CN103096292A

CN103096292A - Network capacity identifying method and system

Info

Publication number: CN103096292A
Application number: CN2011103458906A
Authority: CN
Inventors: 周星月; 梁爽; 朱春晖
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2011-11-04
Filing date: 2011-11-04
Publication date: 2013-05-08

Abstract

The invention discloses a network capacity identifying method and a system. In the 3rd generation partnership project (3GPP), after a plurality of packet data network (PDN) connections can be built (MUPSAP) under the conditions that a servicing gateway (S-GW) acquires the own of the S-GW and / or a packet data network gateway (PDN GW) don't support the same access point name (APN), the information which is carried with the own information and / or the information of the PDN GW can be sent to a mobile management element (MME), wherein the information of the PDN GW is used for not supporting the information of the MUPSAP. After the MME acquires the S-GW and / or the information of the PDN GW, reason value which corresponds to the information is filled in a non-access layer of network access server (NAS) information and the reason value is sent to a user experience device (UE), wherein the information of PDN GW is used for not supporting the information of the MUPSAP. The invention further discloses a network capacity identifying system. When the S-GW and / or the PDN GW is used for not supporting the MUPSAP, the MME is able to installing the reason values and the reason values is not permitted that the plurality of the PDN connections are built below the single APN.

Description

Method and system for identifying network capability

Technical Field

The present invention relates to mobile communication technologies, and in particular, to a method and a system for identifying network capabilities.

Background

As shown in fig. 1, the Evolved Packet System (EPS) of the third Generation Partnership Project (3GPP, 3rd Generation Partnership Project) is composed of an Evolved Universal mobile telecommunications System Terrestrial Radio Access Network (E-UTRAN, Evolved Universal mobile telecommunications Network Access), a mobile Management unit (MME, Mobility Management Entity), (S-GW, Serving Gateway), a Packet Data Network Gateway (P-GW or PDN GW, Packet Data Network Gateway), a Home Subscriber Server (HSS, Home Subscriber Server), a Policy and Charging Rules Function (PCRF, Policy and Charging functions Function) Entity, a Serving GPRS SUPPORT NODE (SGSN, Serving GPRS NODE), a UMTS Terrestrial Radio Access Network (UMTS ), a Radio Network Access Network (GPRS) and gtcharging Function (gtgtjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj.

The MME is responsible for the related work of control planes such as mobility management, the processing of non-access stratum signaling, the management of user mobility management context and the like; the S-GW is an access gateway device connected with a base station of the E-UTRAN, forwards data between the E-UTRAN and the PDN GW, and is responsible for caching paging waiting data; the PDN GW is a border gateway between the EPS and a Packet Data Network (PDN), and is responsible for accessing the PDN and forwarding Data between the EPS and the PDN; the PCRF is a policy and charging rule function entity, and is connected to an operator network Protocol (IP, Internet Protocol) Service network through a receiving interface Rx to acquire Service information, and is connected to a gateway device in the network through a Gx/Gxa/Gxc interface to initiate establishment of an IP bearer, ensure quality of Service (QoS) of Service data, and perform charging control.

The EPS supports the intercommunication with the non-3GPP network and realizes the intercommunication with the non-3GPP network through an S2a/S2b/S2c interface. Non-3GPP networks include trusted non-3GPP networks and untrusted non-3GPP networks. The IP access of the trusted non-3GPP network can be directly interfaced with the PDN GW through S2 a; an IP access of an untrusted non-3GPP network needs to be connected to a P-GW through an Evolved data gateway (ePDG), and an interface between the ePDG and the PDN GW is S2 b.

If the EPS system supports Policy and Charging Control (PCC), the PCRF makes Policy and Charging rules, and the PCRF is connected to the operator IP service network through the receiving interface Rx to obtain service information, and in addition, the PCRF is connected to a gateway device in the network through a Gx/Gxa/Gxc interface to initiate the establishment of an IP bearer, ensure QoS of service data, and perform Charging Control. The Policy and Charging Enforcement Function (PCEF) is located in the PDN GW, and the PCRF exchanges information with the PDN GW through a Gx interface. When the interface between the PDN GW and the S-GW is based on Proxy Mobile IP (PMIP), a Bearer Binding and Event Report Function (BBERF) exists in the S-GW, and information is exchanged between the S-GW and the PCRF through a Gxc interface. When the trusted non-3GPP network is accessed, the BBERF also resides in the trusted non-3GPP access gateway, and information is exchanged between the trusted non-3GPP network access gateway and the PCRF through a Gxa interface. When the UE roams, the interfaces of the home PCRF and the visited PCRF are S9 interfaces, and meanwhile, an Application Function (AF) that provides a service for the UE is located in the service network, and sends service information for generating the PCC policy to the PCRF through the Rx interface.

In the current technology, the protocols adopted in the PCC architecture are Diameter application protocols developed on the basis of Diameter base protocols (Diameter base protocols), for example, application protocols applied to a Gx interface, application protocols applied to an Rx interface, application protocols applied to a Gxx interface (including Gxa and Gxc interfaces), application protocols applied to a roaming interface S9, and the like. Messages, commands, and Attribute Value Pairs (AVPs), etc. for the PCC are defined in these application protocols. The Diameter sessions established with these protocols may become Gx, Gxx, Rx, and S9 sessions, respectively. And each PCC functional entity carries out policy charging control on the PDN connection established by the UE access network through the sessions.

The EPS system supports Multiple (Multiple) PDN access, i.e. the UE can access Multiple PDNs simultaneously through Multiple PDN GWs or one PDN GW, and the EPS supports that the UE can access the same PDN Multiple times simultaneously. In 3GPP, a corresponding PDN network can be found through an Access Point Name (APN). Therefore, it can be considered that the UE may access the same APN multiple times at the same time, that is, the UE may request to establish multiple PDN connections under the same APN. Performing the above functions requires both terminal and network support.

The Proxy Mobile IPv6 protocol (PMIPv6, Proxy Mobile IPv6) is a Mobile IP management protocol based on the network, PMIPv6 does not need UE to participate in any mobility management work, the network is responsible for UE mobility management, and the UE does not sense the influence of three-layer connection brought by the mobility. For a Mobile Node (MN), regardless of where the MN moves, the MN considers itself on the Home Link. As shown in fig. 2, the 3GPP includes the following network elements based on PMIPv6 network architecture and corresponding interface: HSS, 3GPP Access network, S-GW, PDN GW, trusted Non-3GPP IP Access network (Trustednon-3GPP IP Access), ePDG, 3GPP AAA server, and Untrusted Non-3GPP IP Access network (Untrusted Non-3GPP IP Access). Wherein, the key nodes and functions of PMIPv6 are as follows:

local Mobility Anchor (LMA, Local Mobility Anchor): managing a binding route of the MN for a home agent (HomeAgent) of the MN and a topology anchor point of a home address of the MN; PDNGW in 3GPP network provides LMA function, responsible for data forwarding between MN and packet data network;

mobile Access Gateway (MAG): the change of a network layer caused by mobile switching is shielded, and the proxy MN completes the work of binding and updating; in the 3GPP network architecture, the corresponding S-GW, trusted non-3GPP IP access network, ePDG provide MAG functionality.

Proxy mobility management is realized between the LMA and the MAG through a Proxy Binding Update message (PBU) and a Proxy Binding Acknowledgement message (PBA). The PBU is sent by the MAG to the LMA and the PBA is sent by the LMA to the MAG, both messages occurring in message pairs. MAG sends the binding relation between its own proxy address and home address of UE MN to LMA through PBU, LMA saves the corresponding relation so as to correctly route and forward the up and down going message of MN. The PBU is mainly used for binding update, binding period update and binding cancellation, and the corresponding LMA confirms the PBU request by sending a PBA message to the MAG.

The establishment of Multiple PDN connections (MUPSAP) to the Same name APN for PMIP-based Interfaces under the Same APN on the PMIP-based interface is an optional feature for the network, i.e. MAG and LMA may or may not support this feature. When UE is initially attached to a network, if a current MAG supports an MUPSAP (multi user access point), the MAG can contain a PDN Connection identification (Connection ID) in a PBU (packet data unit) message sent to an LMA (local area network) to distinguish different PDN connections under the same APN (access point), and if the LMA supports the MUPSAP, the LMA can contain the PDN Connection ID in the PBA and return the PDN Connection ID to the MAG after establishing binding; if the LMA does not support the MUPSAP, the LMA ignores the PDN Connection ID, and the returned PBA does not contain the PDN Connection ID. The MAG supporting the MUPSAP judges whether the LMA supports the MUPSAP or not by judging whether the PBA contains the PDN connection ID or not.

If the UE has already established PDN connection under one APN, another PDN connection under the same APN is initiated to the network, when MAG receives the request message, MAG records whether the current LMA supports MUPSAP or not, if not, the S-GW (MAG) where the MAG is located directly rejects the request. On a PMIP-base S5/S8 interface, an S-GW (MAG) sends a rejection message to an MME, and the MME sets a reason value corresponding to the rejection message and feeds the reason value back to the user equipment in a non-access stratum (NAS) message.

The above-described MUPSAP handling mechanism has two problems:

1. the prior art does not define the MUPSAP rejection cause value sent by the S-GW to the MME, which will cause that the MME cannot set the corresponding "multiple PDN connections under APN disallowed" cause value in the NAS message after receiving the rejection message.

2. Each time the process has to go to the S-GW to sense whether the LMA supports the MUPSAP, the signaling efficiency is low.

Disclosure of Invention

In view of the above, the main object of the present invention is to provide a method and a system for identifying network capability, where when an S-GW and/or a PDN GW does not support MUPSAP, an MME is capable of setting a cause value for not allowing multiple PDN connections under a corresponding single APN in a NAS message.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

the invention provides a network capability identification method, which comprises the following steps:

in a 3GPP network, after learning that the S-GW and/or the PDN GW do not support the MUPSAP, the S-GW carries information that the S-GW and/or the PDN GW do not support the MUPSAP in a message sent to an MME;

and after the MME obtains the information that the S-GW and/or the PDN GW do not support the MUPSAP, filling a reason value corresponding to the information in an NAS message and sending the information to the UE.

In the above solution, the message sent to MME carrying information that itself and/or the PDN GW does not support MUPSAP is: and after receiving another PDN connection request under the same APN sent by the UE, the S-GW carries a core network cause value which is not allowed by multi-PDN connection under a single APN in a rejection message sent to the MME.

In the above solution, the message sent to MME carrying information that itself and/or the PDN GW does not support MUPSAP is: and the S-GW comprises the information that the self and/or the PDN GW does not support the MUPSAP in the session establishment response message returned to the MME.

In the above solution, after the MME obtains the information that the S-GW and/or the PDN GW does not support the MUPSAP, the MME fills a cause value corresponding to the information in an NAS message and sends the message to the UE, where the cause value is:

and the MME fills the user side cause value which is not allowed by the multi-PDN connection under the single APN and corresponds to the cause value in the NAS message and sends the user side cause value to the UE according to the core network cause value which is not allowed by the multi-PDN connection under the single APN and is carried in the rejection message.

and the MME locally records the information that the S-GW and/or the PDN GW do not support the MUPSAP according to the information that the S-GW and/or the PDN GW do not support the MUPSAP contained in the session establishing response message, fills a user side reason value which is not allowed by multiple PDN connections under a single APN in the NAS message and sends the user side reason value to the UE when receiving another PDN connection request under the same APN sent by the UE, and rejects the connection request.

The invention provides a network capability identification system, which comprises: S-GW, MME and UE; wherein,

the S-GW is used for carrying the information that the self and/or the PDN GW does not support the MUPSAP in the message sent to the MME after the fact that the self and/or the PDN GW does not support the MUPSAP is known;

and the MME is used for filling a reason value corresponding to the information in the NAS message and sending the reason value to the UE after the information that the S-GW and/or the PDN GW do not support the MUPSAP is obtained.

In the foregoing scheme, the S-GW is specifically configured to, after receiving another PDN connection request under the same APN sent by the UE, carry a core network cause value that is not allowed for multiple PDN connections under a single APN in a reject message sent to the MME.

In the foregoing solution, the S-GW is specifically configured to include, in a session establishment response message returned to the MME, information that the self and/or the PDN GW does not support the MUPSAP.

In the foregoing scheme, the MME is specifically configured to fill, in the NAS message, a user side cause value that is not allowed for multiple PDN connections under a single APN and corresponds to the cause value according to the core network cause value that is not allowed for multiple PDN connections under the single APN and is carried in the reject message, and send the user side cause value to the UE.

In the above scheme, the MME is specifically configured to locally record information that the S-GW and/or the PDN GW does not support the MUPSAP according to that the session establishment response message includes information that the S-GW and/or the PDN GW does not support the MUPSAP, fill a user side cause value that multiple PDN connections are not allowed under a single APN in the NAS message and send the user side cause value to the UE when another PDN connection request under the same APN sent by the UE is received, and reject the connection request.

The invention provides a method and a system for identifying network capability.A S-GW carries information that the S-GW does not support the MUPSAP (multi user equipment access point) in a message sent to an MME (mobility management entity) after knowing that the S-GW and/or the PDN GW do not support the MUPSAP; after the MME obtains the information that the S-GW and/or the PDNGW do not support the MUPSAP, filling a reason value corresponding to the information in an NAS message and sending the information to the UE; thus, when the S-GW and/or the PDN GW do not support the MUPSAP, the MME can set a cause value of not allowing multiple PDN connections under a single APN in the NAS message; and the MME can directly reject another PDN connection request under the same APN sent by the UE by recording the information that the S-GW and/or the PDN GW do not support the MUPSAP.

Drawings

Fig. 1 is a schematic diagram of a 3GPP EPS network architecture in the prior art;

FIG. 2 is a schematic diagram of a 3GPP PMIPv 6-based network architecture in the prior art;

FIG. 3 is a flow chart illustrating a method for implementing network capability identification in accordance with the present invention;

FIG. 4 is a schematic diagram of a system for implementing network capability identification according to the present invention;

fig. 5 is a flowchart illustrating a method for implementing network capability identification according to an embodiment of the present invention;

fig. 6 is a flowchart illustrating a method for implementing network capability identification according to a second embodiment of the present invention.

Detailed Description

The basic idea of the invention is: in a 3GPP network, after learning that the S-GW and/or the PDN GW do not support the MUPSAP, the S-GW carries information that the S-GW and/or the PDN GW do not support the MUPSAP in a message sent to an MME; and after the MME obtains the information that the S-GW and/or the PDN GW do not support the MUPSAP, filling a reason value corresponding to the information in an NAS message and sending the information to the UE.

The invention is further described in detail below with reference to the figures and the specific embodiments.

The invention realizes a method for identifying network capability, as shown in fig. 3, the method comprises the following steps:

step 101: in a 3GPP network, after learning that the S-GW and/or the PDN GW do not support the MUPSAP, the S-GW carries information that the S-GW and/or the PDN GW do not support the MUPSAP in a message sent to an MME;

the message sent to the MME carries information that the S-GW itself and/or the PDN GW does not support MUPSAP, which may be that the S-GW carries a core network cause value that multiple PDN connections are not allowed under a single APN in a rejection message sent to the MME after receiving another PDN connection request under the same APN sent by the UE; or the S-GW sends a session establishing response message to the MME, wherein the session establishing response message contains information that the S-GW and/or the PDN GW do not support the MUPSAP;

specific examples are as follows: in a 3GPP network, MME sends a session establishment request message to S-GW, S-GW supporting MUPSAP sends PBU message to PDN GW, the PBU message contains PDNConnection ID, PDN GW receives the PBU message, PDN GW ignores PDN Connection ID in the PBU message because it does not support MUPSAP, PBU message containing no PDN Connection ID is sent to S-GW after a binding relationship is established; the S-GW acquires that the PDN GW does not support the MUPSAP according to the fact that the PBA message does not contain the PDNConnection ID, records the information that the PDN GW does not support the MUPSAP, returns a session establishment response message to the MME, and sends an attachment acceptance to the UE by the MME to complete the establishment of the initial attachment connection; after receiving another PDN connection request under the same APN sent by the UE, the S-GW carries, in a reject message sent to the MME, a core network cause value that is not allowed for multiple PDN connections under a single APN, where the core network cause value that is not allowed for multiple PDN connections under a single APN is as follows: # 55: multiple PDN connections for a seven APN not allowed;

or in a 3GPP network, MME sends a session establishment request message to S-GW, S-GW supporting MUPSAP sends PBU message to PDN GW, the PBU message contains PDNConnection ID, PDN GW receives the PBU message, PDN GW ignores PDN Connection ID in the PBU message because it does not support MUPSAP, PBU message is sent PBA message not containing PDN Connection ID to S-GW after a binding relation is established; the S-GW acquires that the PDN GW does not support the MUPSAP according to the fact that the PBA message does not contain the PDNConnection ID, records the information that the PDN GW does not support the MUPSAP, returns a session establishment response message to the MME, contains the information that the PDN GW does not support the MUPSAP in the session establishment response message, locally records the information that the PDN GW does not support the MUPSAP by the MME, sends an attachment acceptance message to the UE, and completes the attachment process; the information that the PDN GW does not support MUPSAP may be implemented by defining a flag, e.g. 00 indicates that the PDN GW does not support MUPSAP.

Further, when the S-GW supports MUPSAP, the session establishment response message may further include information that the S-GW supports MUPSAP, in addition to information that the PDN GW does not support MUPSAP.

Step 102: and after the MME obtains the information that the S-GW and/or the PDN GW do not support the MUPSAP, filling a reason value corresponding to the information in an NAS message and sending the information to the UE.

Specifically, the MME fills, in the NAS message, a cause value of a user side, which is not allowed for multi-PDN connection under a single APN, corresponding to the cause value, according to a core network cause value, which is not allowed for multi-PDN connection under the single APN, carried in the reject message, and sends the user side cause value, which is not allowed for multi-PDN connection under the single APN, corresponding to the cause value, to the UE, where the cause value of the user side, which is not allowed for multi-PDN connection under the: # 100: multiple PDN connections for a givenAPN not allowed; or,

In order to implement the above method, in the 3GPP network, the present invention further provides a system for identifying network capabilities, as shown in fig. 4, the system includes: S-GW 11, MME 12, UE 13; wherein,

the S-GW 11 is configured to, after knowing that the itself and/or the PDN GW14 do not support the MUPSAP, carry information that the itself and/or the PDN GW14 do not support the MUPSAP in a message sent to the MME 12;

MME 12, is used for after obtaining the information that said S-GW 11 and or PDN GW14 does not support MUPSAP, fill in the reason value corresponding to said information in NAS message and send to UE 13;

the system further comprises a PDN GW14, which is used for neglecting the PDN Connection ID in the PBU message when the system does not support the MUPSAP, and sending the PBA message without the PDN Connection ID to the S-GW 11 after establishing the binding relationship;

the S-GW 11 is specifically configured to, after receiving another PDN connection request under the same APN sent by the UE 13, carry a core network cause value that multiple PDN connections are not allowed under a single APN in a reject message sent to the MME 12;

or, the S-GW 11 is specifically configured to include, in the session establishment response message returned to the MME 12, information that the self and/or the PDN GW14 do not support the MUPSAP;

the MME 12 is specifically configured to fill, in the NAS message, a user side cause value that is not allowed for multiple PDN connections under a single APN and corresponds to the cause value according to a core network cause value that is not allowed for multiple PDN connections under the single APN and is carried in the reject message, and send the user side cause value to the UE 13;

or, the MME 12 is specifically configured to locally record information that the S-GW 11 and/or the PDN GW14 do not support the MUPSAP according to the information that the S-GW 11 and/or the PDN GW14 do not support the MUPSAP included in the session establishment response message, and when another PDN connection request under the same APN sent by the UE 13 is received, fill a user side cause value that multiple PDN connections are not allowed under the single APN in the NAS message, send the user side cause value to the UE 13, and reject the connection request.

The following detailed description of the implementation and principles of the method of the present invention is provided in connection with specific embodiments.

Example one

Fig. 5 is the UE initially attached to the EPS network, establishing a PDN connection using PMIPv6 mobility management protocol, where the S-GW supports MUPSAP and the PDN GW does not support MUPSAP. After the initial attachment is finished, UE initiates a new PDN connection request under the same APN to the network again, by using the method of the invention, S-GW fills the core network cause value which is not allowed by multiple PDN connections under single APN in the rejection message sent to MME, MME fills the user end cause value which is not allowed by multiple PDN connections under single APN and is corresponding to the cause value in NAS message according to the cause value, and sends the user end cause value to UE. The embodiment specifically comprises the following steps:

step 201: the UE sends an attachment request message to the MME;

in this step, if the attach request message has no integrity protection or the integrity protection fails, the MME executes an authentication process of the user.

Step 202: MME sends a session establishment request message to S-GW;

step 203: the method comprises the steps that an S-GW supporting a MUPSAP sends a PBU message to a PDN GW, the PBU message comprises a PDN Connection ID, the PDN GW receives the PBU message, and the PDN GW ignores the PDN Connection ID in the PBU message and sends the PBA message not comprising the PDN Connection ID to the S-GW after establishing a binding relationship because the PDN GW does not support the MUPSAP;

step 204: the S-GW knows that the PDN GW does not support the MUPSAP according to the fact that the PBA message does not contain the PDN Connection ID, records the information that the PDN GW does not support the MUPSAP, returns a session establishment response message to the MME, and the MME sends an attachment acceptance to the UE to complete initial attachment Connection establishment;

step 205: UE sends another PDN connection request under the same APN to the network;

step 206: the S-GW carries a core network cause value which is not allowed by multi-PDN connection under a single APN in a rejection message sent to the MME;

step 207: and the MME fills the user side cause value which is not allowed to be connected with the multiple PDNs under the single APN and corresponds to the cause value in the NAS message according to the core network cause value which is not allowed to be connected with the multiple PDNs under the single APN and carried in the rejection message, and sends the user side cause value to the UE.

Example two

Fig. 6 is the UE initially attached to the EPS network, establishing a PDN connection using PMIPv6 mobility management protocol, where the S-GW supports MUPSAP and the PDN GW does not support MUPSAP. After the initial attachment is completed, the UE initiates a new PDN connection request under the same APN to the network. By using the method of the invention, the S-GW informs the MME PDN GW that the MUPSAP is not supported in the initial attachment establishment process. The embodiment specifically comprises the following steps:

step 301: the UE sends an attachment request message to the MME;

Step 302: MME sends a session establishment request message to S-GW;

step 303: the method comprises the steps that an S-GW supporting a MUPSAP sends a PBU message to a PDN GW, the PBU message comprises a PDN Connection ID, the PDN GW receives the PBU message, and the PDN GW ignores the PDN Connection ID in the PBU message and sends the PBA message not comprising the PDN Connection ID to the S-GW after establishing a binding relationship because the PDN GW does not support the MUPSAP;

step 304: the S-GW knows that the PDN GW does not support the MUPSAP according to the fact that the PBA message does not contain the PDN Connection ID, and records the information that the PDN GW does not support the MUPSAP;

step 305: S-GW returns a session establishment response message to MME, and MME sends attachment acceptance to UE to complete initial attachment connection establishment;

step 306: the service gateway sends a session establishing response message to the MME, wherein the session establishing response message contains information that the PDN GW does not support the MUPSAP, and the MME locally records the information that the PDN GW does not support the MUPSAP;

further, the session establishment response message also contains information that the S-GW supports MUPSAP.

Step 307: the MME sends an attachment acceptance message to the UE, and the attachment process is completed;

step 308: UE sends another PDN connection request under the same APN to the network;

step 309: and the MME fills a user terminal cause value which is not allowed by multi-PDN connection under a single APN in the NAS message according to the information that the PDN GW does not support the MUPSAP in the session establishing response message, and sends the user terminal cause value to the UE, and rejects the connection request.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.

Claims

1. A method for network capability identification, the method comprising:

in a third generation partnership project (3GPP) network, after a serving gateway (S-GW) establishes a plurality of Packet Data Network (PDN) connections (MUPSAP) under the condition that the serving gateway (S-GW) and/or a packet data network gateway (PDN GW) do not support the same Access Point Name (APN), carrying information that the serving gateway (S-GW) and/or the PDN GW do not support the MUPSAP in a message sent to a mobile management unit (MME);

and after the MME obtains the information that the S-GW and/or the PDN GW do not support the MUPSAP, filling a reason value corresponding to the information in a non-access stratum (NAS) message and sending the reason value to the UE.

2. The method of claim 1, wherein the message sent to MME carrying information that itself and/or the PDN GW does not support MUPSAP is: and after receiving another PDN connection request under the same APN sent by the UE, the S-GW carries a core network cause value which is not allowed by multi-PDN connection under a single APN in a rejection message sent to the MME.

3. The method of claim 1, wherein the message sent to MME carrying information that itself and/or the PDN GW does not support MUPSAP is: and the S-GW comprises the information that the self and/or the PDN GW does not support the MUPSAP in the session establishment response message returned to the MME.

4. The method of claim 2, wherein after the MME obtains the information that the S-GW and/or PDN GW does not support MUPSAP, filling a cause value corresponding to the information in an NAS message, and sending the cause value to the UE, where the cause value is:

5. The method of claim 3, wherein after the MME obtains the information that the S-GW and/or the PDN GW do not support the MUPSAP, filling a cause value corresponding to the information in an NAS message and sending the message to the UE is:

6. A system for network capability identification, the system comprising: S-GW, MME and UE; wherein,

7. The system of claim 6, wherein the S-GW is specifically configured to, after receiving another PDN connection request under the same APN sent by the UE, carry a core network cause value disallowed for multiple PDN connections under a single APN in a reject message sent to the MME.

8. The system according to claim 6, wherein said S-GW is specifically configured to include information that itself and/or the PDN GW does not support the MUPSAP in the setup session response message returned to the MME.

9. The system of claim 7, wherein the MME is specifically configured to fill, in the NAS message, a user-side cause value, corresponding to the cause value, of the multiple PDN connection disallowance under a single APN, and send the user-side cause value to the UE, according to a core network cause value, which is not allowed for the multiple PDN connection under the single APN, and is carried in the reject message.

10. The system of claim 8, wherein the MME is specifically configured to locally record information that the S-GW and/or the PDN GW does not support the MUPSAP according to that the session establishment response message includes information that the S-GW and/or the PDN GW does not support the MUPSAP, and when another PDN connection request under the same APN sent by the UE is received, fill a user side cause value that multiple PDN connections are not allowed under a single APN in the NAS message, send the UE to the MME, and reject the connection request.