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Scene 2:

fig. 6 is a schematic flow chart of a communication method according to an embodiment of the present application. Unlike scenario 1 described above, in scenario 2, the S-NSSAI associated with service 1 may be S-NSSAI #2 where service 1 is in network 2. Based on this, the AMF can determine SMF2 from S-NSSAI#2, and S-NSSAI#1 for service 1 in network 2, and SMF1 from S-NSSAI#1. In this way, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Specifically, as shown in fig. 6, the flow of the communication method is as follows:

s600, the AMF acquires the association relationship.

The specific implementation of S600 is similar to S500, and will be understood with reference to the description thereof.

S601, the AMF obtains S-NSSAI list #2 from the PCF.

The S-nsai list #2 may include S-nsai (including S-nsai # 2) of the service having the property X (including service 1) in the network 2. Similar to the S-NSSAI list 1 described above, S-NSSAI list #2 may also be used by the AMF to determine whether the received S-NSSAI is an S-NSSAI for a service of the X nature or an S-NSSAI for a normal service. The normal service may be a service that is deployed in the network 1 and may be accessed through PSA of the network 1. In addition, the specific manner of acquiring the S-nsai list #2 by the AMF may refer to the related description in S501, and will not be described again.

It will be appreciated that S601 is an optional step, for example, the AMF may not acquire the S-nsai list #2, in which case, the AMF may default to match the received S-nsai with the association relationship, to determine whether the S-nsai is an S-nsai of the X-property service or an S-nsai of the normal service.

S602, the AMF sends a registration accept message to the UE. Accordingly, the UE receives a registration accept message from the AMF.

The AMF may send a registration accept message to the UE in the registration procedure, to indicate that the UE is allowed to register with the network 1. The registration accept message may include S-nsai #2 and Allowed nsai #2. The S-nsai#2 may be carried in an existing cell to reduce implementation difficulty, for example, in a urs p, to indicate that the S-nsai of the service 1 is S-nsai#2, or may be carried in a newly defined cell to improve implementation flexibility, which is not limited. The Allowed NSSAI#2 may include S-NSSAI#2 to indicate that the slice corresponding to S-NSSAI#2 is a slice available to the UE, or an authorized slice. The Allowed NSSAI#2 may also include other S-NSSAIs than S-NSSAI#2, such as S-NSSAIs of traffic deployed in the network 1. That is, S502 differs from S602 in that S502 provides an Allowed NSSAI comprising S-NSSAI #1 and S602 provides an Allowed NSSAI comprising S-NSSAI #2.

To this end, the AMF perceived information includes: association relationship and S-nsai list #2. The information perceived by the UE includes: S-NSSAI#2, and Allowed NSSAI#2 containing S-NSSAI#2. The parties can establish a session accordingly.

It should be noted that, after receiving S-nsai#2, the UE may not sense which one of the S-nsai networks S-nsai#2 acquired by itself. That is, similar to scenario 1, the UE may also process S-NSSAI#2 in the existing standard processing manner. In other words, the UE may also consider the above S-nsai #2 to be actually the S-nsai of the normal service, and the UE may not perceive whether the service needs to be accessed through the V-PSA.

It is also understood that S601-S602 are performed in the registration flow, but there is no trigger relationship. With the evolution of the standard, the registration process in the embodiment of the present application also evolves into a corresponding process. Alternatively, the registration procedure may be replaced by any possible procedure, which is not limited.

S603, the UE determines to trigger the establishment of the session.

In case of desiring to access service 1, the UE may acquire S-nsai #2, e.g., determine that S-nsai of service 1 is S-nsai #2 according to the urs. The UE may authenticate using S-NSSAI#2 and Allowed NSSAI#2, e.g., determine that Allowed NSSAI#2 contains S-NSSAI#2. In this manner, the UE determines that authentication is passed, thereby determining to trigger establishment of a PDU session, and performs S604. Of course, if authentication fails, execution continues in the existing manner.

S604, the UE sends a PDU session establishment request message to the AMF. Accordingly, the AMF receives the PDU session establishment request message from the UE.

The difference between S604 and S504 is that the PDU session establishment request message of S604 carries S-nsai#2, and the rest of the description related to S504 will be omitted.

S605, AMF determines SMF1 according to S-NSSAI#2.

The AMF may determine the identity associated with S-NSSAI#2 to S-NSSAI#1 and network 2 from S-NSSAI#2 from the UE. For example, AMF may traverse S-NSSAI list #2 based on S-NSSAI #2 to determine that S-NSSAI list #2 contains S-NSSAI #2. Thus, the AMF can determine the identity of the S-NSSAI#2 associated with the S-NSSAI#1 and the network 2 based on the S-NSSAI#2 and the association relationship. Alternatively, after the AMF receives the S-nsai#2 from the UE, the identity of the S-nsai#2 associated with the S-nsai#1 and the network 2 may be determined directly according to the S-nsai#2 and the association relationship. It can be understood that, unlike S505, S605 is that the AMF queries the association relationship using S-nsai#2, but the specific query logic is similar to S505, and will not be described in detail.

The AMF may select SMF1 according to S-NSSAI#1, and the AMF may also select SMF2 according to the identifiers of S-NSSAI#2 and network 2, and the specific implementation may refer to the related description in S505 and will not be repeated.

S606, the AMF sends the SMF2 identification to the SMF1. Accordingly, SMF1 receives an identification of SMF2 from the AMF.

S607, SMF1 selects UPF and configures N4 session corresponding to UPF.

S608, the SMF1 sends a PDU session creation request message to the SMF2. Accordingly, SMF2 receives the PDU session creation request message from SMF1.

S609, SMF2 selects PSA, configures N4 session corresponding to PSA, and selects EASDF, configures DNS processing rule corresponding to EASDF.

S610, SMF2 sends a PDU session creation response message to SMF1. Accordingly, SMF1 receives the PDU session creation response message from SMF2.

S611, SMF1 and SMF2 establish a user plane connection.

S612, the SMF1 sends a PDU session establishment accept message to the UE. Accordingly, the UE receives a PDU session establishment accept message from SMF1.

The specific implementation of S606-S612 may refer to the related descriptions of S506-S512, and will not be described again.

To sum up, since the AMF can determine SMF2 according to S-nsai#2 of service 1 in network 1 and S-nsai#1 of service 1 in network 1, and determine SMF1 according to S-nsai#1. As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Scene 3:

fig. 7 is a schematic flow chart of a communication method according to an embodiment of the present application. Unlike scenario 1 and scenario 2 described above, in scenario 3, the S-NSSAI associated with service 1 may include S-NSSAI #1 for service 1 in network 1 and S-NSSAI #2 for service 1 in network 2. The AMF may provide the UE with the S-NSSAI#2 in advance, and the association of the S-NSSAI#1 with the S-NSSAI#2. On this basis, if the UE wants to access service 1, the UE may send S-nsai#1 and S-nsai#2 to the AMF so that the AMF determines SMF1 from S-nsai#1 and SMF2 from S-nsai#2 and the identity of network 2 (optional). As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Specifically, as shown in fig. 7, the flow of the communication method is as follows:

s700, the AMF acquires the association relationship.

The specific implementation of the association relationship may refer to the related description in S500, which is not described herein.

In one possible way, the constraint condition of the association relationship may be similar to S500. For example, each S-NSSAI in the association may be unique.

Alternatively, in another possible manner, the constraint condition of the association relationship may be different from S500. For example, in the association relationship, each service is different in S-nsai of the network 1 and one network other than the network 1. For example, taking Table 1 above as an example, S-NSSAI#1, S-NSSAI#2, S-NSSAI#3, and S-NSSAI#4 are different from each other, and S-NSSAI#a, S-NSSAI#b, S-NSSAI#c, and S-NSSAI#d are different from each other. Also, in the case where there may be a plurality of networks other than the network 1, for the above-described association, S-nsais of respective services in the network 1 and one network other than the network 1 may be the same as S-nsais of respective services in the network 1 and another network other than the network 1, that is, each S-nsai in the association may not be unique. In this case, it may be necessary to distinguish these same S-nsais by the identity of the network. For example, taking Table 1 above as an example, S-NSSAI #1, S-NSSAI #2, S-NSSAI #3, and S-NSSAI #4 may be the same as S-NSSAI in S-NSSAI # a, S-NSSAI # b, S-NSSAI #c, and S-NSSAI #d. Therefore, it is necessary to distinguish these same S-nsais by PLMN2 ID and PLMN3 ID.

S701, the AMF sends a registration accept message to the UE. Accordingly, the UE receives a registration accept message from the AMF.

The AMF may send a registration accept message to the UE in the registration procedure, to indicate that the UE is allowed to register with the network 1. The registration accept message may include S-nsai #1, association, and Allowed nsai #1. The description of the S-nsai#1 and the Allowed nsai#1 in S501 may be referred to above, and will not be repeated. The association relationship may also be carried in the same cell as the above-mentioned S-nssai#1, for example, in USRP; or, the association relationship can be independently carried in other existing cells to reduce the implementation difficulty, or newly defined cells to improve the implementation flexibility, without limitation.

Optionally, the registration accept message may further include an identifier of the network 2, for example, the identifier of the network 2 may be carried in the USRP together with the S-nsai#1 to indicate that the service 1 is deployed in the network 2, or the identifier of the network 2 may also be independently carried in an existing cell, so as to reduce implementation difficulty, or a newly defined cell, so as to improve implementation flexibility, without limitation.

To this end, the AMF perceived information includes: and (5) association relation. The information perceived by the UE includes: s-nsai #1, identity (optional) of network 2, association, and Allowed nsai #1 including S-nsai #1. The parties can establish a session accordingly.

It may be understood that, in the case that each S-nsai in the association relationship is unique, the AMF may provide the UE with the identifier of the network 2, or may not provide the identifier of the network 2, which is not limited. However, in the case that each S-nsai in the association may not be unique, the AMF needs to provide the UE with an identification of the network 2 for the UE to determine the unique S-nsai. Further, performing S701 in the registration flow is just some examples. With the evolution of the standard, the registration process in the embodiment of the present application also evolves into a corresponding process. Alternatively, the registration procedure may be replaced by any possible procedure, which is not limited.

S702, the UE determines to trigger the establishment of a session.

In case access to service 1 is desired, the UE may acquire S-nsai #1, and the identity of network 2 (optional). For example, the UE may determine that S-nsai for service 1 is S-nsai #1 and that the identity of the network deploying service 1 is the identity of network 2 (optional) based on the urs. The UE may be authenticated using S-NSSAI #1 and Allowed NSSAI. For example, the UE may determine whether the Allowed NSSAI#1 contains S-NSSAI#1 based on S-NSSAI#1. If the Allowed NSSAI#1 contains the S-NSSAI#1, the authentication passes, otherwise, the authentication fails and the execution is continued according to the existing mode.

Further, if the authentication is passed, if each S-nsai in the association relationship is unique, the UE may determine S-nsai#2 according to S-nsai#1 and the association relationship, and trigger establishment of the PDU session accordingly. Alternatively, if each S-NSSAI in the association may not be unique, the UE may determine S-NSSAI#2 from the S-NSSAI#1, the identity of the network 2, and the association, and trigger establishment of the PDU session accordingly. The specific implementation of the UE determining S-nsai#2 is similar to S505 described above, and will be understood with reference to the foregoing, and will not be described again. Or, if the UE does not obtain the identity of the network 2, for example, the identity of the network 2 is not carried in USRP, in the case that the authentication passes, the UE may determine the identity of the S-nsai#2 and the network 2 according to the S-nsai#1 and the association relationship, or the UE may determine the identity of the S-nsai#2 according to the S-nsai#1 and the association relationship, but does not determine the identity of the network 2, and the S-nsai#2 at this time is unique.

It is understood that the execution logic of the UE in S702 is merely an example and is not limited thereto. For example, after acquiring the S-nsai#1 and the identity of the network 2 (optional), the UE may also query the association relationship to determine the S-nsai#2 using the S-nsai#1 and the identity of the network 2 (optional), and then authenticate using the S-nsai#1 and the Allowed nsai.

S703, the UE sends a PDU session establishment request message to the AMF. Accordingly, the AMF receives the PDU session establishment request message from the UE.

Wherein, since the UE obtains the identifiers of the S-nsai#1, the S-nsai#2, and the network 2 (optional) in S702, the UE may carry the identifiers of the S-nsai#1, the S-nsai#2, and the network 2 (optional) in the PDU session establishment request message to request the PDU session to be established for the S-nsai#1 and the S-nsai#2, that is, the PDU session of the service 1.

It should be noted that, even if the UE determines the identity of the network 2 in S702, the UE may not carry the identity of the network 2 in S703.

S704, AMF determines SMF1 according to S-NSSAI#1 and SMF2 according to S-NSSAI#2.

The specific principle of the AMF determining SMF1 and SMF2 is similar to S505, and will be understood with reference to the foregoing, and will not be described in detail.

S705, the AMF sends the SMF2 identification to the SMF 1. Accordingly, SMF1 receives an identification of SMF2 from the AMF.

S706, SMF1 selects UPF and configures N4 session corresponding to UPF.

S707, the SMF1 transmits a PDU session creation request message to the SMF2. Accordingly, SMF2 receives the PDU session creation request message from SMF 1.

S708, SMF2 selects PSA, configures N4 session corresponding to PSA, and selects EASDF, configures DNS processing rule corresponding to EASDF.

S709, the SMF2 transmits a PDU session creation response message to the SMF 1. Accordingly, SMF1 receives the PDU session creation response message from SMF2.

S710, SMF1 and SMF2 establish a user plane connection.

S711, SMF1 sends a PDU session establishment accept message to the UE. Accordingly, the UE receives a PDU session establishment accept message from SMF 1.

The specific implementation of S705-S711 may refer to the related descriptions of S506-S512, and will not be described again.

In summary, in case the UE wants to access service 1, since the UE may provide S-nsai#1 and S-nsai#2 to the AMF, the AMF may determine SMF1 according to S-nsai#1 and SMF2 according to S-nsai#2. As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Scene 4:

fig. 8 is a schematic flow chart of a communication method according to an embodiment of the present application. Unlike scenario 3 described above, in scenario 4, the AMF may provide the UE with S-NSSAI#2 in advance, and the association of S-NSSAI#1 with S-NSSAI#2. On this basis, if the UE wants to access service 1, the UE may send S-nsai#1 and S-nsai#2 to the AMF so that the AMF determines SMF1 from S-nsai#1 and SMF2 from S-nsai#2 and the identity of network 2 (optional). As such, SMF1 and SMF2 may establish a user plane connection so that the UE may access service 1 through the PSA of network 2.

Specifically, as shown in fig. 8, the flow of the communication method is as follows:

s800, the AMF acquires the association relationship.

The specific implementation of S800 may refer to the related description in S700, and will not be repeated.

S801, the AMF sends a registration accept message to the UE. Accordingly, the UE receives a registration accept message from the AMF.

The AMF may send a registration accept message to the UE in the registration procedure, to indicate that the UE is allowed to register with the network 1. The registration accept message may include S-nsai #2, association, and Allowed nsai #2.

The specific implementation of S-nsai#2 may refer to the related description in S601, and will not be described again. The association relationship may also be carried in the same cell as the above-mentioned S-nssai#2, for example, in USRP; or, the association relationship can be independently carried in the existing cells to reduce the implementation difficulty, or the newly defined cells to improve the implementation flexibility, without limitation. The specific implementation of the Allowed nssai#2 may still refer to the related description in S601, and will not be described again. Alternatively, the Allowed NSSAI#2 may be replaced with a correspondence, such as a correspondence between the identity of the network 2 and the S-NSSAI#2, to indicate that the available slices in the network 2 include slices corresponding to the S-NSSAI#2. Of course, the correspondence may also include correspondence between the identifiers of the network 2 and other S-nsais, and the correspondence may also include correspondence between the identifiers of other networks and other S-nsais.

Continuing with the above example, one implementation of the above correspondence may be as shown in table 4 below.

TABLE 4 Table 4

Among other things, table 4 can be used to characterize: the available slices in network 1 (PLMN 1 ID) are the slices corresponding to S-NSSAI#1, S-NSSAI#3, S-NSSAI#a, and S-NSSAI#c, the available slices in network 2 (PLMN 2 ID) are the slices corresponding to S-NSSAI#2, S-NSSAI#4, and the available slices in network 3 (PLMN 3 ID) are the slices corresponding to S-NSSAI#b, S-NSSAI#d.

In addition, the specific implementation of S801 may refer to the related description in S701, which is not described herein.

S802, the UE determines to trigger the establishment of a session.

In case access to service 1 is desired, the UE may acquire S-nsai #2, and the identity of network 2 (optional). For example, the UE may determine from the urs that S-nsai for service 1 is S-nsai #2 and that the identity of the network deploying service 1 is the identity of network 2 (optional). On this basis, the UE can authenticate using S-NSSAI#2 and Allowed NSSAI#2. For example, the UE may determine whether S-NSSAI# is included in the Allowed NSSAI#2 based on S-NSSAI# 2. If the Allowed NSSAI#2 contains the S-NSSAI#2, the authentication passes, otherwise, the authentication fails and the execution is continued according to the existing mode. Alternatively, the UE may authenticate using S-nsai #2, the identity of the network 2, and the correspondence. For example, the UE may determine, according to the identifier of the network 2, that the corresponding relationship has the identifier of the corresponding network, that is, the identifier of the network 2, so as to obtain the S-NSSAI corresponding to the identifier of the network 2 in the corresponding relationship. The UE may verify that S-nsai #2 is in the S-nsai corresponding to the identity of network 2. If the identification of the network 2 corresponds to the S-NSSAI, the authentication is passed, otherwise, the authentication fails and the execution is continued according to the existing mode.

Further, if the authentication is passed, if each S-nsai in the association is unique, the UE may determine S-nsai#1 according to S-nsai#2 and the association, and trigger establishment of the PDU session accordingly. Alternatively, if each S-NSSAI in the association may not be unique, the UE may determine S-NSSAI#1 from S-NSSAI#2, the identity of network 2, and the association, and trigger establishment of the PDU session accordingly. The specific implementation of the UE determining S-nsai#1 is similar to S505 described above, and will be understood with reference to the foregoing, and will not be described again. Or, if the UE does not obtain the identity of the network 2, for example, the identity of the network 2 is not carried in USRP, in the case that the authentication passes, the UE may determine the identity of the S-nsai#1 and the network 2 according to the S-nsai#2 and the association relationship, or the UE may determine the identity of the S-nsai#1 according to the S-nsai#2 and the association relationship, but does not determine the identity of the network 2, and the S-nsai#2 at this time is unique.

S803, the UE sends a PDU session establishment request message to the AMF. Accordingly, the AMF receives the PDU session establishment request message from the UE.

The specific implementation of S803 may refer to the related description of S703, which is not described herein.

It should be noted that, even if the UE determines the identity of the network 2 in step S702, the UE may not carry the identity of the network 2 in S803.

S804, AMF determines SMF1 according to S-NSSAI#1 and SMF2 according to S-NSSAI#2.

S805, the AMF sends the SMF2 identification to the SMF 1. Accordingly, SMF1 receives an identification of SMF2 from the AMF.

S806, SMF1 selects UPF and configures N4 session corresponding to UPF.

S807, the SMF1 transmits a PDU session creation request message to the SMF2. Accordingly, SMF2 receives the PDU session creation request message from SMF 1.

S808, SMF2 selects PSA, configures N4 session corresponding to PSA, and selects EASDF, configures DNS processing rule corresponding to EASDF.

S809, the SMF2 transmits a PDU session creation response message to the SMF 1. Accordingly, SMF1 receives the PDU session creation response message from SMF2.

S810, SMF1 and SMF2 establish a user plane connection.

S811, the SMF1 sends a PDU session establishment accept message to the UE. Accordingly, the UE receives a PDU session establishment accept message from SMF 1.

The specific implementation of S805-S811 may refer to the related description of S506-S512, and will not be described again.

The flow of the communication method provided in the embodiment of the present application under various scenarios is described in detail above in connection with fig. 5 to 8. The overall flow of the communication method is described below in conjunction with fig. 9.

Fig. 9 is a schematic flow chart of the communication method. The communication method mainly relates to interaction between an access and mobility management network element and a terminal. The access and mobility management network element may specifically be an AMF in the above scenario 1-scenario 4. The terminal may specifically be a UE in scenario 1-scenario 4 described above.

As shown in fig. 9, the flow of the communication method is as follows:

s901, the terminal sends a session establishment request message to an access and mobility management network element. Correspondingly, the access and mobility management network element receives a session establishment request message from the terminal.

Wherein the access and mobility management network element may be deployed in a first network (such as network 1 described above). The first network may be a home network of the terminal and the terminal may access the home network. The second network (such as network 2 described above) may be a network other than the home network. The second network is deployed with a first service (e.g., service 1 above), which may be a service requiring session anchor access through the second network. The session establishment request message (e.g., the PDU session establishment request message described above) may include a slice identity of the first service association.

In one possible design, the slice identifier associated with the first service may be a first slice identifier of the first service in the home network (e.g., S-nsai #1 described above). In this case, before S901, the access and mobility management network element may send the first slice identifier to the terminal, and accordingly, the terminal may receive the first slice identifier from the access and mobility management network element, so as to ensure that the terminal can feed back the first slice identifier later, for example, by feeding back the first slice identifier through S901. The first slice identifier sent by the access and mobility management network element to the terminal, or the first slice identifier received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

It should be noted that, in this design, the access and mobility management network element may send not only the first slice identifier to the terminal, but also an Allowed first slice identifier list (e.g. Allowed NSSAI #1 described above) to authenticate the first slice identifier.

It can be appreciated that the specific implementation of this design scheme may also refer to the related descriptions in S502-S504, and will not be repeated.

In another possible design, the slice identifier associated with the first service may be a second slice identifier of the first service in the second network (e.g., S-nsai #2 described above). In this case, before S901, the access and mobility management network element may send the second slice identifier to the terminal, and correspondingly, the terminal may receive the second slice identifier from the access and mobility management network element, so as to ensure that the terminal can feed back the second slice identifier later. The second slice identifier sent by the access and mobility management network element to the terminal, or the second slice identifier received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation.

It should be noted that, in this design, the access and mobility management network element may send not only the second slice identifier to the terminal, but also an Allowed second slice identifier list (e.g. Allowed nssai#2 above) to the terminal, so as to authenticate the second slice identifier.

It can be appreciated that the specific implementation of this design scheme may also refer to the related descriptions in S602-S604, and will not be repeated.

Alternatively, in yet another possible design, the slice identifier of the first service association may include a first slice identifier and a second slice identifier.

In the embodiment 1, the association relationship may be an association relationship between the first slice identifier, the second slice identifier, and the identifier of the second network (e.g., the association relationship between the identifiers of the S-nsai#1, the S-nsai#2, and the network 2). Before S901, the terminal may query the association relationship according to the first slice identifier, the identifier of the second network (such as the identifier of the network 2) and the association relationship, for example, the first slice identifier and the identifier of the second network are used to determine the second slice identifier associated with the first slice identifier and the identifier of the second network, that is, the terminal determines the second slice identifier, which simplifies implementation complexity of accessing and mobility management network elements, and reduces overhead on the network side.

Optionally, before the terminal determines the second slice identifier according to the first slice identifier, the identifier of the second network and the association relationship, the terminal may locally pre-configure the first slice identifier, the identifier of the second network and the association relationship. Or before the terminal determines the second slice identifier according to the first slice identifier, the identifier of the second network and the association relationship, the access and mobility management network element can send the association relationship, the first slice identifier and the identifier of the second network to the terminal; correspondingly, the terminal may receive the association relationship between the access and the mobility management network element, the first slice identifier, and the identifier of the second network. The first slice identifier and the second network identifier sent by the access and mobility management network element to the terminal, or the first slice identifier and the second network identifier received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation. It may be appreciated that the access and mobility management network element may obtain the association relationship from the policy control network element (such as PCF) or the network slice selection network element (such as NSSF) in advance, or may also obtain the association relationship from any other possible network element, or locally pre-configure the association relationship, which may be specifically referred to the related description in S500 and will not be described herein.

In mode 2, the association relationship may be an association relationship between the first slice identifier and the second slice identifier (e.g., an association relationship between S-nsai#1 and S-nsai#2). Before S901, the terminal may query the association relationship according to the first slice identifier and the association relationship, for example, using the first slice identifier, so as to determine the second slice identifier associated with the first slice identifier conveniently, that is, to determine the second slice identifier by the terminal, so as to simplify implementation complexity of accessing and mobility management network elements, and reduce overhead on the network side.

Optionally, before the terminal determines the second slice identifier according to the first slice identifier and the association relationship, the terminal may locally preconfigure the first slice identifier and the association relationship. Or before the terminal determines the second slice identifier according to the first slice identifier and the association relationship, the access and mobility management network element can send the association relationship and the first slice identifier to the terminal; correspondingly, the terminal may receive the association relationship between the access and the mobility management network element and the first slice identifier. The first slice identifier sent by the access and mobility management network element to the terminal, or the first slice identifier received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation. It may be understood that the access and mobility management network element may obtain the association relationship from the policy control network element or the network slice selection network element in advance, or may also obtain the association relationship from any other possible network element, or locally pre-configure the association relationship, and specifically, reference may also be made to the related description in S500 above, which is not repeated.

It should be noted that, in the difference between the embodiment 1 and the embodiment 2, since, for the embodiment 1, the slice identifier of a service in the other networks (networks other than the first network and the second network) may be the same as the second slice identifier, that is, the second slice identifier is a non-unique identifier, the access and mobility management network element may provide the identifier of the second network to the terminal to distinguish the same slice identifiers, so as to ensure that the terminal can determine the second slice identifier, and not the slice identifiers of the other networks. For mode 2, if the slice identifier of a service in another network (networks other than the first network and the second network) is the same as the second slice identifier, that is, the second slice identifier is a unique identifier, the access and mobility management network element may not provide an association relationship between the network and the slice identifier, so as to save overhead and improve communication efficiency. And, the terminal also can not consider the identification of the second network when determining the second slice identification, so that the processing logic is simpler.

It will also be appreciated that in modes 1 and 2, the access and mobility management network element may also send an allowed first slice identity list to the terminal for authentication of the first slice identity. In addition, the specific implementation of the modes 1 and 2 may refer to the related description in the above-mentioned S701-S703, and will not be repeated.

In mode 3, before S901, the association relationship may be an association relationship of the first slice identifier, the second slice identifier, and the identifier of the second network. The terminal can query the association relationship according to the second slice identifier, the identifier of the second network and the association relationship, for example, the second slice identifier and the identifier of the second network are used to conveniently determine the first slice identifier associated with the second slice identifier and the identifier of the second network, that is, the terminal determines the first slice identifier, so that the implementation complexity of accessing and mobility management network elements is simplified, and the cost of the network side is reduced.

Optionally, before the terminal determines the first slice identifier according to the second slice identifier, the identifier of the second network and the association relationship, the terminal may locally pre-configure the second slice identifier, the identifier of the second network and the association relationship. Or before the terminal determines the first slice identifier according to the second slice identifier, the identifier of the second network and the association relationship, the access and mobility management network element can send the association relationship, the second slice identifier and the identifier of the second network to the terminal; correspondingly, the terminal receives the association relation between the access and the mobility management network element, the second slice identifier and the identifier of the second network. The second slice identifier and the identifier of the second network sent by the access and mobility management network element to the terminal, or the second slice identifier and the identifier of the second network received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation. It can be understood that the manner of acquiring the association relationship between the access and the mobility management network element is similar to the manner 1, and reference is made to understanding, and details are not repeated.

In the mode 4, the association relationship may be an association relationship between the first slice identifier and the second slice identifier. Before S901, the terminal may query the association relationship according to the second slice identifier and the association relationship, for example, using the second slice identifier, so as to determine the first slice identifier associated with the second slice identifier conveniently, that is, to determine the first slice identifier by the terminal, so as to simplify implementation complexity of accessing and mobility management network elements, and reduce overhead on the network side.

Optionally, before the terminal determines the first slice identifier according to the second slice identifier and the association relationship, the terminal may locally preconfigure the second slice identifier and the association relationship. Or before the terminal determines the first slice identifier according to the second slice identifier and the association relationship, the access and mobility management network element can send the association relationship and the identifier of the second network to the terminal; correspondingly, the terminal receives the association relation between the access and the mobility management network element and the identification of the second network. The second slice identifier sent by the access and mobility management network element to the terminal, or the second slice identifier received by the terminal from the access and mobility management network element, may be carried in the urs of the terminal, that is, in an existing cell, so as to reduce implementation difficulty, or may also be carried in a new cell, so as to improve implementation flexibility, without limitation. It can be understood that the manner of acquiring the association relationship between the access and the mobility management network element is similar to the manner 2, and reference is made to understanding, and details are not repeated.

It should be noted that, in the manner 3, the difference from the manner 4 is that, in the manner 3, since the second slice identifier is a non-unique identifier, the access and mobility management network element may provide the identifier of the second network to the terminal, so as to distinguish these same slice identifiers, so as to ensure that the terminal can determine the first slice identifier, but not the slice identifiers of other networks. For mode 4, if the second slice identifier is a unique identifier, the access and mobility management network element may not provide an association relationship between the network and the slice identifier, so as to save overhead and improve communication efficiency. And, the terminal can also not consider the identification of the second network when determining the first slice identification, so that the processing logic is simpler.

It will also be appreciated that in modes 3 and 4, the access and mobility management network element may also send a list of allowed second slice identities to the terminal for authentication of the second slice identities. In addition, the specific implementation of the modes 3 and 4 may refer to the related descriptions in the above S801-S803, and will not be repeated.

S902, the access and mobility management network element determines a second session management network element in the second network according to the slice identifier associated with the first service.

One possible design is that the slice identifier associated with the first service is the first slice identifier. In this case, the access and mobility management network element may determine the second session management network element according to the first slice identifier. This ensures that the second session management network element can support the slice corresponding to the first service.

The access and mobility management network element may determine, according to the first slice identifier, a second slice identifier of the first service in the second network and an identifier of the second network. Optionally, the association relationship is an association relationship of the first slice identifier, the second slice identifier and the identifier of the second network. In this case, the access and mobility management network element may determine the second slice identifier and the identifier of the second network according to the first slice identifier and the association relationship. For example, the access and mobility management network element may query the association relationship using the first slice identity to facilitate determining a second slice identity associated with the first slice identity and an identity of the second network. Thereafter, the access and mobility management network element may determine a second session management network element based on the second slice identity and the identity of the second network. It will be appreciated that since the slice identity of a service in other networks (networks other than the first and second networks) may be the same as the second slice identity, i.e. the second slice identity is a non-unique identity, the access and mobility management network element may use the identity of the second network to distinguish between these same slice identities to ensure that a second session management network element within the second network can be selected instead of the session management network elements of the other networks.

Alternatively, the access and mobility management network element may determine a second slice identifier of the first service in the second network according to the first slice identifier. Optionally, the association relationship is an association relationship between the first slice identifier and the second slice identifier. In this case, the access and mobility management network element may determine the second slice identifier according to the first slice identifier and the association relationship. For example, the access and mobility management network element may query the association relationship using the first slice identity to facilitate determining a second slice identity associated with the first slice identity. Thereafter, the access and mobility management network element may determine a second session management network element based on the second slice identifier. It will be appreciated that if the slice identity of no service in the other networks (networks other than the first network and the second network) is the same as the second slice identity, i.e. the second identity is a unique identity, then the access and mobility management network element may not take into account the identity of the second network when selecting the second session management network element, so that the processing logic is simpler.

Optionally, before the access and mobility management network element determines the second session management network element according to the first slice identifier, the access and mobility management network element may further determine that the first slice list (e.g. the above-mentioned S-nsai list 1) includes the first slice identifier. Wherein the slice identifier in the first slice list is a slice identifier of the service deployed by the second network in the home network. In other words, the access and mobility management network element may determine that the slice identity is the slice identity of traffic deployed in the other network mapped to the home network in order to properly select session management network elements located within the other network.

Optionally, the access and mobility management element may further determine a first session management element (e.g. SMF1 described above) within the home network according to the first slice identity, where the first session management element may be used to establish a user plane connection of the terminal to the PSA of the second network, ensuring that the terminal may access the first service through the PSA.

It can be appreciated that the specific implementation of this design scheme is also referred to the above description of S500-S502 and S505, and will not be repeated.

In another possible embodiment, the slice identifier of the first service association is a second slice identifier. In this case, the access and mobility management element may determine the second session management element according to the second slice identifier and the identifier of the second network. That is, since the slice identity of a certain service in other networks (networks other than the first network and the second network) may be identical to the second slice identity, the access and mobility management network element may use the identity of the second network to distinguish these identical slice identities to ensure that a second session management network element within the second network can be selected instead of the session management network elements of the other networks. Alternatively, the access and mobility management network element may determine the second session management network element according to the second slice identifier. That is, if the second slice identity is a unique identity, the access and mobility management network element may not take into account the identity of the second network when selecting the second session management network element, so that the processing logic is simpler.

Optionally, before the access and mobility management network element determines the second session management network element, the access and mobility management network element may further determine that the second slice list (e.g. the above-mentioned S-NSSAI list 2) contains a second slice identifier. Wherein the slice identifier in the second slice list is a slice identifier of the service deployed by the second network within the second network. In other words, the access and mobility management network element may determine that the slice identifier is a slice identifier of traffic deployed in the other network in order to properly select a session management network element located in the other network.

Optionally, the access and mobility management element may further determine a first session management element within the home network according to the second slice identifier, where the first session management element may be used to establish a user plane connection of the terminal to a PSA of the second network, to ensure that the terminal may access the first service through the PSA.

The access and mobility management network element may determine the first slice identifier according to the second slice identifier and the identifier of the second network. That is, if the second slice identity is a non-unique identity, the access and mobility management network element may use the identity of the second network to distinguish between these same slice identities to ensure that the first slice identity can ultimately be determined, but not the slice identities of the other networks. For example, the association relationship is an association relationship of the first slice identifier, the second slice identifier, and the identifier of the second network. The access and mobility management network element may query the association according to the second slice identifier, the identifier of the second network, and the association, for example, using the second slice identifier and the identifier of the second network, so as to conveniently determine the first slice identifier associated with the second slice identifier and the identifier of the second network. The access and mobility management network element may then determine the first session management network element based on the first slice identifier.

Alternatively, the access and mobility management network element may determine the first slice identifier from the second slice identifier. That is, if the second slice identity is a unique identity, the access and mobility management network element may not consider the identity of the second network when determining the first slice identity, so that the processing logic is simpler. For example, the association relationship is an association relationship of the first slice identifier and the second slice identifier. The access and mobility management network element may query the association according to the second slice identifier and the association, for example, using the second slice identifier, so as to conveniently determine the first slice identifier associated with the second slice identifier. The access and mobility management network element may then determine the first session management network element based on the first slice identifier.

It will be appreciated that the specific implementation of this design is also referred to the above description of S600-S602 and S605, and will not be repeated.

In a further possible embodiment, the slice identifier associated with the first service comprises a first slice identifier and a second slice identifier. In this case, the access and mobility management network element may determine the first session management network element based on the first slice identifier. The access and mobility management network element can determine a second session management network element according to the second slice identifier and the identifier of the second network; alternatively, the access and mobility management network element may determine the second session management network element according to the second slice identifier, i.e. if the second slice identifier is a unique identifier, the access and mobility management network element may not consider the identifier of the second network when determining the second session management network element, so that the processing logic is simpler.

It will be appreciated that since the second session management network element is operable to select the PSA of the first service on the second network, the first session management network element is operable to establish a user plane connection of the terminal to the PSA, thus ensuring that the terminal can access the first service via the PSA.

It can be appreciated that the specific implementation of this design scheme may refer to the relevant descriptions in S700-S701 and S704 or S800-S801 and S804, and will not be repeated.

S903, the access and mobility management network element sends a session establishment acceptance message to the terminal. Correspondingly, the terminal receives a session establishment acceptance message from the access and mobility management network element.

The session establishment acceptance message is used to indicate that the second network has established a session for accessing the first service for the terminal, and the description of the session establishment acceptance message in S506-S512 may be referred to, which is not repeated.

In summary, when the first service is deployed in the second network and the terminal accesses the home network, the access and mobility management network element of the home network can select a second session management network element in the second network for the first service based on the slice identifier associated with the first service, so that the second session management network element can establish a session of the first service for the terminal, for example, select a session anchor point of the first service in the second network, for example, a protocol data unit session anchor PSA, so that the terminal can access the first service through the PSA, and the terminal accessing the home network can still access the service deployed in other operator networks. For example, in the case where the first service is a service that needs to be accessed through a session anchor point of the second network, it may be further implemented that in the case where the service does not support PSA access of other operators, the other operators, such as a terminal of the home network, can still access the service.

The communication method provided in the embodiment of the present application is described in detail above with reference to fig. 5 to 9. A communication apparatus for performing the communication method provided in the embodiment of the present application is described in detail below with reference to fig. 10 to 11.

Fig. 10 is a schematic structural diagram of a communication device according to an embodiment of the present application. As shown in fig. 10, the communication apparatus 1000 includes: a transceiver module 1001 and a processing module 1002. For convenience of explanation, fig. 10 shows only major components of the communication apparatus.

In some embodiments, the communication apparatus 1000 may be adapted for use in the communication system shown in fig. 4, performing the functions of the AMF or access and mobility management network element described above.

The transceiver module 1001 may be configured to perform functions of AMF or access and mobility management network element for receiving and sending messages, such as the functions in steps S504, S506, S901, etc. The processing module 1002 may perform functions of the AMF or the access and mobility management network element other than sending and receiving messages, such as the functions in the steps S505, S902 and so on described above. For example, the transceiver module 1001 is configured to receive a session establishment request message from a terminal. The communication device 1000 is disposed in a first network, where the first network is a home network of a terminal, and the terminal accesses the home network. The session establishment request message includes a slice identity associated with a first service deployed by a second network, the second network being a network other than the home network. In this way, the processing module 1002 is configured to determine, according to the slice identifier, a second session management network element in the second network, where the second session management network element is configured to establish a session for the terminal to access the first service.

Alternatively, the transceiver module 1001 may include a transmitting module and a receiving module. The transmitting module is configured to implement a transmitting function of the communication device 1000, and the receiving module is configured to implement a receiving function of the communication device 1000.

Optionally, the communication device 1000 may further include a storage module, where a program or instructions are stored. The processing module 1002, when executing the program or instructions, enables the communication device 1000 to perform the communication method described above.

The communication apparatus 1000 may be a network device, a chip (system) or other components or assemblies that may be provided in the network device, or an apparatus including the network device, which is not limited in this application.

In addition, the technical effects of the communication apparatus 1000 may refer to the technical effects of the above-mentioned communication method, and will not be described herein.

In other embodiments, the communication apparatus 1000 may be adapted for use in the communication system shown in fig. 4 to perform the functions of the UE or terminal described above.

The transceiver module 1001 may be configured to perform a function of transmitting and receiving a message by a UE or a terminal, such as the functions in steps S502, S504, S901, and the like. The processing module 1002 may perform functions of the UE or terminal other than transmitting and receiving messages, such as the functions in the step S503 and the like. For example, the number of the cells to be processed,

A processing module 1002, configured to control the transceiver module 1001 to send a session establishment request message to an access and mobility management network element. Wherein the access and mobility management network element is deployed in a first network, the first network being a home network of the communication device 1000, the communication device 1000 accessing the home network, the session establishment request message comprising a slice identity associated with a first service deployed in a second network, the second network being a network other than the home network. As such, the transceiver module 1001 is configured to receive a session establishment acceptance message from the access and mobility management network element, where the session establishment acceptance message is used to indicate that the second network has established a session for the communication device 1000 for accessing the first service.

The communication device 1000 may be a terminal, a chip (system) or other components or modules that may be provided in the terminal, or a device including a terminal, which is not limited in this application.

Fig. 11 is a schematic diagram of a second configuration of a communication device according to an embodiment of the present application. The communication device may be a terminal, or may be a chip (system) or other part or component that may be provided in the terminal. As shown in fig. 11, the communication device 1100 may include a processor 1101. Optionally, the communication device 1100 may also include memory 1102 and/or a transceiver 1103. The processor 1101 is coupled to the memory 1102 and the transceiver 1103, as may be connected by a communication bus.

The following describes the respective constituent elements of the communication apparatus 1100 in detail with reference to fig. 11:

the processor 1101 is a control center of the communication device 1100, and may be one processor or a collective term of a plurality of processing elements. For example, the processor 1101 is one or more central processing units (central processing unit, CPU), but may also be an integrated circuit (application specific integrated circuit, ASIC), or one or more integrated circuits configured to implement embodiments of the present application, such as: one or more microprocessors (digital signal processor, DSPs), or one or more field programmable gate arrays (field programmable gate array, FPGAs).

Alternatively, the processor 1101 may perform various functions of the communication apparatus 1100, such as performing the communication methods shown in fig. 8-10 described above, by running or executing a software program stored in the memory 1102 and invoking data stored in the memory 1102.

In a particular implementation, the processor 1101 may include one or more CPUs, such as CPU0 and CPU1 shown in FIG. 11, as an embodiment.

In a specific implementation, as an embodiment, the communication device 1100 may also include multiple processors, such as the processor 1101 and the processor 1104 shown in fig. 11. Each of these processors may be a single-core processor (single-CPU) or a multi-core processor (multi-CPU). A processor herein may refer to one or more devices, circuits, and/or processing cores for processing data (e.g., computer program instructions).

The memory 1102 is configured to store a software program for executing the present application, and is controlled to execute by the processor 1101, and the specific implementation may refer to the above method embodiment, which is not described herein again.

Alternatively, memory 1102 may be, but is not limited to, read-only memory (ROM) or other type of static storage device that can store static information and instructions, random access memory (random access memory, RAM) or other type of dynamic storage device that can store information and instructions, but may also be electrically erasable programmable read-only memory (electrically erasable programmable read-only memory, EEPROM), compact disc read-only memory (compact disc read-only memory) or other optical disk storage, optical disk storage (including compact disc, laser disc, optical disc, digital versatile disc, blu-ray disc, etc.), magnetic disk storage media or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. The memory 1102 may be integrated with the processor 1101, may exist separately, and may be coupled to the processor 1101 through an interface circuit (not shown in fig. 11) of the communication device 1100, which is not specifically limited by the embodiments of the present application.

A transceiver 1103 for communication with other communication devices. For example, the communication apparatus 1100 is a terminal, and the transceiver 1103 may be used to communicate with a network device or another terminal device. As another example, the communication apparatus 1100 is a network device, and the transceiver 1103 may be used to communicate with a terminal or another network device.

Alternatively, the transceiver 1103 may include a receiver and a transmitter (not separately shown in fig. 11). The receiver is used for realizing the receiving function, and the transmitter is used for realizing the transmitting function.

Alternatively, the transceiver 1103 may be integrated with the processor 1101, or may exist separately, and be coupled to the processor 1101 through an interface circuit (not shown in fig. 11) of the communication device 1100, which is not specifically limited by the embodiment of the present application.

It should be noted that the configuration of the communication device 1100 shown in fig. 11 is not limited to the communication device, and an actual communication device may include more or less components than those shown, or may combine some components, or may be different in arrangement of components.

In addition, the technical effects of the communication device 1100 may refer to the technical effects of the communication method described in the above method embodiments, which are not described herein.

The embodiment of the application provides a communication system. The communication system may include: UE, AMF, SMF1, SMF2, UPF, and/or PSA, etc. shown in fig. 5-8, which are used in conjunction to perform the method flows shown in any of fig. 5-8. Alternatively, the communication system may include: the terminal and/or access and mobility management network elements shown in fig. 9 are adapted to cooperate in performing the method flow shown in fig. 9.

It should be appreciated that the processor in embodiments of the present application may be a central processing unit (central processing unit, CPU), which may also be other general purpose processors, digital signal processors (digital signal processor, DSP), application specific integrated circuits (application specific integrated circuit, ASIC), off-the-shelf programmable gate arrays (field programmable gate array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or the like. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like.

It should also be appreciated that the memory in embodiments of the present application may be either volatile memory or nonvolatile memory, or may include both volatile and nonvolatile memory. The nonvolatile memory may be a read-only memory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), an electrically Erasable EPROM (EEPROM), or a flash memory. The volatile memory may be random access memory (random access memory, RAM) which acts as an external cache. By way of example but not limitation, many forms of random access memory (random access memory, RAM) are available, such as Static RAM (SRAM), dynamic Random Access Memory (DRAM), synchronous Dynamic Random Access Memory (SDRAM), double data rate synchronous dynamic random access memory (DDR SDRAM), enhanced Synchronous Dynamic Random Access Memory (ESDRAM), synchronous Link DRAM (SLDRAM), and direct memory bus RAM (DR RAM).

The above embodiments may be implemented in whole or in part by software, hardware (e.g., circuitry), firmware, or any other combination. When implemented in software, the above-described embodiments may be implemented in whole or in part in the form of a computer program product. The computer program product comprises one or more computer instructions or computer programs. When the computer instructions or computer program are loaded or executed on a computer, the processes or functions described in accordance with the embodiments of the present application are all or partially produced. The computer may be a general purpose computer, a special purpose computer, a computer network, or other programmable apparatus. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer instructions may be transmitted from one website site, computer, server, or data center to another website site, computer, server, or data center by wired (e.g., infrared, wireless, microwave, etc.). The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains one or more sets of available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium. The semiconductor medium may be a solid state disk.

It should be understood that the term "and/or" is merely an association relationship describing the associated object, and means that three relationships may exist, for example, a and/or B may mean: there are three cases, a alone, a and B together, and B alone, wherein a, B may be singular or plural. In addition, the character "/" herein generally indicates that the associated object is an "or" relationship, but may also indicate an "and/or" relationship, and may be understood by referring to the context.

In the present application, "at least one" means one or more, and "a plurality" means two or more. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a-b, a-c, b-c, or a-b-c, wherein a, b, c may be single or plural.

It should be understood that, in various embodiments of the present application, the sequence numbers of the foregoing processes do not mean the order of execution, and the order of execution of the processes should be determined by the functions and internal logic thereof, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.

It will be clear to those skilled in the art that, for convenience and brevity of description, specific working procedures of the above-described systems, apparatuses and units may refer to corresponding procedures in the foregoing method embodiments, and are not repeated herein.

In the several embodiments provided in this application, it should be understood that the disclosed systems, devices, and methods may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of the units is merely a logical function division, and there may be additional divisions when actually implemented, e.g., multiple units or components may be combined or integrated into another system, or some features may be omitted or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical or other form.

The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit.

The functions, if implemented in the form of software functional units and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a read-only memory (ROM), a random access memory (random access memory, RAM), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about changes or substitutions within the technical scope of the present application, and the changes and substitutions are intended to be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method of communication, the method comprising:

an access and mobility management network element receives a session establishment request message from a terminal, wherein the access and mobility management network element is deployed in a first network, the first network is a home network of the terminal, the terminal is accessed to the home network, the session establishment request message comprises a slice identifier associated with a first service deployed in a second network, and the second network is a network other than the home network;

and the access and mobility management network element determines a second session management network element in the second network according to the slice identifier, wherein the second session management network element is used for establishing a session for accessing the first service for the terminal.

2. The method of claim 1, wherein the slice identifier is a first slice identifier of the first service in the home network, and wherein the access and mobility management network element determines a second session management network element in the second network based on the slice identifier, comprising:

and the access and mobility management network element determines the second session management network element according to the first slice identifier.

3. The method according to claim 2, wherein the determining, by the access and mobility management network element, the second session management network element based on the first slice identifier, comprises:

the access and mobility management network element determines a second slice identifier of the first service in the second network and an identifier of the second network according to the first slice identifier;

and the access and mobility management network element determines the second session management network element according to the second slice identifier and the identifier of the second network.

4. A method according to claim 3, wherein the access and mobility management network element determining a second slice identity of the first traffic at the second network and an identity of the second network based on the first slice identity comprises:

And the access and mobility management network element determines the second slice identifier and the identifier of the second network according to the first slice identifier and the association relationship, wherein the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

5. The method according to any of claims 2-4, wherein before the access and mobility management network element determines the second session management network element from the first slice identity, the method further comprises:

the access and mobility management network element determines that a first slice list contains the first slice identifier, wherein the slice identifier in the first slice list is the slice identifier of the service deployed by the second network in the home network.

6. The method according to any one of claims 2-5, further comprising:

the access and mobility management network element determines a first session management network element within the home network according to the first slice identifier.

7. The method according to any of claims 2-6, characterized in that before the access and mobility management network element receives a session establishment request message from a terminal, the method further comprises:

And the access and mobility management network element sends the first slice identifier to the terminal.

8. The method of claim 1, wherein the slice identifier is a second slice identifier of the first service in the second network, and wherein the determining, by the access and mobility management network element, a second session management network element in the second network according to the slice identifier comprises:

9. The method of claim 8, wherein prior to the access and mobility management network element determining the second session management network element based on the second slice identity and the identity of the second network, the method further comprises:

the access and mobility management network element determines that a second slice list contains the second slice identifier, wherein the slice identifier in the second slice list is the slice identifier of the service deployed by the second network in the second network.

10. The method according to claim 8 or 9, characterized in that the method further comprises:

And the access and mobility management network element determines a first session management network element in the home network according to the second slice identifier.

11. The method of claim 10, wherein the access and mobility management network element determining a first session management network element within the home network based on the second slice identity comprises:

the access and mobility management network element determines a first slice identifier of the first service in the home network according to the second slice identifier and the identifier of the second network;

and the access and mobility management network element determines the first session management network element according to the first slice identifier.

12. The method of claim 11, wherein the determining, by the access and mobility management network element, the first slice identity of the first service at the home network based on the second slice identity and the identity of the second network comprises:

the access and mobility management network element determines the first slice identifier according to the second slice identifier, the identifier of the second network and the association relationship, wherein the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

13. The method according to any of claims 8-12, characterized in that before the access and mobility management network element receives a session establishment request message from a terminal, the method further comprises:

and the access and mobility management network element sends the second slice identifier to the terminal.

14. The method of claim 1, wherein the slice identifier comprises a first slice identifier of the first service at the home network and a second slice identifier of the first service at the second network, wherein the access and mobility management network element determines a second session management network element within the second network based on the slice identifier, comprising:

the access and mobility management network element determines a first session management network element in the home network according to the first slice identifier, and determines the second session management network element according to the second slice identifier and the identifier of the second network.

15. The method according to claim 14, characterized in that before the access and mobility management network element receives the session establishment request message from the terminal, the method further comprises:

The access and mobility management network element sends an association relationship, the first slice identifier and the identifier of the second network to the terminal, wherein the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

16. The method according to claim 14, characterized in that before the access and mobility management network element receives the session establishment request message from the terminal, the method further comprises:

the access and mobility management network element sends an association relationship, the second slice identifier and the identifier of the second network to the terminal, wherein the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

17. The method according to claim 3, 11 or 15, characterized in that the method further comprises:

and the access and mobility management network element obtains the association relation from a strategy control network element or a network slice selection network element.

18. The method according to any of claims 1-17, wherein the first traffic is traffic requiring session anchor access through the second network.

19. A method of communication, the method comprising:

a terminal sends a session establishment request message to an access and mobility management network element, wherein the access and mobility management network element is deployed in a first network, the first network is a home network of the terminal, the terminal is accessed to the home network, the session establishment request message comprises a slice identifier associated with a first service deployed in a second network, and the second network is a network other than the home network;

the terminal receives a session establishment acceptance message from the access and mobility management network element, wherein the session establishment acceptance message is used for indicating that the second network has established a session for the terminal for accessing the first service.

20. The method of claim 19, wherein the slice identity is a first slice identity of the first service at the home network, the method further comprising, prior to the terminal sending a session establishment request message to an access and mobility management network element:

the terminal receives the first slice identifier from the access and mobility management network element.

21. The method of claim 19, wherein the slice identity is a second slice identity of the first service at the second network, and wherein the method further comprises, prior to the terminal sending a session establishment request message to an access and mobility management network element:

The terminal receives the second slice identifier from the access and mobility management network element.

22. The method of claim 19, wherein the slice identity comprises a first slice identity of the first service at the home network and a second slice identity of the first service at the second network, the method further comprising, prior to the terminal sending a session establishment request message to an access and mobility management network element:

the terminal determines the second slice identifier according to the first slice identifier, the identifier of the second network and the association relation; the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

23. The method of claim 22, wherein prior to the terminal determining the second slice identity based on the first slice identity, the identity of the second network, and the association, the method further comprises:

the terminal receives the association relation between the access and the mobility management network element, the first slice identifier and the identifier of the second network.

24. The method of claim 19, wherein the slice identity comprises a first slice identity of the first service at the home network and a second slice identity of the first service at the second network, the method further comprising, prior to the terminal sending a session establishment request message to an access and mobility management network element:

the terminal determines the first slice identifier according to the second slice identifier, the identifier of the second network and the association relation; the association relationship is that of the first slice identifier, the second slice identifier and the identifier of the second network.

25. The method of claim 24, wherein the determining, by the terminal, the first slice identifier according to the second slice identifier, the identifier of the second network, and the association relation, comprises:

the terminal receives the association relation between the access and the mobility management network element, the second slice identifier and the identifier of the second network.

26. A communication device, the device comprising: one or more modules for performing the method of any of claims 1-25.

27. A communication device, the communication device comprising: a processor and a memory; the memory is configured to store computer instructions that, when executed by the processor, cause the communication device to perform the communication method of any of claims 1-25.

28. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a computer program or instructions which, when run on a computer, cause the computer to perform the communication method according to any one of claims 1-25.