WO2020108541A1

WO2020108541A1 - Method and apparatus for protocol prefix management

Info

Publication number: WO2020108541A1
Application number: PCT/CN2019/121326
Authority: WO
Inventors: Chunmiao LIU; Yingjiao HE; Wen Zhang
Original assignee: Telefonaktiebolaget Lm Ericsson (Publ)
Priority date: 2018-11-30
Filing date: 2019-11-27
Publication date: 2020-06-04

Abstract

A method for protocol prefix management is proposed. The method which may be performed by a first network node comprises determining capability information of the first network node to indicate that the first network node supports a capability of protocol prefix management for a terminal device. The method further comprises transmitting the capability information to a second network node. According to the embodiments of the present disclosure, the protocol prefix management can be implemented adaptively and flexibly, so that network function deployment and resource efficiency can be improved.

Description

METHOD AND APPARATUS FOR PROTOCOL PREFIX MANAGEMENT

FIELD OF THE INVENTION

The present disclosure generally relates to communication networks, and more specifically, to protocol prefix management in a communication network.

BACKGROUND

This section introduces aspects that may facilitate a better understanding of the disclosure. Accordingly, the statements of this section are to be read in this light and are not to be understood as admissions about what is in the prior art or what is not in the prior art.

Communication service providers and network operators have been continually facing challenges to deliver value and convenience to consumers by, for example, providing compelling network services and performance. With the rapid development of networking and communication technologies, wireless communication networks such as long-term evolution (LTE) /fourth generation (4G) network and new radio (NR) /fifth generation (5G) network are expected to achieve high traffic capacity and end-user data rate with lower latency. To meet the diverse requirements of new services across a wide variety of industries, the 3rd generation partnership project (3GPP) is developing the core network architecture with control and user plane separation (CUPS) techniques. CUPS can provide the architecture enhancements for the separation of functionality in the evolved packet core (EPC) , for example, for a serving gateway (SGW) , a packet data network gateway (PGW) and a traffic detection function (TDF) . This enables flexible network deployment and operation, by distributed or centralized deployment and the independent scaling between control plane (CP) and user plane (UP) functions. However, the handling of tunnels between CP and UP may complicate exchange of signaling such as Internet protocol version 6 (IPv6) management messages. Thus, it is desirable to improve the transmission efficiency of signaling messages.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

Packets in a wireless communication network may have an IP address for routing the packets to an intended wireless device such as user equipment (UE) . An Sx-u tunnel between CP and UP needs to be introduced for the IPv6 router solicitation/router advertisement (RS/RA) and other dynamic host configuration protocol for IPv6 (DHCPv6) related configuration messages transferring between UE and CP. In addition, another standalone Sx-u tunnel between CP and UP for DHCP also needs to be introduced when an external DHCPv4/v6 server is reachable only via a PGW user plane function (PGW-U) or a user plane function (UPF) . The tunnel handling in PGW control plane function/user plane function (PGW-C/U) may complicate the network structure, increase the deployment cost and degrade the transmission efficiency. Therefore, it may be desirable to improve node function allocation in the network.

The present disclosure proposes a solution of protocol prefix management in a communication network, which can enable a network node such as PGW-U to activate a server/proxy function for protocol prefix management (such as IPv6 prefix management) , so that the Sx-u tunnels used to transfer IPv6 management messages may not be needed in 4G CUPS and 5G core (5GC) .

According to a first aspect of the present disclosure, there is provided a method performed by a first network node such as a PGW-U. The method comprises determining capability information of the first network node. The capability information indicates that the first network node supports a capability of protocol prefix management for a terminal device. The method further comprises transmitting the capability information to a second network node such as PGW-C.

In accordance with an exemplary embodiment, the capability of the protocol prefix management may comprise at least one of a server function and a proxy function for the protocol prefix management. In accordance with an exemplary embodiment, the protocol prefix management may comprise IPv6 prefix management.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: receiving an activation instruction from the second network node. The activation instruction may indicate the first network node to enable the capability of the protocol prefix management for the terminal device.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: enabling a server function for the protocol prefix management of the first network node, in response to reception of the activation instruction indicating the first network node to enable the server function for the protocol prefix management.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: obtaining a protocol prefix allocated to the terminal device from the second network node.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: enabling a proxy function for the protocol prefix management of the first network node, in response to reception of the activation instruction indicating the first network node to enable the proxy function for the protocol prefix management.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: obtaining an indicator of a network instance (e.g., for an access point name (APN) or a data network (DN) ) for the terminal device from the second network node.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: sending a request for a protocol prefix for the terminal device to a server which is able to allocate the protocol prefix to the terminal device; and obtaining the protocol prefix allocated to the terminal device from the server.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: transmitting the protocol prefix allocated to the terminal device to the second network node.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: providing protocol interface information for the terminal device to the second network node.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: receiving a request for prefix allocation information from the terminal device; and transmitting the prefix allocation information to the terminal device. The prefix allocation information may comprise the protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the prefix allocation information may further comprise one or more protocol configuration parameters for the terminal device. Optionally, the one or more protocol configuration parameters may be provisioned by at least one of: the first network node; the second network node; and a server which allocates the protocol prefix to the terminal device.

In accordance with an exemplary embodiment where the first network node enables the capability of the protocol prefix management to act as a protocol prefix management server for the terminal device, the one or more protocol configuration parameters related to the protocol prefix of the terminal device may be provisioned by the first network node locally. Alternatively or additionally, the first network node may acquire at least part of the one or more protocol configuration parameters from the second network node. Optionally, the second network node may obtain at least part of the one or more protocol configuration parameters from the server which allocates the protocol prefix to the terminal device.

In accordance with an exemplary embodiment where the first network node enables the capability of the protocol prefix management to act as a protocol prefix management proxy for the terminal device, the one or more protocol configuration parameters may be provisioned by the server which allocates the protocol prefix to the terminal device, and obtained by the first network node from this server.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: renewing the protocol prefix allocated to the terminal device by sending prefix renewal information to the terminal device.

In accordance with an exemplary embodiment, the prefix renewal information may be provisioned by at least one of: the first network node; the second network node; and a server which allocates the protocol prefix to the terminal device. Optionally, the protocol prefix allocated to the terminal device may comprise a protocol prefix for a packet data network (PDN) connection. For example, in the case that the first network node enables the server function for the protocol prefix management, the prefix renewal information may be provisioned by the first network node locally. Alternatively or additionally, the first network node may acquire at least part of the prefix renewal information from the second network node. Optionally, the second network node may obtain at least part of the prefix renewal information from the server which allocates the protocol prefix to the terminal device. In the case that the first network node enables the proxy function for the protocol prefix management, the prefix renewal information may be provisioned by the server which allocates the protocol prefix to the terminal device, and obtained by the first network node from this server.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: receiving a request for prefix delegation information from the terminal device; and transmitting the prefix delegation information to the terminal device. The prefix delegation information may comprise a delegating prefix for the terminal device.

In accordance with an exemplary embodiment, the delegating prefix for the terminal device may be obtained by the first network node from the second network node, or a server which is able to allocate the delegating prefix to the terminal device. Optionally, the prefix delegation information may indicate the protocol prefix for the PDN connection as an excluded prefix.

In accordance with an exemplary embodiment, the method according to the first aspect of the present disclosure may further comprise: receiving a deactivation instruction from the second network node. The deactivation instruction indicates the first network node to disable the enabled capability of the protocol prefix management for the terminal device. The method according to the first aspect of the present disclosure may further comprise: disabling the enabled capability of the protocol prefix management for the terminal device according to the deactivation instruction.

According to a second aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the first aspect of the present disclosure.

According to a third aspect of the present disclosure, there is provided a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the method according to the first aspect of the present disclosure.

According to a fourth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise a determining unit and a transmitting unit. In accordance with some exemplary embodiments, the determining unit may be operable to carry out at least the determining step of the method according to the first aspect of the present disclosure. The transmitting unit may be operable to carry out at least the transmitting step of the method according to the first aspect of the present disclosure.

According to a fifth aspect of the present disclosure, there is provided a method performed by a second network node such as a PGW-C. The method comprises receiving capability information from a first network node such as a PGW-U. The capability information may indicate that the first network node supports a capability (e.g., a server/proxy function) of protocol prefix management for a terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: determining, based at least in part on the capability information, whether to enable the capability of the protocol prefix management of the first network node.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: transmitting an activation instruction to the first network node to indicate the first network node to enable a proxy function for the protocol prefix management, in response to determination of enabling the proxy function of the first network node for the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: providing an indicator of a network instance for the terminal device to the first network node.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: informing the first network node of an identifier (e.g., address, name, number and etc. ) of a server which is able to allocate a protocol prefix to the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: receiving a protocol prefix allocated to the terminal device from the first network node.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: transmitting an activation instruction to the first network node to indicate the first network node to enable a server function for the protocol prefix management, in response to determination of enabling the server function of the first network node for the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: providing a protocol prefix allocated to the terminal device to the first network node.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: transmitting to the first network node one or more protocol configuration parameters for the terminal device. Optionally, the one or more protocol configuration parameters may be provisioned by at least one of the second network node and a server which allocates the protocol prefix to the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: obtaining protocol interface information for the terminal device from the first network node.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: receiving a request for prefix renewal information of the terminal device from the first network node; and transmitting the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: receiving a request for prefix delegation information of the terminal device from the first network node; and transmitting the prefix delegation information to the first network node to indicate a delegating prefix for the terminal device.

In accordance with an exemplary embodiment, the method according to the fifth aspect of the present disclosure may further comprise: transmitting a deactivation instruction to the first network node, in response to release of a connection (such as a PDN connection) associated with the protocol prefix allocated to the terminal device. The deactivation instruction indicates the first network node to disable the enabled capability of the protocol prefix management for the terminal device.

According to a sixth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the fifth aspect of the present disclosure.

According to a seventh aspect of the present disclosure, there is provided a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the method according to the fifth aspect of the present disclosure.

According to an eighth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise a receiving unit and optionally a determining unit. In accordance with some exemplary embodiments, the receiving unit may be operable to carry out at least the receiving step of the method according to the fifth aspect of the present disclosure. The determining unit may be operable to carry out at least the determining step of the method according to the fifth aspect of the present disclosure.

According to a ninth aspect of the present disclosure, there is provided a method performed by a terminal device such as UE. The method comprises transmitting a request for prefix allocation information of the terminal device to a first network node. The first network node may be indicated by a second network node to enable a capability of protocol prefix management for the terminal device. The method further comprises receiving the prefix allocation information from the first network node. The prefix allocation information comprises a protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the prefix allocation information may further comprise one or more protocol configuration parameters for the terminal device provisioned by at least one of: the first network node; the second network node; and a server which allocates the protocol prefix to the terminal device.

In accordance with an exemplary embodiment, the method according to the ninth aspect of the present disclosure may further comprise: sending a request for prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the method according to the ninth aspect of the present disclosure may further comprise: receiving prefix renewal information from the first network node to renew the protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the prefix renewal information may be provisioned by at least one of: the first network node; the second network node; and a server which allocates the protocol prefix to the terminal device.

In accordance with an exemplary embodiment, the method according to the ninth aspect of the present disclosure may further comprise: transmitting a request for prefix delegation information of the terminal device to the first network node; and receiving the prefix delegation information from the first network node. The prefix delegation information may comprise a delegating prefix for the terminal device. Optionally, the delegating prefix for the terminal device may be allocated by the second network node or a server which is able to allocate the delegating prefix to the terminal device.

According to a tenth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the ninth aspect of the present disclosure.

According to an eleventh aspect of the present disclosure, there is provided a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the method according to the ninth aspect of the present disclosure.

According to a twelfth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise a transmitting unit and a receiving unit. In accordance with some exemplary embodiments, the transmitting unit may be operable to carry out at least the transmitting step of the method according to the ninth aspect of the present disclosure. The receiving unit may be operable to carry out at least the receiving step of the method according to the ninth aspect of the present disclosure.

According to a thirteenth aspect of the present disclosure, there is provided a method performed by a server. The method comprises receiving a request for a protocol prefix for a terminal device from a first network node. The first network node is indicated by a second network node to enable a capability (e.g., a proxy function) of protocol prefix management for the terminal device. The method further comprises transmitting the protocol prefix allocated to the terminal device by the server to the first network node.

In accordance with an exemplary embodiment, the method according to the thirteenth aspect of the present disclosure may further comprise: receiving a request for one or more protocol configuration parameters for the terminal device from the first network node; and transmitting the one or more protocol configuration parameters for the terminal device to the first network node.

In accordance with an exemplary embodiment, the method according to the thirteenth aspect of the present disclosure may further comprise: receiving a request for prefix renewal information of the terminal device from the first network node; and transmitting the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device.

In accordance with an exemplary embodiment, the method according to the thirteenth aspect of the present disclosure may further comprise: receiving a request for prefix delegation information of the terminal device from the first network node; and transmitting the prefix delegation information to the first network node. The prefix delegation information may comprise a delegating prefix for the terminal device.

According to a fourteenth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise one or more processors and one or more memories comprising computer program codes. The one or more memories and the computer program codes may be configured to, with the one or more processors, cause the apparatus at least to perform any step of the method according to the thirteenth aspect of the present disclosure.

According to a fifteenth aspect of the present disclosure, there is provided a computer-readable medium having computer program codes embodied thereon which, when executed on a computer, cause the computer to perform any step of the method according to the thirteenth aspect of the present disclosure.

According to a sixteenth aspect of the present disclosure, there is provided an apparatus. The apparatus may comprise a receiving unit and a transmitting unit. In accordance with some exemplary embodiments, the receiving unit may be operable to carry out at least the receiving step of the method according to the thirteenth aspect of the present disclosure. The transmitting unit may be operable to carry out at least the transmitting step of the method according to the thirteenth aspect of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure itself, the preferable mode of use and further objectives are best understood by reference to the following detailed description of the embodiments when read in conjunction with the accompanying drawings, in which:

Figs. 1A-1B are diagrams illustrating two examples of Sx-u tunnel for IPv6 prefix management according to some embodiments of the present disclosure;

Fig. 2 is a diagram illustrating another example of Sx-u tunnel for IPv6 prefix management according to some embodiments of the present disclosure;

Figs. 3A-3B are diagrams illustrating an exemplary PGW-U acting as an IPv6 prefix management server according to some embodiments of the present disclosure;

Fig. 4 is a diagram illustrating an exemplary PGW-U acting as an IPv6 prefix management proxy according to some embodiments of the present disclosure;

Fig. 5A is a diagram illustrating an exemplary procedure of IPv6 prefix allocation and renewal according to some embodiments of the present disclosure;

Fig. 5B is a diagram illustrating an exemplary procedure of IPv6 prefix delegation according to some embodiments of the present disclosure;

Fig. 6A is a diagram illustrating another exemplary procedure of IPv6 prefix allocation and renewal according to some embodiments of the present disclosure;

Fig. 6B is a diagram illustrating another exemplary procedure of IPv6 prefix delegation according to some embodiments of the present disclosure;

Fig. 7 is a flowchart illustrating a method according to some embodiments of the present disclosure;

Fig. 8 is a flowchart illustrating another method according to some embodiments of the present disclosure;

Fig. 9 is a flowchart illustrating yet another method according to some embodiments of the present disclosure;

Fig. 10 is a flowchart illustrating a further method according to some embodiments of the present disclosure;

Fig. 11 is a block diagram illustrating an apparatus according to some embodiments of the present disclosure;

Fig. 12 is a block diagram illustrating another apparatus according to some embodiments of the present disclosure;

Fig. 13 is a block diagram illustrating another apparatus according to some embodiments of the present disclosure;

Fig. 14 is a block diagram illustrating yet another apparatus according to some embodiments of the present disclosure; and

Fig. 15 is a block diagram illustrating a further apparatus according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments of the present disclosure are described in detail with reference to the accompanying drawings. It should be understood that these embodiments are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the present disclosure, rather than suggesting any limitations on the scope of the present disclosure. Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present disclosure should be or are in any single embodiment of the disclosure. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present disclosure. Furthermore, the described features, advantages, and characteristics of the disclosure may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the disclosure may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the disclosure.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as new radio (NR) , long term evolution (LTE) , LTE-Advanced, wideband code division multiple access (WCDMA) , high-speed packet access (HSPA) , and so on. Furthermore, the communications between a terminal device and a network node in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , 4G, 4.5G, 5G communication protocols, and/or any other protocols either currently known or to be developed in the future.

As used herein, the terms “first” , “second” and so forth refer to different elements. The singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” as used herein, specify the presence of stated features, elements, and/or components and the like, but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof. The term “based on” is to be read as “based at least in part on” . The term “one embodiment” and “an embodiment” are to be read as “at least one embodiment” . The term “another embodiment” is to be read as “at least one other embodiment” . Other definitions, explicit and implicit, may be included below.

Wireless communication networks are widely deployed to provide various telecommunication services such as voice, video, data, messaging and broadcasts. To meet dramatically increasing network requirements on traffic capacity and data rates, one interesting option for communication technique development is to allow a separation of CP and UP functions for supporting diverse deployment scenarios (e.g. central or distributed UP functions) without affecting the overall functionality provided by the EPC entities such as SGW, PGW and TDF. For example, the CP and the UP of the PGW may be separated from each other into a PGW-C and a PGW-U. When a wireless device needs an IP address (such as IPv6 prefix) for communication with another device in the networks, at least one Sx-u tunnel may be required to transfer IPv6 prefix management massages between PGW-C and the wireless device.

Figs. 1A-1B are diagrams illustrating two examples of Sx-u tunnel for IPv6 prefix management according to some embodiments of the present disclosure. For simplicity, Figs. 1A-1B only depict some exemplary elements such as a UE 101, a PGW-U 102 and a PGW-C 103. The PGW-C 103 in Fig. 1B is directly connected with an external server (e.g., a DHCPv6/Radius/Diameter server) 104. In practice, a wireless communication system may further include any additional elements suitable to support communication between wireless devices or between a wireless device and another communication device, such as a landline telephone, a service provider, or any other network node or terminal device. By way of example and not limitation, the terminal device may refer to a mobile terminal, a UE, or other suitable devices. The wireless communication system may provide communication and various types of services to one or more wireless devices to facilitate the wireless devices’ access to and/or use of the services provided by, or via, the wireless communication system.

The two examples may be applicable to Scenario 1 where the UE IPv6 prefix is allocated by a PGW-C locally configured IP pool (as shown in Fig. 1A) , or allocated by an external DHCPv6/Radius/Diameter Server directly connected with the PGW-C (as shown in Fig. 1B) . In Scenario 1, an Sx-u tunnel between the PGW-C 103 and the PGW-U 102 needs to be introduced for the IPv6 RS/RA and/or DHCPv6 related configuration messages transferring between the UE 101 and the PGW-C 103. The tunnel handling in the PGW-C 103 and the PGW-U 102 is complicated as such Sx-u tunnel is needed for each PDN connection.

For IPv6 default prefix management via IPv6 stateless address auto-configuration, the PGW-C 103 configures the PGW-U 102 to forward router solicitation and neighbor solicitation messages from the UE 101 to the PGW-C 103. On the other hand, the PGW-C 103 forwards router advertisement and neighbor advertisement messages to the PGW-U 102 for relaying them to the UE 101.

For IPv6 parameter configuration via stateless DHCPv6, the PGW-C 103 configures the PGW-U 102 to forward all the DHCPv6 messages from the UE 101 to the PGW-C 103. On the other hand, the PGW-C 103 forwards the DHCPv6 response messages to the PGW-U 102 for relaying them to the UE 101.

For IPv6 prefix management via IPv6 prefix delegation, the PGW-C 103 configures the PGW-U 102 to forward all the DHCPv6 messages from the UE 101 to the PGW-C 103. Correspondingly, the PGW-C 103 forwards the DHCPv6 response messages to the PGW-U 102 for relaying them to the UE 101.

Fig. 2 is a diagram illustrating another example of Sx-u tunnel for IPv6 prefix management according to some embodiments of the present disclosure. For simplicity, Fig. 2 only depicts some exemplary elements such as a UE 201, a PGW-U1 202, a PGW-C 203, a PGW-U2 204 and an external server (e.g., a DHCPv6 server) 205. The example shown in Fig. 2 may be applicable to Scenario 2 where one or more external DHCPv6 servers are used for IPv6 prefix management, and the UE IPv6 prefix is allocated by the external DHCPv6 server which is reachable only via a PGW-U (such as the PGW-U2 204) .

For Scenario 2, in addition to the Sx-u tunnel between the PGW-C 203 and the PGW-U1 202 as described in Scenario 1, another standalone Sx-u tunnel is created to transfer IPv6 prefix management massages between the PGW-C 203 and the external server 205. This type of tunnel is required per external PDN or per external server. It can be seen from Fig. 2 that two Sx-u tunnels between CP and UP are required in Scenario 2, which makes the tunnel handling in the PGW-C 203, the PGW-U1 202 and the PGW-U2 204 more complicated as too many Sx-u tunnels need to be maintained.

Besides the tunnel handling in the PGW-C 203 and the PGW-U1 202 for the IPv6 RS/RA and/or DHCPv6 related configuration messages transferring between the UE 201 and the PGW-C 203, as described in connection with Figs. 1A-1B, the PGW-C 203 may be required to support more functionality in the case that an IP address of the UE 201 is obtained from an external PDN. In an embodiment where the IP address of the UE 201 is allocated by the DHCPv4/v6 server 205 in an external PDN and the DHCPv4/v6 server 205 is reachable only via the PGW-U2 204, as shown in Fig. 2, the PGW-C 203 needs to configure the PGW-U2 204 to forward all the DHCPv4/v6 messages from the DHCPv4/v6 server 205 in the external PDN to the PGW-C 203. On the other hand, the PGW-C 203 needs to forward the DHCPv4/v6 messages to the PGW-U2 204 for relaying them to the DHCPv4/v6 server 205 in the external PDN.

There may be some problems in Scenario 1 as shown in Figs. 1A-1B and Scenarios 2 as shown in Fig. 2 for the 4G CUPS and/or 5G core. For example, the handling of Sx-u tunnels complicates the product implementation and increases the deployment cost. Moreover, the transmission of IPv6 prefix management messages is not efficient compared to the approaches used before CUPS, and trouble shooting becomes difficult because extra one or even two hops are introduced on the message path. On the other hand, the network complexity is increased and the redundant Sx-u tunnel for the dedicated standalone Sx-u tunnel may need to be considered for high availability.

In order to enhance the transmission efficiency and improve the network performance, the present disclosure according to some exemplary embodiments proposes to simplify the IPv6 prefix management (e.g., IPv6 prefix allocation, renewal and delegation) , so that additional Sx-u tunnels used to transfer IPv6 management messages may not be needed in the 4G CUPS and 5G core. According to the proposed solution, a PGW-U may inform, for example, during the packet forwarding control protocol (PFCP) association setup procedure, a PGW-C of that the PGW-U supports the IPv6 prefix or address management server/proxy function. During PDN connection establishment, the PGW-C can decide, based at least in part on the policy used or to be used for IP prefix allocation, whether to enable the IPv6 prefix management function and which function needs to be enabled in the PGW-U. In the case that the corresponding IPv6 prefix management server or proxy function is enabled, the PGW-U can handle IPv6 prefix management messages for a UE.

Figs. 3A-3B are diagrams illustrating an exemplary PGW-U acting as an IPv6 prefix management server according to some embodiments of the present disclosure. For simplicity, Figs. 3A-3B only depict some exemplary elements such as a UE 301, a PGW-U 302 and a PGW-C 303. The PGW-C 303 in Fig. 3B is directly connected with an external server (e.g., a DHCPv6/Radius/Diameter server) 304. Corresponding to Figs. 1A-1B, the exemplary embodiments as illustrated in Figs. 3A-3B may be applicable to Scenario 1 where the UE IPv6 prefix may be allocated by a PGW-C locally configured IP pool (as shown in Fig. 3A) , or allocated by an external DHCPv6/Radius/Diameter server directly connected with the PGW-C (as shown in Fig. 3B) .

In accordance with an exemplary embodiment where the PGW-C 303 enables the “IPv6 prefix management server” function of the PGW-U 302 in Scenario 1, the PGW-U 302 can work as an IPv6 prefix management server to exchange IPv6 prefix management messages with the UE 301. In this case, the PGW-C 303 can allocate or obtain an IPv6 prefix for the UE 301 and send the IPv6 prefix to the PGW-U 302. The PGW-C 303 may optionally send some IPv6 configuration parameters to the PGW-U 302. In the case that the IPv6 prefix is allocated by a local pool at the PGW-C 303, the IPv6 configuration parameters can be locally configured at the PGW-U 302.

Optionally, the PGW-U 302 taking the IPv6 prefix management server role can directly send a message such as router advertisement with a new life time decided by the PGW-U 302 or the external server 304 to the UE 301 for prefix renewal. Alternatively or additionally, the PGW-U 302 also can take the “delegating router” role to directly handle DHCPv6 messages for IPv6 prefix delegation.

Fig. 4 is a diagram illustrating an exemplary PGW-U acting as an IPv6 prefix management proxy according to some embodiments of the present disclosure. For simplicity, Fig. 4 only depicts some exemplary elements such as a UE 401, a PGW-U 402, a PGW-C 403 and an external server (e.g., a DHCPv6 server) 404. Corresponding to Fig. 2, the exemplary embodiment as illustrated in Fig. 4 may be applicable to Scenario 2 where one or more external DHCPv6 servers are used for IPv6 prefix management, and the UE IPv6 prefix is allocated by the external DHCPv6 server which is reachable only via a PGW-U (such as the PGW-U 402) .

In accordance with an exemplary embodiment where the PGW-C 403 enables the “IPv6 prefix management proxy” function of the PGW-U 402 in Scenario 2, the PGW-U 402 can work as an IPv6 prefix management proxy to transfer IPv6 prefix management messages between the UE 401 and the external DHCPv6 server 404. In this case, the PGW-C 403 can send an indicator of a network instance (e.g., for an APN or a DN) , and optionally an address of the external DHCPv6 server 404 to the PGW-U 402. The PGW-U 402 can obtain an IPv6 prefix for the UE 401 from the external DHCPv6 server 404 and send the IPv6 prefix back to the PGW-C 403. Optionally, the PGW-U 402 may obtain IPv6 configuration parameters from the external DHCPv6 server 404. As such, the PGW-U 402 can handle the router solicitation and neighbor solicitation messages from the UE 401, and directly reply router advertisement and neighbor advertisement messages to the UE 401.

According to the exemplary embodiment, the PGW-U 402 taking the IPv6 prefix management proxy role can directly get some parameters for IPv6 prefix renewal from the external DHCPv6 server 404 and send these parameters in a router advertisement message to the UE 401. Alternatively o additionally, the PGW-U 402 can transfer DHCPv6 messages related to IPv6 prefix delegation between the UE 401 and the external DHCPv6 server 404.

It can be appreciated that although some exemplary embodiments are described with respect to the deployment case where the IPv6 prefix for a PDN connection and the IPv6 delegating prefix are allocated through the same approach: either from the PGW-C local IP pool, or from the same external server, the proposed solution is also applicable for other possible deployment cases.

It is noted that some embodiments of the present disclosure are mainly described in relation to LTE or NR specifications being used as non-limiting examples for certain exemplary network configurations and system deployments. As such, the description of exemplary embodiments given herein specifically refers to terminology which is directly related thereto. Such terminology is only used in the context of the presented non-limiting examples and embodiments, and does naturally not limit the present disclosure in any way. Rather, any other system configuration or radio technologies may equally be utilized as long as exemplary embodiments described herein are applicable.

Fig. 5A is a diagram illustrating an exemplary procedure of IPv6 prefix allocation and renewal according to some embodiments of the present disclosure. In accordance with some exemplary embodiments, an IPv6 prefix of a UE may be allocated by an IP pool locally configured at a PGW-C, or allocated by an external server such as a DHCPv6/Radius/Diameter server which is directly connected with the PGW-C. For simplicity, Fig. 5A only depicts some exemplary network elements such as a UE 501, a PGW-U 502, a PGW-C 503 and a server 504. It will be appreciated that signaling messages and network elements shown in Fig. 5A are just as examples, and more or less alternative signaling messages and network elements may be involved in the IPv6 prefix allocation and renewal procedure according to the embodiments of the present disclosure.

According to the procedure as illustrated in Fig. 5A, during a PFCP association setup procedure 511, the PGW-U 502 can inform the PGW-C 503 of a capability of the PGW-U 502 supporting at least an IPv6 prefix management server function (e.g., a server function, or server and proxy functions) . Optionally, the PGW-C 503 may receive 512 a create session request from a network entity such as mobility management entity/serving general packet radio service support node (MME/SGSN) , due to that the UE 501 initiates a PDN connection setup procedure, for example, by sending an attach request. By utilizing the information about the PGW-U 502 supporting at least an IPv6 prefix management server function, the PGW-C 503 can decide how to handle the IPv6 prefix allocation, renewal and/or delegation for the UE 501. For example, in the case that IPv6 prefix allocation is needed during PDN connection setup, the PGW-C 503 can activate a proper function for IPv6 prefix management of the PGW-U 502 based at least in part on the capability of the PGW-U and some information about the applicable prefix allocation approach (e.g., from a local pool or external servers) , if the PGW-U 502 is involved in message forwarding between the PGW-C 503 and an external server when the external server is used for IP address allocation, etc.

In response to the create session request, the PGW-C 503 may allocate an IPv6 prefix for the UE 501 from the locally configured IP pool. Optionally, the PGW-C 503 may get 513 the IPv6 prefix for the UE 501 from the server 504 (e.g., a DHCPv6/Radius/Diameter server directly connected with the PGW-C 503) . The PGW-C 503 can send 514 a PFCP session establishment request message to the PGW-U 502. According to the exemplary embodiment, the PFCP session establishment request message may include the allocated IPv6 prefix for the UE 501, and a new information element (IE) for enabling the IPv6 prefix management server function of the PGW-U 502. Correspondingly, the PGW-U 502 may take a role of IPv6 prefix management server.

The PGW-U 502 can send 515 a PFCP session establishment response message to the PGW-C 503. Optionally, the PFCP session establishment response message may include an identifier of an IPv6 interface allocated by the PGW-U 502, which is denoted as IPv6 interface ID-PGW-U in Fig. 5A. The PGW-C 503 may send 516 a create session response to a SGW-C/MME with the IPv6 interface ID-PGW-U. Then the SGW-C/MME can forward the create session response to the UE 501 by a NAS message.

The UE 501 may send 517 a router solicit message to the PGW-U 502 which takes the role of the IPv6 prefix management server and handles the incoming router solicit for IPv6. According to the exemplary embodiment, the PGW-U 502 can send 518 a router advertisement message to the UE 501 with the IPv6 prefix allocated for a PDN connection of the UE 501 and the related configuration parameters. The configuration parameters may be locally configured in the PGW-U 502 or obtained from the PGW-C 503 during PFCP session establishment.

In accordance with some exemplary embodiments, an IPv6 prefix renewal procedure may be initiated for the UE 501. In order to renew the allocated IPv6 prefix, the PGW-U 502 can send 519 a router advertisement message to the UE 501 with the same IPv6 prefix as that previously allocated for the PDN connection of the UE 501 and a new life time corresponding to the IPv6 prefix. The PGW-U 502 may handle the IPv6 prefix renewal by configuring the new life time corresponding to the IPv6 prefix. Alternatively, the PGW-U 502 may request the new life time from another network node such as the PGW-C 503 or the server 504. For example, the PGW-U 502 may send 519a a message such as a PFCP IP address management request for IPv6 prefix renewal to the PGW-C 503. The PGW-C 503 may configure the new life time locally and send 519c the new life time to the PGW-U 502 in a PFCP IP address management response. Optionally, the new life time may be obtained 519b from the server 504 by the PGW-C 503 to renew the IPv6 prefix of the UE 501.

Fig. 5B is a diagram illustrating an exemplary procedure of IPv6 prefix delegation according to some embodiments of the present disclosure. The IPv6 prefix delegation as illustrated in Fig. 5B may happen after the IPv6 prefix renewal as illustrated in Fig. 5A. However, it can be appreciated that the IPv6 prefix delegation in practice may happen before or after IPv6 prefix renewal. In order to initiate the procedure of IPv6 prefix delegation, the UE 501 may send 520 a solicit message to the PGW-U 502 to request an IPv6 delegating prefix. The PGW-U 502 can request the delegating prefix from the PGW-C 503 by sending 521 a PFCP IP prefix management request. The PGW-C 503 can get the IPv6 delegating prefix from a local IP pool or obtain 521a the IPv6 delegating prefix from the server 504. The IPv6 delegating prefix may be sent 522 to the PGW-U 502 in a PFCP prefix management response. Then the PGW-U 502 can send 523 the delegating prefix in a reply message to the UE 501. The reply message may indicate the IPv6 prefix allocated for the PDN connection of the UE 501 as the excluded prefix.

Fig. 6A is a diagram illustrating another exemplary procedure of IPv6 prefix allocation and renewal according to some embodiments of the present disclosure. For simplicity, Fig. 6A only depicts some exemplary network elements such as a UE 601, a PGW-U 602, a PGW-C 603 and a server 604. In the embodiment shown in Fig. 6A, the server 604 (such as an external DHCPv6 server) is used for IPv6 prefix management and reachable only via the PGW-U 602. In accordance with the exemplary embodiment, the PGW-U 602 acts as an IPv6 prefix management proxy to transfer IPv6 prefix management messages between the UE 601 and the server 604. It will be appreciated that signaling messages and network elements shown in Fig. 6A are just as examples, and more or less alternative signaling messages and network elements may be involved in the IPv6 prefix allocation and renewal procedure according to the embodiments of the present disclosure.

According to the procedure as illustrated in Fig. 6A, during a PFCP association setup procedure 611, the PGW-U 602 can inform the PGW-C 603 of that the PGW-U 602 can support at least an IPv6 prefix management proxy function, (e.g., a proxy function, or server and proxy functions) . Optionally, the PGW-C 603 may receive 612 a create session request from a network entity such as an MME/SGSN, due to that the UE 601 initiates a PDN connection setup procedure, for example, by sending an attach request. According to the information about the PGW-U 602 supporting at least an IPv6 prefix management proxy function, the PGW-C 603 can determine whether to enable the IPv6 prefix management proxy function of the PGW-U 602 to handle the IPv6 prefix allocation, renewal and/or delegation for the UE 601. For example, in the case that IPv6 prefix allocation is needed during PDN connection setup, the PGW-C 603 can activate a proper function for IPv6 prefix management of the PGW-U 602 based at least in part on the capability of the PGW-U and some information about the applicable prefix allocation approach (e.g., from a local pool or external servers) , if the PGW-U 602 is involved in message forwarding between the PGW-C 603 and an external server when the external server is used for IP address allocation, etc.

In response, the PGW-C 603 can send 613 a PFCP session establishment request message to the PGW-U 602. According to the exemplary embodiment, the PFCP session establishment request message may include a new IE for indicating the PGW-U 602 to enable the IPv6 prefix management proxy function. The PFCP session establishment request message may indicate a network instance (e.g., for an APN or DN) for the UE 601. Optionally, the PFCP session establishment request message may also include an identifier (such as a name, an address, a sequence number, etc. ) of the server 604, such as a DHCPv6 server address provided by the PGW-C 603. Alternatively, the PGW-U 602 can obtain the DHCPv6 server address according to local configurations.

After receiving the PFCP session establishment request message indicating enablement of the IPv6 prefix management proxy function, the PGW-U 602 can take a role of IPv6 prefix management proxy for DHCP. For example, the PGW-U 602 can send 614 a DHCP solicit message to the directly connected server 604, and the server 604 may send 615 a DHCP reply with an IPv6 prefix allocated for the UE 601 to the PGW-U 602. The PGW-U 602 can send 616 a PFCP session establishment response message with the IPv6 prefix to the PGW-C 603. The PFCP session establishment response message may include an identifier of an IPv6 interface allocated by the PGW-U 602, which is denoted as IPv6 interface ID-PGW-U in Fig. 6A. The PGW-C 603 may send 617 a create session response to a SGW-C/MME with the IPv6 interface ID-PGW-U. Then the SGW-C/MME can forward the create session response to the UE 601 by a NAS message.

The UE 601 may send 618 a router solicit message to the PGW-U 602 which takes the role of the IPv6 prefix management proxy and handles the incoming router solicit for IPv6. According to the exemplary embodiment, the PGW-U 602 can send 619 a DHCP request to the server 604 for configuration parameters. Correspondingly, the server 604 may send 620 a DHCP reply with configuration parameters to the PGW-U 602. Then, the PGW-U 602 can send 621 a router advertisement message with the IPv6 prefix allocate for a PDN connection of the UE 601 and the related configuration parameters to the UE 601.

In order to renew the IPv6 prefix for the UE 601, the PGW-U 602 which acts as a client can send 622 a DHCP renew message to the server 604. Then the server 604 may send 623 a new life time for renewing the IPv6 prefix to the PGW-U 602 in a DHCP reply message. Correspondingly, the PGW-U 602 can send 624 a router advertisement message to the UE 601 with the same IPv6 prefix and the new life time. Although Fig. 5A and Fig. 6A show the IPv6 prefix renewal procedure as being triggered by the network side (e.g., via the PGW-U) , it can be realized that the IPv6 prefix renewal procedure also may be initiated by the UE, for example, by means of sending a request for renewing the IPv6 prefix to the PGW-U. Optionally, the UE can trigger a PDN connection release procedure and exchange related signaling messages with the PGW-U.

Fig. 6B is a diagram illustrating another exemplary procedure of IPv6 prefix delegation according to some embodiments of the present disclosure. The IPv6 prefix delegation as illustrated in Fig. 6B may happen after the IPv6 prefix renewal as illustrated in Fig. 6A. Alternatively, the IPv6 prefix delegation also may happen before the IPv6 prefix renewal. In the procedure of IPv6 prefix delegation, the UE 601 may send 625 a DHCP solicit message to the PGW-U 602 to request an IPv6 delegating prefix. The PGW-U 602 can forward 626 the DHCP request to the server 604. In response, the server 604 allocates and sends 627 the IPv6 delegating prefix for the UE 601 to the PGW-U 602 in a DHCP reply message. The PGW-U 602 then sends 628 the IPv6 delegating prefix in a DHCP reply message to the UE 601. The DHCP reply message may indicate the IPv6 prefix allocated for the PDN connection of the UE 601 as the excluded prefix.

As described previously, the proposed solution according to one or more exemplary embodiments can simplify the IPv6 prefix management by enabling a PGW-U to function as an IPv6 prefix management server or proxy. For example, a PGW-C can be informed of a capability of a PGW-U supporting an IPv6 prefix management server function and/or an IPv6 prefix management proxy function, by a new PFCP IE or an indicator of this capability added in a PFCP association setup request/response message. The PGW-C can enable the IPv6 prefix management server or proxy function of the PGW-U by one or more new PFCP IEs added in a PFCP session establishment request/response message. Optionally, some new PFCP messages may be introduced for IPv6 prefix management of a UE.

Taking advantageous of the proposed solution can simplify the network structure, make trouble shooting easy and reduce the development cost. On the other hand, the transmission efficiency of IPv6 prefix management messages also can be improved with the fast protocol data unit (PDU) session setup and the optimized function allocation in a PGW-C and a PGW-U. It will be appreciated that although the exemplary embodiments described herein are mainly based on a PGW-C and a PGW-U, the proposed solution may be equally applicable for a session management function (SMF) and a user plane function (UPF) /anchor in 5G core, as well as other suitable network nodes in the communication networks.

Fig. 7 is a flowchart illustrating a method 700 according to some embodiments of the present disclosure. The method 700 illustrated in Fig. 7 may be performed by a first network node or an apparatus communicatively coupled to the first network node. In accordance with an exemplary embodiment, the first network node may comprise a PGW-U (such as the PGW-

U

302, 402, 502 or 602) , a UPF or any other suitable network function or instance which can act as a protocol prefix management (such as IPv6 prefix management) server/proxy.

According to the exemplary method 700 illustrated in Fig. 7, the first network node can determine capability information of the first network node, as shown in block 702. The capability information may indicate that the first network node can support a capability of protocol prefix management for a terminal device (such as the

UE

301, 401, 501 or 601) . In accordance with some exemplary embodiments, the capability of the protocol prefix management may comprise at least one of a server function and a proxy function for the protocol prefix management. As described in connection with Figs. 3A-6B, the protocol prefix management may comprise IPv6 prefix management.

In accordance with some exemplary embodiments, the first network node can transmit the capability information to a second network node, as shown in block 704. The second network node may comprise a PGW-C such as the PGW-

C

303, 403, 503 or 603. Based at least on the capability information, the second network node can determine whether to enable any function for the protocol prefix management of the first network node. Optionally, the first network node may receive an activation instruction from the second network node to indicate the first network node to enable the capability of the protocol prefix management for the terminal device, for example, the server function or the proxy function for the protocol prefix management.

In response to reception of the activation instruction indicating the first network node to enable the server function for the protocol prefix management, the first network node may enable a server function for the protocol prefix management. In this case, the first network node can obtain a protocol prefix allocated to the terminal device from the second network node. Optionally, the protocol prefix allocated to the terminal device may be provisioned by the second network node locally or by an external server (such as the server 504) connected with the second network node.

Alternatively, in response to reception of the activation instruction indicating the first network node to enable the proxy function for the protocol prefix management, the first network node may enable a proxy function for the protocol prefix management. Optionally, the first network node can obtain an indicator of a network instance for the terminal device from the second network node. In accordance with some exemplary embodiments, the first network node can send a request for a protocol prefix for the terminal device to a server which is able to allocate the protocol prefix to the terminal device, and then obtain the protocol prefix allocated to the terminal device from the server. According to some exemplary embodiments, the protocol prefix allocated to the terminal device can be transmitted by the first network node to the second network node. It will be appreciated that an identifier (such as an address, a name, a sequence number and etc. ) of the server may be acquired by the first network node according to local configurations or from the second network node.

In accordance with some exemplary embodiments, the first network node (which may act as an IPv6 prefix management server or proxy) can provide protocol interface information (such as IPv6 interface ID-PGW-U) for the terminal device to the second network node. The protocol interface information may be used in a session creation procedure for the terminal device.

In accordance with some exemplary embodiments, the first network node may receive a request for prefix allocation information from the terminal device. In response, the first network node may transmit the prefix allocation information to the terminal device. The prefix allocation information may comprise the protocol prefix allocated to the terminal device. According to an exemplary embodiment, the protocol prefix allocated to the terminal device may comprise a protocol prefix for a PDN connection. Optionally, the prefix allocation information may further comprise one or more protocol configuration parameters for the terminal device. The one or more protocol configuration parameters may be provisioned by at least one of the first network node, the second network node, and a server which allocates the protocol prefix to the terminal device.

In accordance with some exemplary embodiments, the one or more protocol configuration parameters (such as DHCPv6 configuration parameters) can be used by the terminal device to perform protocol prefix configuration. In the case that the first network node acts as a protocol prefix management server, the first network node can acquire the one or more protocol configuration parameters locally or from the second network node. Optionally, the second network node can fetch the one or more protocol configuration parameters from a protocol server which allocates the protocol prefix to the terminal device. In the case that the first network node acts as a protocol prefix management proxy, the first network node can get the one or more protocol configuration parameters directly from a protocol server which allocates the protocol prefix to the terminal device.

Optionally, a protocol prefix renewal procedure may be triggered by the terminal device itself or by the first network node. In accordance with some exemplary embodiments, the first network node can renew the protocol prefix allocated to the terminal device by sending prefix renewal information to the terminal device. The prefix renewal information (e.g., including a new life time for the protocol prefix allocated to the terminal device) may be provisioned by at least one of the first network node, the second network node, and a server which allocates the protocol prefix to the terminal device. For example, in the case that the first network node acts as a protocol prefix management server, the first network node can acquire the prefix renewal information locally or from the second network node. Optionally, the second network node can fetch the prefix renewal information from a protocol server which allocates the protocol prefix to the terminal device. In the case that the first network node acts as a protocol prefix management proxy, the first network node can get the prefix renewal information directly from a protocol server which allocates the protocol prefix to the terminal device.

In accordance with some exemplary embodiments, the first network node may receive a request for prefix delegation information from the terminal device. In response, the first network node can transmit the prefix delegation information to the terminal device. The prefix delegation information may comprise a delegating prefix for the terminal device. Optionally, the prefix delegation information may indicate the protocol prefix for the PDN connection as an excluded prefix. According to some exemplary embodiments, the delegating prefix for the terminal device may be obtained by the first network node from the second network node (e.g., in the case that the first network node enables the server function for protocol prefix management) , or a server which is able to allocate the delegating prefix to the terminal device (e.g., in the case that the first network node enables the proxy function for protocol prefix management) .

Fig. 8 is a flowchart illustrating a method 800 according to some embodiments of the present disclosure. The method 800 illustrated in Fig. 8 may be performed by a second network node or an apparatus communicatively coupled to the second network node. In accordance with an exemplary embodiment, the second network node may comprise a PGW-C (such as the PGW-

C

303, 403, 503 or 603) , a SMF or any other suitable network function or instance which can indicate the first network node as described in connection with Fig. 7 to act as a protocol prefix management (such as IPv6 prefix management) server/proxy.

According to the exemplary method 800 illustrated in Fig. 8, the second network node may receive capability information from a first network node (such as the PGW-

U

302, 402, 502 or 602) , as shown in block 802. The capability information can inform the second network node of that the first network node supports a capability of protocol prefix management for a terminal device (such as the

UE

301, 401, 501 or 601) . The capability of the protocol prefix management (e.g., IPv6 prefix management) may comprise at least one of a server function and a proxy function for the protocol prefix management, as described in connection with Fig. 7.

Optionally, based at least in part on the capability information, the second network node can determine whether to enable the capability of the protocol prefix management of the first network node, as shown in block 804. Specifically, the second network node can determine whether to enable the server function or the proxy function for the protocol prefix management of the first network node. For example, during PDN connection setup, a PGW-C may activate, based at least in part on the capability of a PGW-U, the available prefix allocation approach (e.g., by means of a local pool or an external server) , whether the PGW-U is involved in message forwarding between the PGW-C and an external server when the external server is used for IPv6 prefix allocation, etc.

In response to determination of enabling the proxy function of the first network node for the terminal device, the second network node may transmit an activation instruction to the first network node, so as to indicate the first network node to enable a proxy function for the protocol prefix management. In accordance with some exemplary embodiments, the second network node may indicate a network instance (e.g., for an APN or a DN) for the terminal device to the first network node. Optionally, the second network node may inform the first network node of an identifier of a server (such as the server 604) which is able to allocate a protocol prefix to the terminal device.

As described in connection with Fig. 7, the first network node which acts as a protocol prefix management proxy can get a protocol prefix for the terminal device from the server which is reachable with the first network node. Correspondingly, the second network node can receive the protocol prefix allocated to the terminal device from the first network node.

Alternatively, in response to determination of enabling the server function of the first network node for the terminal device, the second network node may transmit an activation instruction to the first network node, so as to indicate the first network node to enable a server function for the protocol prefix management. In this case, the second network node can provide the first network node with a protocol prefix allocated to the terminal device (e.g., by the second network node or a protocol server connected with the second network node) . Optionally, the second network node may transmit one or more protocol configuration parameters for the terminal device to the first network node, so that the first network node can forward the one or more protocol configuration parameters to the terminal device. The one or more protocol configuration parameters related to the protocol prefix allocated to the terminal device may be provisioned by at least one of the second network node and a server which allocates the protocol prefix to the terminal device.

In accordance with some exemplary embodiments, the second network node can obtain protocol interface information (such as IPv6 interface ID-PGW-U) for the terminal device from the first network node, so as to create a session for the terminal device by using the protocol interface information.

According to an exemplary embodiment where the server function for the protocol prefix management of the first network node is enabled, the second network node may receive a request for prefix renewal information of the terminal device from the first network node. In response, the second network node can transmit the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device, for example, by including a new life time in the prefix renewal information. The protocol prefix allocated to the terminal device may comprise a protocol prefix for a PDN connection.

Optionally, the second network node may receive a request for prefix delegation information of the terminal device from the first network node which enables the server function for the protocol prefix management. In response, the second network node can transmit the prefix delegation information to the first network node to indicate a delegating prefix for the terminal device. According to an exemplary embodiment, the second network node may obtain the delegating prefix for the terminal device from a server which is able to allocate this delegating prefix.

Fig. 9 is a flowchart illustrating a method 900 according to some embodiments of the present disclosure. The method 900 illustrated in Fig. 4 may be performed by a terminal device or an apparatus communicatively coupled to the terminal device. In accordance with an exemplary embodiment, the terminal device may refer to any end device that can access a communication network and receive services therefrom. By way of example and not limitation, the terminal device may refer to a mobile terminal, a UE, or other suitable devices. The UE may be, for example, a subscriber station, a portable subscriber station, a mobile station (MS) or an access terminal (AT) . The terminal device may include, but not limited to, portable computers, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, a mobile phone, a cellular phone, a smart phone, a tablet, a wearable device, a personal digital assistant (PDA) , a vehicle, and the like.

As yet another specific example, in an Internet of things (IoT) scenario, a terminal device may also be called an IoT device and represent a machine or other device that performs monitoring, sensing and/or measurements etc., and transmits the results of such monitoring, sensing and/or measurements etc. to another terminal device and/or a network equipment. The terminal device may in this case be a machine-to-machine (M2M) device, which may in a 3rd generation partnership project (3GPP) context be referred to as a machine-type communication (MTC) device.

As one particular example, the terminal device may be a UE implementing the 3GPP narrow band Internet of things (NB-IoT) standard. Particular examples of such machines or devices are sensors, metering devices such as power meters, industrial machinery, or home or personal appliances, e.g. refrigerators, televisions, personal wearables such as watches etc. In other scenarios, a terminal device may represent a vehicle or other equipment, for example, a medical instrument that is capable of monitoring, sensing and/or reporting etc. on its operational status or other functions associated with its operation.

According to the exemplary method 900 illustrated in Fig. 9, the terminal device can transmit a request for prefix allocation information of the terminal device to a first network node, as shown in block 902. In accordance with some exemplary embodiments, the first network node (such as the PGW-

U

302, 402, 502 or 602) may be indicated by a second network node (such as the PGW-

C

303, 403, 503 or 603) to enable a capability of protocol prefix management for the terminal device, for example, a server or proxy function for the protocol prefix management (such as IPv6 prefix management) .

In accordance with some exemplary embodiments, the terminal device may receive the prefix allocation information from the first network node, as shown in block 904. The terminal device can get a protocol prefix (such as an IPv6 prefix for a PDN connection) in the prefix allocation information. Optionally, the prefix allocation information may further comprise one or more protocol configuration parameters for the terminal device provisioned by the first network node, the second network node and/or a server which allocates the protocol prefix to the terminal device.

In accordance with some exemplary embodiments, the terminal device may receive prefix renewal information from the first network node to renew the protocol prefix allocated to the terminal device. It can be realized that the renewal of the protocol prefix allocated to the terminal device may be triggered by the terminal device or by the first network node, so that the terminal device can get a new life time for the allocated protocol prefix. Optionally, the prefix renewal information may be provisioned by at least one of the first network node, the second network node and a server which allocates the protocol prefix to the terminal device.

Alternatively or additionally, the terminal device may transmit a request for prefix delegation information of the terminal device to the first network node, and receive the prefix delegation information from the first network node. The prefix delegation information may comprise a delegating prefix for the terminal device. For example, the delegating prefix may be allocated by the second network node or a server which is able to allocate the delegating prefix to the terminal device. Optionally, the prefix delegation information may indicate the protocol prefix for the PDN connection as an excluded prefix.

In accordance with some exemplary embodiments, the terminal device may initiate or trigger a PDN connection release procedure related to the protocol prefix allocated to the terminal device. During the PDN connection release procedure, the terminal device can exchange some protocol prefix release messages and/or related information with the first network node, so as to release the protocol prefix allocated to the terminal device.

Fig. 10 is a flowchart illustrating a method 1000 according to some embodiments of the present disclosure. The method 1000 illustrated in Fig. 10 may be performed by a server or an apparatus communicatively coupled to the server. In accordance with an exemplary embodiment, the server may comprise a DHCPv6/Radius/Diameter server, or any other suitable server which is able to allocate a protocol prefix (such as IPv6 prefix) to a terminal device. Optionally, the server such as the

server

504 or 604 may exchange protocol prefix management messages for a UE with a PGW-C and/or a PGW-U.

According to the exemplary method 1000 illustrated in Fig. 10, the server may receive a request for a protocol prefix for a terminal device from a first network node, as shown in block 1002. In response, the server can transmit the protocol prefix allocated to the terminal device by the server to the first network node, as shown in block 1004. As described in connection with Figs. 7-9, the first network node (such as the PGW-

U

C

303, 403, 503 or 603) to enable a capability of protocol prefix management (such as IPv6 prefix management) for the terminal device. It will be appreciated that in the case of a server function for the protocol prefix management of the first network node being activated, the server may not exchange information with the first network node directly, as illustrated in Figs. 5A-5B. Optionally, the server can provide some protocol prefix management related information to the first network node through the second network node.

In accordance with an exemplary embodiment where a proxy function for the protocol prefix management of the first network node is enabled, the server may receive a request for one or more protocol configuration parameters for the terminal device from the first network node, and transmit the one or more protocol configuration parameters to the first network node. The one or more protocol configuration parameters may be associated with the protocol prefix allocated to the terminal device, such as a protocol prefix for a PDN connection.

Optionally, the server may receive a request for prefix renewal information of the terminal device from the first network node. In response, the server can transmit the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device. The prefix renewal information may indicate a new life time for the protocol prefix allocated to the terminal device.

Alternatively or additionally, the server may receive a request for prefix delegation information of the terminal device from the first network node. In response, the server can transmit the prefix delegation information to the first network node to indicate a delegating prefix for the terminal device.

The proposed solution according to one or more exemplary embodiments can enable a first network node such as PGW-U (e.g., in response to an instruction by a second network node such as a PGW-C) to function as a protocol prefix management server or proxy for a UE. In an exemplary embodiment where an IPv6 prefix for a UE may be allocated by a PGW-C locally configured IP pool or allocated by an external DHCPv6/Radius/Diameter server which is directly connected with the PGW-C, the PGW-U can work as an IPv6 prefix management server to manage the IPv6 prefix and parameters configuration. Alternatively, in an exemplary embodiment where an external DHCPv6 server may be used for IPv6 prefix management and reachable only via a PGW-U, the PGW-U can act as an IPv6 prefix management proxy to handle and transfer UE IPv6 prefix management related messages. As such, it is not necessary to create one or more extra Sx-u tunnels for IPv6 management message transmissions in the 4G CUPS and 5G core.

The various blocks shown in Figs. 7-10 may be viewed as method steps, and/or as operations that result from operation of computer program code, and/or as a plurality of coupled logic circuit elements constructed to carry out the associated function (s) . The schematic flow chart diagrams described above are generally set forth as logical flow chart diagrams. As such, the depicted order and labeled steps are indicative of specific embodiments of the presented methods. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more steps, or portions thereof, of the illustrated methods. Additionally, the order in which a particular method occurs may or may not strictly adhere to the order of the corresponding steps shown.

Fig. 11 is a block diagram illustrating an apparatus 1100 according to various embodiments of the present disclosure. As shown in Fig. 11, the apparatus 1100 may comprise one or more processors such as processor 1101 and one or more memories such as memory 1102 storing computer program codes 1103. The memory 1102 may be non-transitory machine/processor/computer readable storage medium. In accordance with some exemplary embodiments, the apparatus 1100 may be implemented as an integrated circuit chip or module that can be plugged or installed into a first network node as described with respect to Fig. 7, a second network node as described with respect to Fig. 8, a terminal device as described with respect to Fig. 9, or a server as described with respect to Fig. 10.

In some implementations, the one or more memories 1102 and the computer program codes 1103 may be configured to, with the one or more processors 1101, cause the apparatus 1100 at least to perform any operation of the method as described in connection with Fig. 7. In some implementations, the one or more memories 1102 and the computer program codes 1103 may be configured to, with the one or more processors 1101, cause the apparatus 1100 at least to perform any operation of the method as described in connection with Fig. 8. In some implementations, the one or more memories 1102 and the computer program codes 1103 may be configured to, with the one or more processors 1101, cause the apparatus 1100 at least to perform any operation of the method as described in connection with Fig. 9. In other implementations, the one or more memories 1102 and the computer program codes 1103 may be configured to, with the one or more processors 1101, cause the apparatus 1100 at least to perform any operation of the method as described in connection with Fig. 10.

Alternatively or additionally, the one or more memories 1102 and the computer program codes 1103 may be configured to, with the one or more processors 1101, cause the apparatus 1100 at least to perform more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 12 is a block diagram illustrating an apparatus 1200 according to some embodiments of the present disclosure. The apparatus 1200 may be implemented as a first network node or as a part of the first network node. As shown in Fig. 12, the apparatus 1200 may comprise a determining unit 1201 and a transmitting unit 1202. In an exemplary embodiment, the apparatus 1200 may be implemented in a first network node such as a PGW-U or a UPF. The determining unit 1201 may be operable to carry out the operation in block 702, and the transmitting unit 1202 may be operable to carry out the operation in block 704. Optionally, the determining unit 1201 and/or transmitting unit 1202 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 13 is a block diagram illustrating an apparatus 1300 according to some embodiments of the present disclosure. The apparatus 1300 may be implemented as a second network node or as a part of the second network node. As shown in Fig. 13, the apparatus 1300 may comprise a receiving unit 1301 and optionally a determining unit 1302. In an exemplary embodiment, the apparatus 1300 may be implemented in a second network node such as a PGW-C or a SMF. The receiving unit 1301 may be operable to carry out the operation in block 802, and the determining unit 1302 may be operable to carry out the optional operation in block 804. Optionally, the receiving unit 1301 and/or determining unit 1302 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 14 is a block diagram illustrating an apparatus 1400 according to some embodiments of the present disclosure. The apparatus 1400 may be implemented as a terminal device or as a part of the terminal device. As shown in Fig. 14, the apparatus 1400 may comprise a transmitting unit 1401 and a receiving unit 1402. In an exemplary embodiment, the apparatus 1400 may be implemented in a terminal device such as UE. The transmitting unit 1401 may be operable to carry out the operation in block 902, and the receiving unit 1402 may be operable to carry out the operation in block 904. Optionally, the transmitting unit 1401 and/or receiving unit 1402 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

Fig. 15 is a block diagram illustrating an apparatus 1500 according to some embodiments of the present disclosure. The apparatus 1500 may be implemented as a server or as a part of the server. As shown in Fig. 1500, the apparatus 1500 may comprise a receiving unit 1501 and a transmitting unit 1502. In an exemplary embodiment, the apparatus 1500 may be implemented in a server such as a DHCPv6/Radius/Diameter server. The receiving unit 1501 may be operable to carry out the operation in block 1002, and the transmitting unit 1502 may be operable to carry out the operation in block 1004. Optionally, the receiving unit 1501 and/or the transmitting unit 1502 may be operable to carry out more or less operations to implement the proposed methods according to the exemplary embodiments of the present disclosure.

In general, the various exemplary embodiments may be implemented in hardware or special purpose chips, circuits, software, logic or any combination thereof. For example, some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device, although the disclosure is not limited thereto. While various aspects of the exemplary embodiments of this disclosure may be illustrated and described as block diagrams, flow charts, or using some other pictorial representation, it is well understood that these blocks, apparatus, systems, techniques or methods described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

As such, it should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be practiced in various components such as integrated circuit chips and modules. It should thus be appreciated that the exemplary embodiments of this disclosure may be realized in an apparatus that is embodied as an integrated circuit, where the integrated circuit may comprise circuitry (as well as possibly firmware) for embodying at least one or more of a data processor, a digital signal processor, baseband circuitry and radio frequency circuitry that are configurable so as to operate in accordance with the exemplary embodiments of this disclosure.

It should be appreciated that at least some aspects of the exemplary embodiments of the disclosure may be embodied in computer-executable instructions, such as in one or more program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types when executed by a processor in a computer or other device. The computer executable instructions may be stored on a computer readable medium such as a hard disk, optical disk, removable storage media, solid state memory, random access memory (RAM) , etc. As will be appreciated by one of skill in the art, the function of the program modules may be combined or distributed as desired in various embodiments. In addition, the function may be embodied in whole or partly in firmware or hardware equivalents such as integrated circuits, field programmable gate arrays (FPGA) , and the like.

The present disclosure includes any novel feature or combination of features disclosed herein either explicitly or any generalization thereof. Various modifications and adaptations to the foregoing exemplary embodiments of this disclosure may become apparent to those skilled in the relevant arts in view of the foregoing description, when read in conjunction with the accompanying drawings. However, any and all modifications will still fall within the scope of the non-limiting and exemplary embodiments of this disclosure.

Claims

A method performed by a first network node, comprising:

determining capability information of the first network node, wherein the capability information indicates that the first network node supports a capability of protocol prefix management for a terminal device; and

transmitting the capability information to a second network node.
The method according to claim 1, wherein the capability of the protocol prefix management comprises at least one of a server function and a proxy function for the protocol prefix management.
The method according to claim 1 or 2, further comprising:

receiving an activation instruction from the second network node, wherein the activation instruction indicates the first network node to enable the capability of the protocol prefix management for the terminal device.
The method according to claim 3, further comprising:

enabling a server function for the protocol prefix management of the first network node, in response to reception of the activation instruction indicating the first network node to enable the server function for the protocol prefix management.
The method according to claim 4, further comprising:

obtaining a protocol prefix allocated to the terminal device from the second network node.
The method according to claim 3, further comprising:

enabling a proxy function for the protocol prefix management of the first network node, in response to reception of the activation instruction indicating the first network node to enable the proxy function for the protocol prefix management.
The method according to claim 6, further comprising:

obtaining an indicator of a network instance for the terminal device from the second network node.
The method according to claim 6 or 7, further comprising:

sending a request for a protocol prefix for the terminal device to a server which is able to allocate the protocol prefix to the terminal device; and

obtaining the protocol prefix allocated to the terminal device from the server.
The method according to claim 8, further comprising:

transmitting the protocol prefix allocated to the terminal device to the second network node.
The method according to claim 5 or 9, further comprising:

providing protocol interface information for the terminal device to the second network node.
The method according to claim 5, 9 or 10, further comprising:

receiving a request for prefix allocation information from the terminal device; and

transmitting the prefix allocation information to the terminal device, wherein the prefix allocation information comprises the protocol prefix allocated to the terminal device.
The method according to claim 11, wherein the prefix allocation information further comprises one or more protocol configuration parameters for the terminal device provisioned by at least one of:

the first network node;

the second network node; and

a server which allocates the protocol prefix to the terminal device.
The method according to claim 11 or 12, further comprising:

renewing the protocol prefix allocated to the terminal device by sending prefix renewal information to the terminal device.
The method according to claim 13, wherein the prefix renewal information is provisioned by at least one of:

the first network node;

the second network node; and

a server which allocates the protocol prefix to the terminal device.
The method according to any of claims 11-14, wherein the protocol prefix allocated to the terminal device comprises a protocol prefix for a packet data network connection.
The method according to claim 15, further comprising:

receiving a request for prefix delegation information from the terminal device; and

transmitting the prefix delegation information to the terminal device, wherein the prefix delegation information comprises a delegating prefix for the terminal device.
The method according to claim 16, wherein the delegating prefix for the terminal device is obtained by the first network node from one of:

the second network node; and

a server which is able to allocate the delegating prefix to the terminal device.
The method according to claim 16 or 17, wherein the prefix delegation information indicates the protocol prefix for the packet data network connection as an excluded prefix.
The method according to any of claims 3-18, further comprising:

receiving a deactivation instruction from the second network node, wherein the deactivation instruction indicates the first network node to disable the enabled capability of the protocol prefix management for the terminal device; and

disabling the enabled capability of the protocol prefix management for the terminal device according to the deactivation instruction.
The method according to any of claims 1-19, wherein the protocol prefix management comprises internet protocol version 6 prefix management.
The method according to any of claims 1-20, wherein the first network node comprises a packet data network gateway user plane function and the second network node comprises a packet data network gateway control plane function.
A method performed by a second network node, comprising:

receiving capability information from a first network node, wherein the capability information indicates that the first network node supports a capability of protocol prefix management for a terminal device.
The method according to claim 22, wherein the capability of the protocol prefix management comprises at least one of a server function and a proxy function for the protocol prefix management.
The method according to claim 22 or 23, further comprising:

determining, based at least in part on the capability information, whether to enable the capability of the protocol prefix management of the first network node.
The method according to claim 24, further comprising:

transmitting an activation instruction to the first network node to indicate the first network node to enable a proxy function for the protocol prefix management, in response to determination of enabling the proxy function of the first network node for the terminal device.
The method according to claim 25, further comprising:

providing an indicator of a network instance for the terminal device to the first network node.
The method according to claim 25 or 26, further comprising:

informing the first network node of an identifier of a server which is able to allocate a protocol prefix to the terminal device.
The method according to any of claims 25-27, further comprising:

receiving a protocol prefix allocated to the terminal device from the first network node.
The method according to any of claims 25-28, further comprising:

obtaining protocol interface information for the terminal device from the first network node.
The method according to claim 24, further comprising:

transmitting an activation instruction to the first network node to indicate the first network node to enable a server function for the protocol prefix management, in response to determination of enabling the server function of the first network node for the terminal device.
The method according to claim 30, further comprising:

providing a protocol prefix allocated to the terminal device to the first network node.
The method according to claim 31, further comprising:

transmitting to the first network node one or more protocol configuration parameters for the terminal device, wherein the one or more protocol configuration parameters are provisioned by at least one of the second network node and a server which allocates the protocol prefix to the terminal device.
The method according to any of claims 31-32, further comprising:

obtaining protocol interface information for the terminal device from the first network node.
The method according to any of claims 31-33, further comprising:

receiving a request for prefix renewal information of the terminal device from the first network node; and

transmitting the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device.
The method according to any of claims 31-34, wherein the protocol prefix allocated to the terminal device comprises a protocol prefix for a packet data network connection.
The method according to claim 35, further comprising:

receiving a request for prefix delegation information of the terminal device from the first network node; and

transmitting the prefix delegation information to the first network node to indicate a delegating prefix for the terminal device.
The method according to any of claims 25-36, further comprising:

transmitting a deactivation instruction to the first network node, in response to release of a connection associated with the protocol prefix allocated to the terminal device, wherein the deactivation instruction indicates the first network node to disable the enabled capability of the protocol prefix management for the terminal device.
The method according to any of claims 22-37, wherein the protocol prefix management comprises internet protocol version 6 prefix management.
The method according to any of claims 22-38, wherein the first network node comprises a packet data network gateway user plane function and the second network node comprises a packet data network gateway control plane function.
A method performed by a terminal device, comprising:

transmitting a request for prefix allocation information of the terminal device to a first network node, wherein the first network node is indicated by a second network node to enable a capability of protocol prefix management for the terminal device; and

receiving the prefix allocation information from the first network node, wherein the prefix allocation information comprises a protocol prefix allocated to the terminal device.
The method according to claim 40, wherein the capability of the protocol prefix management comprises one of a server function and a proxy function for the protocol prefix management.
The method according to claim 40 or 41, wherein the prefix allocation information further comprises one or more protocol configuration parameters for the terminal device provisioned by at least one of:

the first network node;

the second network node; and

a server which allocates the protocol prefix to the terminal device.
The method according to any of claims 40-42, further comprising:

receiving prefix renewal information from the first network node to renew the protocol prefix allocated to the terminal device.
The method according to claim 43, wherein the prefix renewal information is provisioned by at least one of:

the first network node;

the second network node; and

a server which allocates the protocol prefix to the terminal device.
The method according to any of claims 40-44, wherein the protocol prefix allocated to the terminal device comprises a protocol prefix for a packet data network connection.
The method according to claim 45, further comprising:

transmitting a request for prefix delegation information of the terminal device to the first network node; and

receiving the prefix delegation information from the first network node, wherein the prefix delegation information comprises a delegating prefix for the terminal device.
The method according to claim 46, wherein the delegating prefix for the terminal device is allocated by one of the second network node and a server which is able to allocate the delegating prefix to the terminal device.
The method according to claim 46 or 47, wherein the prefix delegation information indicates the protocol prefix for the packet data network connection as an excluded prefix.
The method according to any of claims 40-48, wherein the protocol prefix management comprises internet protocol version 6 prefix management.
The method according to any of claims 40-49, wherein the first network node comprises a packet data network gateway user plane function and the second network node comprises a packet data network gateway control plane function.
A method performed by a server, comprising:

receiving a request for a protocol prefix for a terminal device from a first network node, wherein the first network node is indicated by a second network node to enable a capability of protocol prefix management for the terminal device; and

transmitting the protocol prefix allocated to the terminal device by the server to the first network node.
The method according to claim 51, wherein the capability of the protocol prefix management comprises a proxy function for the protocol prefix management.
The method according to claim 51 or 52, further comprising:

receiving a request for one or more protocol configuration parameters for the terminal device from the first network node; and

transmitting the one or more protocol configuration parameters for the terminal device to the first network node.
The method according to any of claims 51-53, further comprising:

receiving a request for prefix renewal information of the terminal device from the first network node; and

transmitting the prefix renewal information to the first network node to renew the protocol prefix allocated to the terminal device.
The method according to any of claims 51-54, wherein the protocol prefix allocated to the terminal device comprises a protocol prefix for a packet data network connection.
The method according to claim 55, further comprising:

receiving a request for prefix delegation information of the terminal device from the first network node; and

transmitting the prefix delegation information to the first network node, wherein the prefix delegation information comprises a delegating prefix for the terminal device.
The method according to any of claims 51-56, wherein the protocol prefix management comprises internet protocol version 6 prefix management.
The method according to any of claims 51-57, wherein the first network node comprises a packet data network gateway user plane function and the second network node comprises a packet data network gateway control plane function.
An apparatus, comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the apparatus at least to perform the method according to any one of claims 1-21.
An apparatus, comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the apparatus at least to perform the method according to any one of claims 22-39.
An apparatus, comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the apparatus at least to perform the method according to any one of claims 40-50.
An apparatus, comprising:

one or more processors; and

one or more memories comprising computer program codes,

the one or more memories and the computer program codes configured to, with the one or more processors, cause the apparatus at least to perform the method according to any one of claims 51-58.
A computer-readable medium having computer program codes embodied thereon for use with a computer, wherein the computer program codes comprise codes for performing the method according to any one of claims 1-58.