CN103974237B - Motion management method and entity - Google Patents

Abstract

This application provides a mobility management method and entity, which are applied to an LTE network where MMEs are deployed centrally. The method includes: configuring the corresponding relationship between the UE location information and the IP address of the DNS server in the area where the UE is located on the MME; the MME receives the mobility management message sent by the UE, the message carries the UE location information, and the MME finds the UE location information according to the UE location information. The IP address of the matching DNS server; the MME constructs the FQDN according to the UE-related information, and sends an N record query request message to the matching DNS server. The message carries the FQDN. According to the S-GW or P-GW list and local rules returned by the DNS server Select a S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; MME initiates a move to the selected S-GW or P-GW sex management process. The invention realizes the mobility management in the LTE network where the MME is deployed centrally.

Description

Mobility management method and entity

technical field

The present application relates to the field of wireless technology, in particular to a mobility management method and entity.

Background technique

In order to enhance the competitiveness of future networks, the 3rd Generation Partnership Project (3GPP) launched the Long Term Evolution (LTE, Long Term Evolution) and System Architecture Evolution (SAE, System Architecture Evolution) in the R8 phase. Standard formulation work for important projects. In terms of the core network, a new pure packet domain core network architecture has been introduced.

Figure 1 is a schematic diagram of the SAE system architecture introduced by 3GPP. As shown in Figure 1, its main network elements are as follows:

User equipment (UE, User Equipment);

Evolved Universal Terrestrial RadioAccess Network (E-UTRAN, Evolved Universal Terrestrial RadioAccess Network): access network, which mainly implements radio resource management functions;

Mobility Management Entity (MME, Mobility Management Entity): Provides the main control for LTE access network, and is responsible for the mobility management of the core network, including paging, security control, bearer control of the core network and terminal in idle state mobility control, etc.;

Serving-GateWay (S-GW, Serving-GateWay): Responsible for the transmission, forwarding and routing switching of UE user plane data, and also serves as a mobility anchor point for mutual transmission of user plane messages between evolved base stations (eNodeBs), and serves as a gateway for LTE and Mobility anchor for other 3GPP technologies;

Packet Data Network Gateway (P-GW, Packet Data Network Gateway): It is a gateway for Packet Data Network (PDN, Packet Data Network), mainly responsible for user-based packet filtering function, legal interception function, UE's Internet Protocol (IP, Internet Protocol) address allocation function, packet marking, billing, gate control, quality of service (QoS, Quality of Service) control, bearer control, etc. in the uplink and downlink transport layers;

Home Subscriber Server (HSS, Home Subscriber Server): mainly responsible for user subscription information management;

The domain name system (DNS, Domain Name System) server is not reflected in the 3GPP standard network architecture diagram. It is connected to the MME during actual networking and is mainly responsible for the address resolution of LTE core network elements.

Figure 2 is a schematic diagram of the current network deployment structure of the existing LTE network. As shown in Figure 2, in the current network deployment solution, the HSS is deployed in a centralized manner to uniformly store user data on the entire network. MME, S-GW, P-GW, and DNS servers are all deployed in different provinces. The DNS server deployed in the province stores the IP addresses of the P-GW, S-GW, and MME in the province and the related fully qualified domain name (FQDN, FullyQualified Domain Name) mapping table, and the DNS server resolves the S -IP addresses of network elements such as GW, P-GW, and MME

The method for the MME to select the DNS server is as follows: During the UE user initial attachment, tracking area update and other processes, the MME needs to select the P-GW and S-GW serving the user. Specifically, when the user initially attaches, the MME will select the DNS server in the province directly connected to it, and then construct a format such as <APN-NI>.apn.epc based on the user's access point name (APN, Access Port Name). The FQDN of mnc<MNC>.mcc<MCC>.3gppnetwork.org, and then initiates an N record query request to the selected DNS server, and the DNS server returns the P-GW list, and the MME selects the P-GW according to the local rules and the parameters in the returned list. -GW, and further initiate an A record query request to obtain the specific IP address of the P-GW.

The way MME selects the DNS server and the query method in the process of tracking area update, handover and reselection is similar to the process of user initial attachment, but the constructed FQDN format is slightly different.

Among them, due to the hierarchical setting of the DNS server, the provincial DNS server will send the domain name that it cannot resolve to the upper-level DNS server, and the upper-level DNS server will resolve it.

With the rapid development of chip technology, the processing capacity of equipment has also increased, and the capacity of equipment has also increased significantly. The shortcomings of provincial deployment will gradually become prominent.

The LTE/Evolved Packet Core (EPC, Evolved Packet Core) network has a complete control and bearer separation architecture, and the MME is a signaling plane network element, which is not sensitive to delay. With the continuous expansion of MME capacity, centralized deployment of MME will become possible. Centralized deployment of MME can save site costs and enable unified maintenance and management. Set up a district-level management team to conduct unified management and maintenance of the equipment deployed in the district, which can realize the reduction of personnel, improve the efficiency of equipment construction, commissioning, and troubleshooting, and uniformly handle customer complaints and distribute customer complaint handling tasks. However, because users are more sensitive to experiments, in order to ensure user experience, the data plane network elements S-GW and P-GW still need to be deployed in different provinces, so as to be closer to the user plane and reduce data delay. At this time, the user's mobility management is implemented by the MME deployed nationwide, but the user's data plane data is still processed from the local S-GW and P-GW, and is directly routed to the Internet by the P-GW.

Since most of the DNS servers in the current second-generation mobile communication standard (2G)/third-generation mobile communication standard (3G) network already support the N record query method required by the LTE network, when MME is deployed in a centralized manner, it is necessary to save money. For investment considerations, the DNS server can keep the existing network structure unchanged, that is, it can still be deployed in different provinces.

Figure 3 is a schematic diagram of the network topology structure of the existing MME centralized deployment. As shown in Figure 3, under the network architecture of the centralized MME deployment, the MME serves multiple provinces at the same time. How to find the S-GW and PGW became a problem. The MME only needs to first find the DNS server of the province where the user is currently located, and then construct the FQDN according to the APN information, and query the corresponding PGW IP address in the DNS server of the corresponding province. There is currently no clear solution for how the MME finds the DNS server in the corresponding province, which makes it impossible to implement mobility management in the LTE network where the MME is deployed centrally.

Contents of the invention

The application provides a mobility management method, an MME, a DNS proxy server, and an LTE system, so as to implement mobility management in an LTE network where the MME is deployed centrally.

A mobility management method, applied to a long-term evolution LTE network deployed centrally by a mobility management entity MME, the method comprising:

Configure the correspondence between the location information of the user equipment UE and the Internet Protocol IP address of the domain name system DNS server in the area where the UE is located on the MME;

The MME receives the mobility management message sent by the UE, which carries the UE location information. According to the UE location information, the MME finds the matching DNS server IP address in the configured correspondence between the UE location information and the DNS server IP address. address;

The MME constructs a fully qualified domain name FQDN according to UE-related information, and sends an N record query request message to the matching DNS server. The message carries the FQDN. According to the serving gateway S-GW or packet data Rule, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; MME sends the selected S-GW or P-GW Initiate the mobility management process.

The UE location information is an eNodeB identifier or a tracking area identifier TAI of an area where the UE is located.

The mobility management message is an attach message, or a tracking area update message, or a handover reselection message.

A mobility management method, applied to an LTE network deployed centrally by MME, where a DNS proxy server is deployed in the LTE network, and the DNS proxy server is configured with IP addresses and geographic location information of DNS servers in each area, and the MME The IP address of the DNS proxy server is configured, the method includes:

The MME receives the mobility management message sent by the UE, which carries UE location information; the MME sends a DNS query request message to the DNS proxy server, which carries the UE location information, and at the same time carries the UE-related information required to construct the FQDN, so that the DNS proxy server According to the location information of the UE, the server finds the IP address of the DNS server that matches in the configured DNS server IP addresses and geographical location information of each area, and the DNS proxy server constructs the UE-related information according to the DNS query request message. FQDN, send an N record query request message to the matching DNS server, and the message carries the FQDN;

The MME receives the S-GW or P-GW list sent by the DNS server, and the S-GW or P-GW list is obtained by the DNS server according to the FQDN carried in the N record query request message;

MME selects an S-GW or P-GW according to the S-GW or P-GW list returned by the DNS server and local rules, and initiates an A record query request to the DNS server to obtain the selected S-GW or P-GW IP address; MME initiates the mobility management process to the selected S-GW or P-GW.

The UE location information is an eNodeB identifier or a tracking area identifier TAI of an area where the UE is located.

The mobility management message is an attach message, or a tracking area update message, or a handover reselection message.

An MME, located in the LTE network where the MME is deployed centrally, the MME includes:

Configuration module: save the corresponding relationship between the UE location information and the IP address of the DNS server in the area where the UE is located;

Mobility management module: Receive the mobility management message sent by the UE, the message carries the UE location information, according to the UE location information, find the matching relationship between the UE location information and the IP address of the DNS server saved by the configuration module The IP address of the DNS server; construct the FQDN according to UE-related information, and send an N record query request message to the matching DNS server, the message carries the FQDN, and according to the S-GW or P-GW list and local rules returned by the DNS server, Select an S-GW or P-GW, initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiate mobility to the selected S-GW or P-GW management process.

The UE location information stored in the configuration module is the eNodeB identifier or TAI of the area where the UE is located;

The UE location information carried in the mobility management message received by the mobility management module is the eNodeB identifier or TAI of the area where the UE is located.

The mobility management message received by the mobility management module is an attach message, or a tracking area update message, or a handover reselection message.

A kind of MME, is located in the LTE network that MME centrally deploys, and DNS proxy server is deployed in described LTE network, and the IP address and geographical position information of the DNS server of each area are configured in DNS proxy server, and this MME comprises:

Configuration module: save the IP address of the DNS proxy server;

Mobility management module: Receive the mobility management message sent by the UE, the message carries UE location information, and sends a DNS query request message to the DNS proxy server according to the IP address of the DNS proxy server saved by the configuration module, and the message carries UE location information , carrying the UE-related information required to construct the FQDN, so that the DNS proxy server can find the IP address of the DNS server that matches in the configured IP addresses and geographic location information of the DNS servers in each area according to the UE location information, And the DNS proxy server constructs the FQDN according to the UE-related information in the DNS query request message, sends an N record query request message to the matching DNS server, and carries the FQDN in the message; receives the S-GW or P-GW list sent by the DNS server, the The above S-GW or P-GW list is obtained by the DNS server according to the FQDN carried in the N record query request message; according to the S-GW or P-GW list and local rules returned by the DNS server, select an S-GW The GW or P-GW initiates an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiates a mobility management process to the selected S-GW or P-GW.

The UE location information carried in the mobility management message received by the mobility management module is the eNodeB identifier or TAI of the area where the UE is located.

The mobility management message received by the mobility management module is an attach message, or a tracking area update message, or a handover reselection message.

A DNS proxy server, the DNS proxy server is located in the LTE network deployed centrally by the MME, the DNS proxy server includes:

Configuration module: save the IP address and geographical location information of the DNS server in each area;

DNS query module: Receive the DNS query request message sent by the MME, the message carries the UE location information, and at the same time carries the UE-related information required to construct the FQDN, according to the UE location information, in the DNS server of each area saved by the configuration module In the IP address and geographic location information, find the IP address of the matching DNS server, construct the FQDN according to the UE-related information in the DNS query request message, and send an N record query request message to the matching DNS server, carrying the FQDN in the message, so that DNS The server obtains the corresponding S-GW or P-GW list according to the FQDN, and sends the S-GW or P-GW list to the MME; wherein, the DNS query request message is received by the MME from the UE After the mobility management message carrying UE location information, it is sent to the DNS proxy server.

An LTE system in which MMEs are deployed centrally, the system includes:

UE: Send a mobility management message to the network side, which carries UE location information;

MME: Save the correspondence between UE location information and the IP address of the DNS server in the area where the UE is located; when receiving a mobility management message from the UE, according to the UE location information in the message, the stored UE location information and In the corresponding relationship of the DNS server IP address, find the IP address of the matching DNS server, construct the FQDN according to the relevant information of the UE, and send the N record query request message to the matching DNS server, the message carries the FQDN, according to the DNS server returned S-GW or P-GW list and local rules, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW, according to DNS The IP address of the selected S-GW or P-GW returned by the server initiates a mobility management process to the selected S-GW or P-GW.

The UE location information is the eNodeB identifier or TAI of the area where the UE is located.

The mobility management message is an attach message, or a tracking area update message, or a handover reselection message.

An LTE system in which MMEs are deployed centrally, the system includes:

UE: Send a mobility management message to the network side, which carries UE location information;

MME: Receive the mobility management message sent by the UE, which carries the UE location information, and sends a DNS query request message to the DNS proxy server, which carries the UE location information and UE-related information required to construct the FQDN; receives the DNS server According to the S-GW or P-GW list sent by the S-GW or P-GW list and local rules, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the selected Initiate a mobility management process to the selected S-GW or P-GW according to the IP address of the selected S-GW or P-GW returned by the DNS server;

DNS proxy server: save the IP address and geographic location information of the DNS server in each area; receive the DNS query request message, and according to the UE location information in the message, save the IP address and geographic location information of the DNS server in each area , the IP address of the matching DNS server is found, the FQDN is constructed according to the UE-related information in the DNS query request message, and the N record query request message is sent to the matching DNS server, and the FQDN is carried in the message.

The UE location information is the eNodeB identifier or TAI of the area where the UE is located.

The mobility management message is an attach message, or a tracking area update message, or a handover reselection message.

It can be seen from the above technical solution that the present invention realizes the mobility management for the LTE network deployed centrally by the MME.

Description of drawings

FIG. 1 is a schematic diagram of the system architecture of the SAE introduced by the existing 3GPP;

FIG. 2 is a schematic diagram of a live network deployment structure of an existing LTE network;

FIG. 3 is a schematic diagram of a network topology structure of an existing MME centralized deployment;

FIG. 4 is a flow chart of a method for mobility management in an LTE network where an MME is centrally deployed according to Embodiment 1 of the present invention;

FIG. 5 is a flow chart of a method for mobility management in an LTE network where an MME is centrally deployed according to Embodiment 2 of the present invention;

FIG. 6 is an example diagram of an LTE network in which an MME is centrally deployed according to Embodiment 2 of the present invention;

FIG. 7 is a schematic diagram of the composition of the MME provided by Embodiment 1 of the present invention;

FIG. 8 is a schematic diagram of the composition of the DNS proxy server provided by Embodiment 2 of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

FIG. 4 is a flow chart of a method for mobility management in an LTE network in which an MME is centrally deployed according to Embodiment 1 of the present invention. As shown in FIG. 4 , the specific steps are as follows:

Step 401: Pre-configure on the MME the corresponding relationship between the location information of the UE and the IP address of the DNS server in the area where the UE is located.

UE location information such as: eNodeB identity of the area where the UE is located, Tracking Area Identity (TAI, Tracking Area Identity) and so on.

In the present invention, the deployment method of the DNS server is the same as that of the prior art, which is a distributed deployment, for example, it can be deployed in different provinces.

Step 402: When the UE initiates a mobility management process, such as: initial attachment, tracking area update, handover reselection, etc., the mobility management message is sent to the centrally deployed MME through the S1 interface through the eNodeB in the area where the UE is located. Carries UE location information.

UE location information such as: eNodeB ID of the area where the UE is located, TAI, etc.

Step 403: According to the UE location information in the mobility management message, the MME finds the matching DNS server IP address in the locally configured correspondence between the UE location information and the DNS server IP address.

Step 404: The MME constructs the FQDN according to the UE's APN and other information, and sends an N record query request message to the matching DNS server.

The FQDN is carried in the N record query request message.

Step 405: The DNS server obtains the corresponding S-GW/P-GW list according to the FQDN carried in the N record query request message and returns it to the MME.

Step 406: MME selects an S-GW/P-GW according to the S-GW/P-GW list returned by the DNS server and local rules, and initiates an A record query request to the DNS server again to obtain the selected S-GW /IP address of the P-GW.

Step 407: The MME initiates a mobility management process to the selected S-GW/P-GW according to the IP address of the selected S-GW/P-GW, such as: attach, tracking area update, handover reselection and other processes.

The subsequent mobility management process is the same as that of the existing LTE network where the MME is deployed in a distributed manner.

FIG. 5 is a flow chart of a method for mobility management in an LTE network in which an MME is centrally deployed according to Embodiment 2 of the present invention. As shown in FIG. 5 , the specific steps are as follows:

Step 501: Create a new DNS proxy server in the LTE network, and configure the IP addresses and geographical location information of the DNS servers in each area in the DNS proxy server, and configure the IP address of the DNS proxy server on the MME.

The geographical location information of the DNS server is, for example, the eNodeB ID and TAI of the area where the DNS server is located.

FIG. 6 is an example diagram of an LTE network where MMEs are deployed centrally according to Embodiment 2 of the present invention. As shown in FIG. 6 , MMEs and DNS proxy servers are both deployed centrally.

Step 502: The UE initiates a mobility management process, such as initial attachment, tracking area update, handover and reselection, and sends a message to the centrally deployed MME through the eNodeB in the area where the UE is located, and the message carries UE location information.

UE location information such as: eNodeB ID, TAI, etc. of the area where the UE is located.

Step 503: The MME sends a DNS query request message to the DNS proxy server according to the IP address of the locally configured DNS proxy server. The message carries UE location information and information such as the UE's APN required to construct the FQDN.

Step 504: According to the location information of the UE in the DNS query request message, the DNS proxy server finds the IP address of the matching DNS server from the IP addresses and geographical location information of the DNS servers in each area configured locally, and searches for the IP address of the DNS server according to the DNS query request message. The FQDN is constructed from information such as the APN of the UE in , and an N record query request message is sent to the matching DNS server, and the FQDN is carried in the message.

Step 505: The DNS server obtains the corresponding S-GW/P-GW list according to the FQDN carried in the N record query request message and returns it to the MME.

Step 506: MME selects an S-GW/P-GW according to the S-GW/P-GW list returned by the DNS server and local rules, and initiates an A record query request to the DNS server to obtain the selected S-GW/P-GW IP address of the P-GW.

Step 507: The MME initiates a mobility management process to the selected S-GW/P-GW according to the IP address of the selected S-GW/P-GW, such as: attachment, tracking area update, handover reselection and other processes.

The subsequent mobility management process is the same as that of the existing LTE network where the MME is deployed in a distributed manner.

FIG. 7 is a schematic diagram of the composition of the MME provided by Embodiment 1 of the present invention. The MME is an MME deployed centrally in the LTE network. As shown in FIG. 7, the MME includes: a configuration module 71 and a mobility management module 72, wherein:

Configuration module 71: saving the corresponding relationship between the location information of the UE and the IP address of the DNS server in the area where the UE is located.

Mobility management module 72: Receive a mobility management message sent by UE, the message carries UE location information, according to the UE location information, find out the corresponding relationship between UE location information and DNS server IP address stored in configuration module 71 The IP address of the matching DNS server; construct the FQDN according to the UE’s APN and other information, and send an N record query request message to the matching DNS server. The message carries the FQDN. Rule, select an S-GW or P-GW, initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiate an A record query request to the selected S-GW or P-GW Mobility management process.

Wherein, the UE location information is, for example, the eNodeB identifier of the area where the UE is located, or the TAI.

Mobility management messages such as: attach message, or tracking area update message, or handover reselection message, etc.

The following is a schematic diagram of the composition of the MME provided by Embodiment 2 of the present invention. The MME is an MME deployed centrally in the LTE network, and a DNS proxy server is deployed in the LTE network. The DNS proxy server is configured with the IP address of the DNS server in each area. For address and geographic location information, the MME includes: a configuration module and a mobility management module, wherein:

Configuration module: save the IP address of the DNS proxy server.

Mobility management module: Receive the mobility management message sent by the UE, the message carries UE location information, and sends a DNS query request message to the DNS proxy server according to the IP address of the DNS proxy server saved by the configuration module, and the message carries UE location information , carrying information such as UE’s APN required to construct the FQDN, so that the DNS proxy server can find the IP address of the DNS server that matches in the configured IP addresses and geographical location information of the DNS servers in each area according to the location information of the UE. And the DNS proxy server constructs the FQDN according to the information such as the UE's APN in the DNS query request message, sends an N record query request message to the matching DNS server, and the message carries the FQDN; receives the S-GW or P-GW list sent by the DNS server , the S-GW or P-GW list is obtained by the DNS server according to the FQDN carried in the received N record query request message; according to the S-GW or P-GW list returned by the DNS server and local rules, select a The S-GW or P-GW initiates an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiates a mobility management process to the selected S-GW or P-GW.

Wherein, the location information of the UE is such as: the eNodeB identifier of the area where the UE is located, or TAI, etc.; the geographical location information of the DNS server is, for example: the eNodeB identifier of the area where the DNS server is located, or TAI, etc.

Mobility management messages such as: attach message, or tracking area update message, or handover reselection message, etc.

FIG. 8 is a schematic diagram of the composition of the DNS proxy server provided by Embodiment 2 of the present invention. The DNS proxy server is located in the LTE network where the MME is deployed centrally. As shown in FIG. 8 , the DNS proxy server includes: a configuration module 81 and a DNS query module 82 ,in:

Configuration module 81: saving the IP addresses and geographic location information of the DNS servers in each area.

DNS query module 82: Receive the DNS query request message sent by the MME, the message carries UE location information, and at the same time carries information such as the APN of the UE required to construct the FQDN, according to the UE location information, the DNS of each area saved in the configuration module 81 From the server's IP address and geographical location information, find the IP address of the matching DNS server, construct the FQDN according to the UE's APN and other information in the DNS query request message, and send an N record query request message to the matching DNS server, and the message carries FQDN, so that the DNS server can obtain the corresponding S-GW or P-GW list according to the FQDN, and send the S-GW or P-GW list to the MME; wherein, the DNS query request message is sent by the MME after receiving the UE After the mobility management message carrying the location information of the UE, it is sent to the DNS proxy server.

The embodiment of the present invention also provides an LTE system in which MMEs are deployed centrally. The system includes at least the UE and the MME provided in the first embodiment of the present invention, or at least includes the UE, the MME and the DNS proxy server provided in the second embodiment of the present invention.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the present invention. within the scope of protection.

Claims (19)

1. A mobility management method, applied in the long-term evolution LTE network deployed centrally by the mobility management entity MME, is characterized in that the method comprises: Configure the correspondence between the location information of the user equipment UE and the Internet Protocol IP address of the domain name system DNS server in the area where the UE is located on the MME; The MME receives the mobility management message sent by the UE, which carries the UE location information. According to the UE location information, the MME finds the matching DNS server IP address in the configured correspondence between the UE location information and the DNS server IP address. address; The MME constructs a fully qualified domain name FQDN according to UE-related information, and sends an N record query request message to the matching DNS server. The message carries the FQDN. According to the serving gateway S-GW or packet data Rule, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; MME sends the selected S-GW or P-GW A mobility management process is initiated, and the UE-related information includes: an access point name (APN) of the UE. 2. The method according to claim 1, wherein the UE location information is an eNodeB identifier or a tracking area identifier (TAI) of an area where the UE is located. 3. The method according to claim 1, wherein the mobility management message is an attach message, or a tracking area update message, or a handover reselection message. 4. A kind of mobility management method, is applied in the LTE network of MME centralized deployment, it is characterized in that, DNS proxy server is deployed in the described LTE network, and the IP address and the DNS server of each area are configured in the DNS proxy server For geographic location information, the IP address of the DNS proxy server is configured on the MME, and the method includes: The MME receives the mobility management message sent by the UE, which carries UE location information; the MME sends a DNS query request message to the DNS proxy server, which carries the UE location information, and at the same time carries the UE-related information required to construct the FQDN, so that the DNS proxy server According to the location information of the UE, the server finds the IP address of the DNS server that matches in the configured DNS server IP addresses and geographical location information of each area, and the DNS proxy server constructs the UE-related information according to the DNS query request message. FQDN, sending an N record query request message to the matching DNS server, the message carries the FQDN, and the UE-related information includes: the UE's access point name APN; The MME receives the S-GW or P-GW list sent by the DNS server, and the S-GW or P-GW list is obtained by the DNS server according to the FQDN carried in the N record query request message; MME selects an S-GW or P-GW according to the S-GW or P-GW list returned by the DNS server and local rules, and initiates an A record query request to the DNS server to obtain the selected S-GW or P-GW IP address; MME initiates the mobility management process to the selected S-GW or P-GW. 5. The method according to claim 4, wherein the UE location information is an eNodeB identifier or a tracking area identifier (TAI) of an area where the UE is located. 6. The method according to claim 4, wherein the mobility management message is an attach message, or a tracking area update message, or a handover reselection message. 7. A kind of MME, is located in the LTE network that MME deploys centrally, it is characterized in that, this MME comprises: Configuration module: save the corresponding relationship between the UE location information and the IP address of the DNS server in the area where the UE is located; Mobility management module: Receive the mobility management message sent by the UE, the message carries the UE location information, according to the UE location information, find the matching relationship between the UE location information and the IP address of the DNS server saved by the configuration module The IP address of the DNS server; construct the FQDN according to UE-related information, and send an N record query request message to the matching DNS server, the message carries the FQDN, and according to the S-GW or P-GW list and local rules returned by the DNS server, Select an S-GW or P-GW, initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiate mobility to the selected S-GW or P-GW In the management process, the UE-related information includes: the UE's access point name (APN). 8. The MME according to claim 7, wherein the UE location information stored in the configuration module is the eNodeB identifier or TAI of the area where the UE is located; The UE location information carried in the mobility management message received by the mobility management module is the eNodeB identifier or TAI of the area where the UE is located. 9. The MME according to claim 7, wherein the mobility management message received by the mobility management module is an attach message, or a tracking area update message, or a handover reselection message. 10. A kind of MME, located in the LTE network of MME centralized deployment, it is characterized in that, DNS proxy server is deployed in the described LTE network, and the DNS proxy server is configured with the IP address and geographic location information of the DNS server of each area, The MME includes: Configuration module: save the IP address of the DNS proxy server; Mobility management module: Receive the mobility management message sent by the UE, the message carries UE location information, and sends a DNS query request message to the DNS proxy server according to the IP address of the DNS proxy server saved by the configuration module, and the message carries UE location information , carrying the UE-related information required to construct the FQDN, so that the DNS proxy server can find the IP address of the DNS server that matches in the configured IP addresses and geographic location information of the DNS servers in each area according to the UE location information, And the DNS proxy server constructs the FQDN according to the UE-related information in the DNS query request message, sends an N record query request message to the matching DNS server, and carries the FQDN in the message; receives the S-GW or P-GW list sent by the DNS server, the The above S-GW or P-GW list is obtained by the DNS server according to the FQDN carried in the N record query request message; according to the S-GW or P-GW list and local rules returned by the DNS server, select an S-GW The GW or P-GW initiates an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW; initiates a mobility management process to the selected S-GW or P-GW, the The UE-related information includes: the UE's access point name (APN). 11. The MME according to claim 10, wherein the UE location information carried in the mobility management message received by the mobility management module is an eNodeB identifier or TAI of an area where the UE is located. 12. The MME according to claim 10, wherein the mobility management message received by the mobility management module is an attach message, or a tracking area update message, or a handover reselection message. 13. A DNS proxy server, characterized in that, the DNS proxy server is located in the LTE network of MME centralized deployment, and the DNS proxy server includes: Configuration module: save the IP address and geographical location information of the DNS server in each area; DNS query module: Receive the DNS query request message sent by the MME, the message carries the UE location information, and at the same time carries the UE-related information required to construct the FQDN, according to the UE location information, in the DNS server of each area saved by the configuration module In the IP address and geographic location information, find the IP address of the matching DNS server, construct the FQDN according to the UE-related information in the DNS query request message, and send an N record query request message to the matching DNS server, carrying the FQDN in the message, so that DNS The server obtains the corresponding S-GW or P-GW list according to the FQDN, and sends the S-GW or P-GW list to the MME; wherein, the DNS query request message is received by the MME from the UE After the mobility management message carrying the UE location information is sent to the DNS proxy server, the UE-related information includes: the UE's access point name APN. 14. A kind of LTE system that MME centrally deploys, it is characterized in that, this system comprises: UE: Send a mobility management message to the network side, which carries UE location information; MME: Save the correspondence between UE location information and the IP address of the DNS server in the area where the UE is located; when receiving a mobility management message from the UE, according to the UE location information in the message, the stored UE location information and In the corresponding relationship of the DNS server IP address, find the IP address of the matching DNS server, construct the FQDN according to the relevant information of the UE, and send the N record query request message to the matching DNS server, the message carries the FQDN, according to the DNS server returned S-GW or P-GW list and local rules, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the IP address of the selected S-GW or P-GW, according to DNS The IP address of the selected S-GW or P-GW returned by the server initiates a mobility management process to the selected S-GW or P-GW, and the UE-related information includes: the UE's access point name APN. 15. The LTE system according to claim 14, wherein the UE location information is an eNodeB identifier or TAI of an area where the UE is located. 16. The LTE system according to claim 14, wherein the mobility management message is an attach message, or a tracking area update message, or a handover reselection message. 17. A kind of LTE system that MME centrally deploys, it is characterized in that, this system comprises: UE: Send a mobility management message to the network side, which carries UE location information; MME: Receive the mobility management message sent by the UE, which carries the UE location information, and sends a DNS query request message to the DNS proxy server, which carries the UE location information and UE-related information required to construct the FQDN; receives the DNS server According to the S-GW or P-GW list sent by the S-GW or P-GW list and local rules, select an S-GW or P-GW, and initiate an A record query request to the DNS server to obtain the selected The IP address of the S-GW or P-GW, according to the IP address of the selected S-GW or P-GW returned by the DNS server, initiates a mobility management process to the selected S-GW or P-GW, said UE-related information includes: UE's access point name APN; DNS proxy server: save the IP address and geographic location information of the DNS server in each area; receive the DNS query request message, and according to the UE location information in the message, save the IP address and geographic location information of the DNS server in each area , the IP address of the matching DNS server is found, the FQDN is constructed according to the UE-related information in the DNS query request message, and the N record query request message is sent to the matching DNS server, and the FQDN is carried in the message. 18. The LTE system according to claim 17, wherein the UE location information is an eNodeB identifier or TAI of an area where the UE is located. 19. The LTE system according to claim 17, wherein the mobility management message is an attach message, or a tracking area update message, or a handover reselection message.