WO2009009938A1

WO2009009938A1 - A method for routing when a service is activated by a mobile terminal in a radio network

Info

Publication number: WO2009009938A1
Application number: PCT/CN2007/003865
Authority: WO
Inventors: Zaifeng Zong; Jinguo Zhu
Original assignee: Zte Corporation
Priority date: 2007-07-18
Filing date: 2007-12-28
Publication date: 2009-01-22
Also published as: CN101257707B; CN101257707A

Abstract

A method for routing when a service is activated by a mobile terminal in a radio network is disclosed, and the method includes: a mobile terminal transmitting identification information and service request message to a radio access network unit, the identification information includes MME ID, Pool ID and Public Land Mobile-communication Network (PLMN) ID; after the radio access network unit receiving the service request message, if deciding that the Pool ID in the identify information is the ID of the serving CN node pool connecting to the radio access network unit, and the serving CN node pool belongs to the PLMN indicated by the PLMN ID, and the MME ID is valid, the radio access network unit inquiring the serving CN node serving the mobile terminal currently according to the MME ID, Pool ID and PLMN ID, and transmitting the service request message of the terminal to the serving CN node. The present invention could adapt the requirement of the whole IP intercommunication between the radio access system and the CN.

Description

Routing method for mobile terminal to activate service in wireless network

Technical field

The present invention relates to a wireless network, and more particularly to a routing method when a mobile terminal activates a service in a wireless network.

Background technique

A method for jointly managing a group of radio network controllers (RNCs) by a core network node, which is called a "pool" concept, is described in Release 5 (hereinafter referred to as R5) of the WCDMA. A core network node pool is defined as: An MS (Mobile Station) roaming does not have to change the area of the Serving CN Node; a pool is served by one or more core network service nodes; RNC managed All cells belong to the same pool.

In R5, NRI (Network Resource Identifier) is used to identify different core network service nodes. When the mobile terminal registers for the first time in a pool, the RNC allocates a core network service node according to the load sharing principle, and sends a registration request message of the mobile terminal to the core network service node. After successful registration, the core network service node sends its corresponding NRI to the mobile terminal, and the mobile terminal saves the NRI.

A mapping table of NRI to core network service node IP addresses is configured in all RNCs in the pool. When the mobile terminal again sends a Non-Access Stratum message (NAS) in the pool, the mobile terminal carries the NRI in the message. The R C searches the IP address of the core network service node from the configured mapping table according to the NRI, and forwards the non-access stratum message (NAS message) from the mobile terminal to the core network service node.

In R5, in order to be compatible with previous versions (R99 and R4), the NRI is planned to be part of the TMSI (Temporary Mobile Subscriber Identity). This limits the number of users managed by a pool to no more than 2 ^TMSI . Also, a portion of the TMSI is used as other management functions, such as a visitor register (VLR) restart flag, etc., and the number of users actually managed by the pool is less than 2 ^TMSI . This limits the expansion of the pool.

And, in R5, the mapping table between the NRI and the core network service node IP address is in the RNC. Configured. The configuration workload increases with the increase of the RNC. The configuration workload is the product of the number of RNCs and the number of core network service nodes, which also limits the expansion of the pool.

This routing method in R5 can still adapt to the requirements of 3G (third generation mobile communication system), because the connectivity between RNC and core network service nodes is actually limited in 3G networks. However, with the deepening of IP, the wireless access system and the core network can achieve full IP interworking, and the pool can be configured to be large, so as to achieve more resource sharing. At present, the current routing method can no longer meet the needs. .

Summary of the invention

The technical problem to be solved by the present invention is to provide a routing method for a mobile terminal to activate a service, which can adapt to the requirement of the IP access between the wireless access system and the core network, and can greatly expand the number of users managed by the pool.

In order to solve the above technical problem, the present invention provides a routing method for a mobile terminal to activate a service in a wireless network, where the mobile terminal saves a core network service node identifier MME ID and a core network service node pool identifier Pool ID in advance, the method Includes the following:

The mobile terminal sends the identification information and the service request message to the radio access network unit, where the identifier information includes the MME ID, the Pool ID, and the public land mobile network identifier PLMN ID;

After receiving the service request message, the radio access network unit determines that the Pool ID in the identifier information is an ID of a core network service node pool connected to the radio access network unit, and the core network service node If the pool belongs to the public land mobile network specified by the PLMN ID, and the MME ID is valid, the radio access network unit queries the core network service node currently serving the mobile terminal according to the MME ID, the Pool ID, and the PLMN ID, and the The service request message of the terminal is sent to the core network service node.

Further, the identification information and the service request message sent by the mobile terminal to the radio access network unit are transmitted by using a radio resource control message between the mobile terminal and the radio access network unit.

Further, the query is currently the mobile according to the MME ID, the Pool ID, and the PLMN ID. The core network service node of the terminal service includes: the radio access network unit forms a domain name of the core network service node according to the PLMN ID, the Pool ID, and the MME ID, and queries the IP address of the core network service node according to the domain name.

Further, the domain name of the core network service node generated by the radio access network unit is MME ID.Pool ID.PLMN ID.

Further, the core network service node is a mobility management entity, and the radio access network unit is an evolved node B.

Further, the mobile terminal saves the MME ID and the Pool ID when registering or when the tracking area is updated.

Further, the Pool ID is an identifier of a tracking area managed by the core network service node pool, or an identifier independent of the tracking area identifier.

Further, the validity of the PLMN ID means that the value of the PLMN ID is not empty, and the radio access network element belongs to the public land mobile network identified by the PLMN ID; the validity of the pool ID means that the pool ID value is not empty. And the core network service node pool is a pool ID of a core network service node pool that manages the radio access network unit, and the PLMN ID is consistent with a PLMN ID of a core network service node pool corresponding to the pool ID; the MME If the ID is valid, the MME ID value is not empty, and the corresponding Pool ID is valid.

Further, the radio access network unit may cache the identification information and the corresponding relationship of the core network service node locally, so as to quickly query when the connection is continued.

Further, if the MME ID space in the pool of the plurality of core network service nodes connected to the radio access network unit does not overlap, the radio access network unit may ignore the pool ID when querying the core network service node, directly according to MME ID query.

The present invention provides a method for efficiently routing a message to a core network service node by a radio access network element in a network consisting of a plurality of radio access network elements and a plurality of core network service nodes. The solution of the invention is based on the IP architecture and can adapt to the needs of the all-IP interworking between the wireless access system and the core network. The present invention employs a new parameter: A TMSI-independent identifier MME ID is used to identify the core network serving node in the pool, and the TMSI field is no longer used as the identifier, so there is no limit to the number of users managed by the pool. In addition, it can be done without a wireless access network In the meta-configuration map, the radio access network RAN queries a centralized control unit to obtain the IP address of the core network service node, which reduces the workload of the radio access network unit and saves system resources. BRIEF abstract

1 is a network structure diagram of a plurality of radio access network units and a plurality of core network nodes; FIG. 2 is a flowchart of the first embodiment of the present invention;

Figure 3 is a flow chart of a second embodiment of the present invention;

Figure 4 is a flow chart of a third embodiment of the present invention. Preferred embodiment of the invention

The invention will be further described in detail below with reference to the drawings and specific embodiments.

The present invention provides the following improvements to the problems existing in R5:

First, the core network service node in a pool is no longer identified by the TMSI field, but is identified by a TMSI-independent identifier MME ID (MME Identifier);

Secondly, the mapping between the MME ID and the IP address of the core network service node is not required to be manually configured in the radio access network unit, but the radio access network unit RAN queries a centralized control unit (such as a DNS server or a resource management server). ) Obtain the IP address of the core network service node.

To speed up the query of the IP address of the core network service node, the radio access network unit may cache the IP address of the core network service node corresponding to a certain identification information obtained from the centralized control unit at the local location for subsequent quick query use. The radio access network unit may first query the IP address of the corresponding core network service node according to the MME ID, the Pool ID, and the PLMN ID from the local cache, and if not queried from the cache, query the centralized control unit.

Moreover, even if the IP address of the core network service node can be queried by using the centralized control unit, the present invention does not exclude that the wireless access network unit locally configures the mapping relationship in a local manner, and queries the core from the local configuration data. The IP address of the web service node.

The global identifier of the core network service node in this embodiment is determined by the public land mobile network identifier (PLMN ID), the core network service node pool identifier (Pool ID), and the core network service in the pool. The identifiers of the nodes (MME ID) are composed together.

When the core network node pools overlap each other, that is, the radio access network unit is connected to multiple core network service node pools belonging to the same PLMN, and the cores in the overlapping core network service node pools may be selected during actual network planning. The numbering spaces of the network serving nodes (MMEs) do not overlap, that is, the numbering of all core network serving nodes (MMDs) in these overlapping core network serving node pools is unique among overlapping pools. Through such planning, the radio access network unit can query the core network service node based only on the MME ID.

Referring to FIG. 1, a network structure diagram between a plurality of radio access network units and a plurality of core network nodes includes: a core network service node pool 100, a plurality of core network service nodes 101, 102, and 103, and a resource management server. 120, and a number of Radio Access Network Units (RANs) 110, 111, 112, 113. A core network service node pool 100 refers to a group of core network service nodes that jointly manage a group of radio access networks (such as the radio access network elements 110, 111, 112, 113 shown in the figure), as shown in the figure. The core network service node pool 100 includes core network service nodes 101, 102, 103. When the mobile terminal moves in the radio access network units 110, 111, 112, 113 managed by the core network service node pool 100, the core network service The node remains unchanged. A core network service node pool also manages a set of tracking areas (such as the tracking areas 130, 131, 132 shown in the figure), each tracking area corresponding to a tracking area identifier, Tracking Area ID (TAI) It is unique among the entire Public Land Mobile Network (PLMN). The Pool ID can be an identifier (TAI) of a tracking area it manages, or it can be an identifier that is independent of the tracking area identifier. The Pool ID and the PLMN ID can form the domain name of a core network service node pool, and uniquely identify the core network monthly service node pool.

When the radio access network unit receives the non-access stratum message (NAS message) sent by the mobile terminal in the idle state, it checks whether the identifier information is carried therein, and the identifier information includes the PLMN ID, the Pool ID, and the MME ID. The following different processes are taken depending on the validity of the identification information:

If the PLMN ID, the Pool ID, and the MME ID are both valid, the identifier information MME ID, Pool ID, and PLMN ID are grouped into the domain name of the core network service node of the mobile terminal, and the core network service is uniquely identified. node. According to the domain name, the radio access network unit queries the DNS server or the resource management server to obtain the IP address of the core network service node, thereby Communication, sending a non-access stratum message of the mobile terminal to the core network service node;

The radio access network unit forms an optional i or name of the core network service node domain name by combining the MME ID, Pool ID and PLMN ID: domain name = MME ID.Pool ID.PLMN ID.

2 If the PLMN ID and the Pool ID received by the radio access network unit are valid, but the received MME ID is invalid, the domain name of the core network service node pool is constructed, and the core network service of the radio access network unit is managed according to the domain name access. The resource management server corresponding to the node pool, the resource management server allocates a core network service node to the mobile terminal according to the load sharing principle, and the radio access network unit sends the non-access stratum message of the mobile terminal to the core network service node;

The foregoing resource management server may be an independently set server, or may be distributed in each core network service node;

3 If the PLMN ID received by the radio access network unit is valid, but the received Pool ID and MME ID are invalid, the Pool ID is first determined according to the PLMN ID (only one MME Pool of one PLMN is connected to one radio access network unit). Reconfiguring the domain name of the core network service node pool, accessing the resource management server corresponding to the core network service node pool according to the domain name, and assigning the core network service node by the resource management server, and the wireless access network unit will be the non-access layer of the mobile terminal The message is sent to the core network service node;

4 If the PLMN ID, Pool ID and MME ID received by the radio access network unit are invalid, a failure message is returned to the UE.

The valid PLMN ID is that the PLMN ID value is not NULL, and the radio access network element belongs to the public land mobile network identified by the PLMN ID; the valid pool ID means that the pool ID value is not ULL, and the core network The monthly service node pool is a pool ID of a core network service node pool that manages the radio access network unit, and the PLMN ID is consistent with the PLMN ID of the core network service node pool corresponding to the pool ID; the valid MME ID is The MME ID value is not NULL, and the corresponding Pool ID is valid. The radio access network unit can be managed by multiple core network service node pools at the same time, but the multiple core network service node pools managing the same radio access network unit are independent of each other and have no interaction.

After the core network service node successfully registers the mobile terminal, the MME ID of the core network service node and the core network service thereof are sent in a response message sent by the core network service node to the mobile terminal. The pool ID of the node pool and the corresponding PLMN ID of the public land mobile network are sent to the mobile terminal, so that the mobile terminal carries the latest MME ID, Pool ID and PLMN ID to the radio access network unit when the new service request is initiated next time. Enable the radio access network element to find its registered core network service node.

The non-access stratum message is a message between the mobile terminal and the core network service node, and the access message is

A message between the UE and the radio access network element. Between the radio access network element and the UE, non-access stratum messages are also transmitted through the access message. In order to save the trouble of the radio access network unit decoding the non-access stratum message, the MME ID, Pool ID, and PLMN ID are placed in the access message for transmission.

First embodiment

As shown in FIG. 2, this embodiment is a flow when the mobile terminal registers for the first time in the network. This embodiment is applied to System Architecture Evolution (SAE). The MME (Mobility Management Entity) in Figure 1 corresponds to the core network serving node in Figure 1, and the eNB (Evolved Node B) corresponds to Figure 1 The radio access network unit in FIG. 1 , the UE (user equipment) corresponds to the mobile terminal in FIG. 1 .

The registration process consists of the following steps:

Step 201: The attach request message of the UE is transmitted by using an initial direct transmission message of an RRC (Radio Resource Control) message between the UE and the eNB, where the initial direct transmission message includes an attach request message (non-access stratum message) between the UE and the MME. And the identifier information when the UE is last registered, the identifier information includes: an MME ID (Mobility Management Entity Identity), a Pool ID (Core Network Service Node Pool Identity), and a PLMN ID (Public Land Mobile Network Identity);

Since the UE is registered in the network for the first time when the attach request message is sent, the UE may set the MME ID and the Pool ID of the initial direct transmission message to NULL, that is, invalid, and the PLMN ID is set to the PLMN ID of the network selected by the UE; In the layer message (attach request message), the UE carries the MME ID, Pool ID and PLMN ID of the MME where the last registration is located, and optionally, the UE may also carry the TAI (Tracking Area ID) where the last registration is located.

Step 202: After receiving the initial direct transmission message, the eNB parses the identifier information, and determines whether the PLMN ID in the identifier information is valid. If yes, perform the next step, otherwise the eNB directly returns the loss. Responding to the UE, the registration process ends;

Step 203: If the eNB determines that the PLMN ID is valid, and the MME ID and the Pool ID are invalid, the eNB selects the MME pool corresponding to the PLMN according to the PLMN ID, and determines the Pool ID of the MME pool to be connected. The corresponding POOL ID of the multiple MME pools, and the PLMN ID corresponding to each POOL ID, generates a domain name of the MME pool, such as: Pool ID. PLMN ID, and the eNB accesses the resource management corresponding to the MME pool. a server, and the resource management server corresponding to the MME pool allocates an MME to the UE according to a load sharing principle;

The following two methods can be used to allocate the MME, as shown by the dashed boxes a and b in the figure.

the first method:

Al, the eNB sends an attach request message sent by the UE to the resource management server corresponding to the generated domain name;

A2, the resource management server allocates the MME to the UE according to the load sharing principle, and redirects the attach request message to the allocated MME, that is, directly sends the attach request message to the MME.

The resource management server can be one or more independently set servers, or it can be distributed among all MMEs in the MME pool. If the allocated MME is the resource management server itself, step A2 is not required.

The second method:

Bl, the eNB requests the resource management server to allocate an MME according to the generated domain name;

B2, the resource management server allocates the MME to the UE according to the load sharing principle;

At this point, the resource management server is one or more servers that are set up independently, and the functions of the server can be integrated into the domain name resolution server DNS.

B3, the eNB forwards the attach request message received by the UE to the MME-eNB allocated by the resource management server to forward the message to the MME, first searches for the IP address of the MME, and then forwards the message.

Step 204: After receiving the attach request message, the MME determines whether the attach request message carries a valid old Pool ID (or old TAI) and old MME ID, if yes, go to the next step, otherwise, go to step 207;

Step 205: The MME parses the domain name of the old MME where the UE was last registered according to the old pool ID (or the old TAI) and the old MME ID carried in the attach request message, and obtains the old MME according to the domain name through DNS resolution. IP address, and send a request to the old MME to transmit a UE context message, where the UE context message includes user information such as a user key and a subscription attribute; since one MME Pool manages a group of TAs, and the TA is globally unique, The TAI can be used to identify the MME Pool when the TAs of the two MME pools do not overlap.

Step 206: The old MME sends the context message of the UE to the MME at this time;

Step 207: Determine, according to the requirement, whether the user needs to be authenticated (for example, if the user is a new user, or the last authentication is about to expire), if yes, the MME authenticates the UE, and performs the next step, otherwise, directly executes Next step;

Step 208: The MME registers itself with the home subscriber server HSS to serve the UE. Step 209: After receiving the registration message of the MME, the HSS sends a command to delete the user context message to the old MME.

Step 210: The old MME deletes or identifies the user context as not existing.

Step 211: The HSS inserts user subscription information into the MME.

Step 212: Establish a default IP bearer under the control of the MME (that is, assign an IP and establish a connection); this step also requires the participation of the core network user plane unit, which is not within the scope of the present invention and will not be described.

Step 213: The MME sends a registration confirmation message (or an attach accept message) to the UE. If the core network serving node determines that the MME ID has changed (that is, the MME ID in the non-access message sent by the mobile terminal does not match), the core The network service node carries the latest identification information, including the MME ID, the Pool ID, or the PLMN ID, in the acknowledgement message;

Step 214: After receiving the registration confirmation message, the UE saves the identifier information therein, and returns a registration success confirmation (or an attachment acceptance confirmation message) to the MME.

The UE saves the identification information therein so that the non-access stratum message can be correctly routed the next time the access is made. To the MMEo

Second Embodiment As shown in FIG. 3, this embodiment is a flow when a mobile terminal maintains a service in an idle state while maintaining a range of a wireless access network managed by the same MME pool. In this process, the UE has saved a valid MME ID and Pool ID before initiating a service request. The steps are as follows:

Step 301: The service request message of the UE is transmitted by using an initial direct transmission message of the RRC message between the UE and the eNB, where the initial direct transmission message includes a service clearing message (non-access stratum message) and an identifier of the last registration of the UE. Information, the identifier information includes an MME ID, a Pool ID, and a PLMN ID;

The identification information is carried in the initial direct transmission message so that the eNB does not need to parse the non-access layer message (here, the service request) when searching for the path.

Step 302: After receiving the initial direct transmission message, the eNB parses the identifier information, and determines that the Pool ID in the identifier information is an ID of a certain MME pool connected to the eNB, and the MME pool belongs to the PLMN specified by the PLMN ID. And the MME ID is not NULL, the eNB composes the domain name of the MME according to the PLMN ID, the Pool ID, and the MME ID, such as: MME ID.Pool ID.PLMN ID; Step 303, the eNB finds the MME according to the domain name. The domain name is translated to the IP address and is located in the MME, and the UE is associated with the MME (for example, the RRC is bound to the signaling link), and the service request message of the UE is sent to the MME;

After receiving the service request message, the MME authenticates the UE as needed. Subsequent non-access stratum messages are forwarded directly between the MME and the UE, and the eNB does not need to resolve the domain name again.

Third Embodiment As shown in Fig. 4, this embodiment is a tracking area update procedure when a mobile terminal moves to an area of a radio access network managed by another MME pool in an idle state. In this process, the Pool ID saved in the UE is not the ID of the MME pool to be accessed. Therefore, the Pool ID and MME ID saved in the UE are invalid. The steps are as follows:

Step 401: When the UE detects that the tracking area changes (the tracking area list broadcasted by the cell and the UE) The tracked area update request message is sent, and the tracking area update request message of the UE is transmitted by the initial direct transmission message of the RRC message between the UE and the eNB, and the initial direct transmission message includes the tracking area update request message. (non-access stratum message) and identification information when the UE is last registered, the identifier information includes: MME ID, ? 001 10 and? ^ ;

The tracking area update request message is sent to the MME, and the message is transmitted to the eNB through an initial direct transmission message of the RRC message between the UE and the eNB.

Step 402: After receiving the initial direct transmission message, the eNB parses the identifier information, and determines whether the PLMN ID in the identifier information is valid. If yes, perform the next step, otherwise the eNB directly returns a failure response to the UE, and the registration process ends;

Step 403: The eNB determines that the PLMN ID is valid, and the MME ID and the Pool ID are invalid, according to the PLMN.

The ID determines the pool ID of the MME pool to be connected, and generates a domain name, such as: Pool ID. PLMN ID, where the eNB accesses the resource management server corresponding to the MME pool, and the resource management server gives the resource management server according to the load sharing principle. The UE allocates an MME;

In this embodiment, the Pool ID is different from the Pool ID of the eNB in the same PLMN, and the MME pool is changed. The MME ID and the Pool ID are not NULL, but are still invalid. The MME needs to be re-allocated.

There are two methods for assigning MMEs, as shown by the dashed boxes a and b in the figure.

the first method:

Al, the eNB sends a tracking update request message sent by the UE to the resource management server corresponding to the generated domain name;

A2. The resource management server allocates the MME to the UE according to the load sharing principle, and redirects the tracking update request message to the allocated MME.

The second method:

B2, the resource management server allocates the MME to the UE according to the load sharing principle: At this point, the resource management server is one or more servers that are set up independently. The functionality of the server can be integrated into the DNS of the domain name resolution server.

B3. The eNB forwards the tracking update request message received by the UE to the MME allocated by the resource management server.

When the eNB forwards the message to the MME, it first searches for the IP address of the MME in the centralized control unit, and then forwards the message.

Step 404, after receiving the tracking update request message, the MME determines whether the tracking old update request message carries a valid old Pool ID (or old TAI) and the old MME ID, and if so, performs the next step, otherwise, step 407;

Step 405: The MME parses the IP address of the old MME where the UE was last registered according to the old Pool ID (or the old TAI) and the old MME ID in the tracking update request message, and sends a request to transmit the UE context message to the Old MME.

Step 406: The old MME sends the context message of the UE to the MME at the current time, where the UE context message includes user information such as a user key and a subscription attribute.

Step 407: Determine, according to requirements, whether the user needs to be authenticated (for example, if the user is a new user, or the last authentication is about to expire), if yes, the new MME authenticates the UE, and performs the next step, otherwise, directly Carry out the next step;

Step 408: The MME registers with the HSS to serve the UE.

Step 409: After receiving the registration message of the MME, the HSS sends a command to delete the user context to the old MME.

Step 410: The old MME deletes or identifies the user context as not existing.

Step 411: The HSS inserts user subscription information into the MME.

Step 412: The MME sends a tracking area update accept message to the UE, where the message carries the identification information, including the MME ID, the Pool ID, or the PLMN ID.

Step 413: After receiving the tracking area update accept message, the UE saves the identifier information in the tracking information.

The MME confirms that the tracking area update is successful.

The UE saves the identification information therein so that the non-access stratum message can be correctly routed the next time the access is made. Go to the MME.

It is a matter of course that the invention may be embodied in various other forms without departing from the spirit and scope of the invention.

Claims

Claim

A routing method for a mobile terminal to activate a service in a wireless network, wherein the mobile terminal saves a core network service node identifier MME ID and a core network service node pool identifier pool ID in advance, wherein the method includes the following content:

2. The method according to claim 1, wherein the identification information and the service request message sent by the mobile terminal to the radio access network unit are controlled by radio resources between the mobile terminal and the radio access network unit. Messaging.

The method according to claim 1, wherein the querying the core network service node currently serving the mobile terminal according to the MME ID, the Pool ID, and the PLMN ID comprises: the radio access network unit according to the PLMN ID, The Pool ID and the MME ID form the domain name of the core network service node, and the IP address of the core network service node is queried according to the domain name.

4. The method according to claim 3, wherein the domain name of the core network service node generated by the radio access network unit is MME ID.Pool ID.PLMN ID.

The method according to claim 1, wherein the core network service node is a mobility management entity, and the radio access network element is an evolved node.

6. The method according to claim 1, wherein the mobile terminal saves the MME ID and the Pool ID when registering or when the tracking area is updated.

7. The method according to claim 6, wherein the Pool ID is an identifier of a tracking area managed by a core network service node pool, or an identifier independent of the tracking area identifier.

The method according to claim 1, wherein the PLMN ID is valid means that the PLMN ID value is not empty, and the radio access network element belongs to the public land mobile network identified by the PLMN ID; The pool ID is valid, and the pool ID is not empty, and the core network service node pool is a pool ID of a core network service node pool that manages the radio access network unit, and the core corresponding to the pool ID and the pool ID The PLMN ID of the network service node pool is consistent; the MME ID is valid, and the MME ID value is not empty, and the corresponding pool ID is valid.

The method according to claim 1, wherein the radio access network unit can cache the correspondence between the identification information and the core network service node locally, so as to quickly query when the connection is continued.

10. The method according to claim 1, wherein if the MME ID spaces in the plurality of core network serving node pools simultaneously connected to the radio access network unit do not overlap, the radio access network unit queries the core network. The service ID can ignore the Pool ID and query directly according to the MME ID.