MX2012001252A - Message-sending method and serving gprs support node. - Google Patents

Abstract

A message-sending method and serving GPRS support node (SGSN) are disclosed. The method includes the following steps: When the SGSN connected with user equipment (UE) hands over from the first SGSN to the second SGSN, the first SGSN sends the second SGSN a message with UE context information including the type of packet data network (PDN) gateway which the UE connects with. The new SGSN can get the type of PDN gateway and then select the type of interface in use correctly according to the type of PDN gateway.

Description

Method of Sending Messages and GPRS Service Support Node Field of the Invention The present invention relates to the field of communications and in particular to a method of sending messages and a GPRS service support node.

Background of the Invention Currently, the standardization work team of the Association Project of Third Generation (cited as 3GPP) focuses on the evolution study of the Packet Switching Core Network (referred to as the PS core network) and the Radio Access Network of the Universal Mobile Telecommunications System (cited as UTRAN), with in order to allow the evolved PS core network (cited as EPC) to provide a higher transmission speed and a shorter transmission delay and support mobility management between the evolved UTRAN (evolved UTRAN, cited as E-UTRAN) , the Global System for Improved Data Rates of Mobile Communications for the radio access network for the Evolution of GSM (cited as GERAN), UTRAN, the Wireless Local Area Network (referred to as WLAN) and other unrelated access networks with 3GPP. The evolved system of mobile communications is known as Evolved Packet System (cited as EPS). Figure 1 is a schematic diagram of network architecture according to the relevant technology. The entities shown in Figure 1 are described in detail below.

The Mobile Station (cited as MS, also as a mobile terminal) / Equipment User (cited as UE) 101, which has the ability to access two wireless networks, is known as a dual-mode terminal. In the following description, the l UE is a dual-mode terminal capable of accessing the UMTS / GSM and EPS networks and MS / UE is described uniformly as UE.

GERAN / UTRAN 102 is a radio access network of the traditional GSM / UMTS network.

The GPRS Service Support Node (General Packet Service via Radio) (cited as SGSN) 103 is a network control element of the GPRS network, which mainly functions to register the location information of the UE and perform the sending and the reception of mobile data packets between the UE and the GPRS Access Portal Support Node (cited as GGSN).

The service access portal (cited as S-GW) 104 is an entity in the user plane and is responsible for the processing of data routing in the user plane.

The Packet Data Network Access Portal (cited as PDN GW or P-GW) 105 is responsible for the functions of the Packet Data Network access portal (referred to as PDN) to which the UE has access .

The P-GW and the S-GW can be provided in either a single physical entity as shown in Figure 1, or in different physical entities.

The Support Node of the GPRS Access Portal (General Packet Service via Radio) (cited as GGSN) 106 supports the end routing function of the GPRS network. The GGSN is responsible for routing and sending data from the GPRS network and protecting the integrity of the GPRS network data through the firewall and filtering functions. The GGSN also has the accounting function.

The PGW has all the functions of the GGSN. The GGSN can be considered as a subfunction of the PGW located jointly in the PGW. In this way, the SGSN can connect directly to the PGW, using a Gn / Gp interface.

The Subscriber Local Server (cited as HSS) / Record of Origin Positions (cited as HLR) 107 is a primary user database supporting calls / sessions.

The IP Multimedia Subsystem (Internet Protocol) of the Core Network (cited as IMS) is an IP-based network architecture proposed by 3GPP. It builds an open and flexible service environment, which supports multimedia applications and provides abundant multimedia services to users. The IMS is an IP-based telecommunications network architecture, without any relation to access technology, and can provide services to mobile cellular networks such as GSM and the Universal Mobile Telecommunications System (referred to as UMTS), in addition of packet access networks such as EPS, General Packet Service via Radio (referred to as GPRS) and Wireless Local Area Network (referred to as WLAN).

After the UE is connected to the network, an Access Point Name (referred to as APN) will be established and the SGSN will determine whether a PDN connection is established to the GGSN or to the PGW for the user according to the capacity information. verified by the UE and the local configuration information. Once the PDN connection is established, the GGSN or the PGW serves as an anchor for the PDN connection by linking to the external PDN network. That is, for the PDN connection, the GGSN or the PGW will not change, unless the PDN connection is released.

If the location of the UE has changed and a routing area has changed, the UE will initiate the update of the location of the routing area. Figure 2 is a flow diagram of the updating of the UE routing according to the relevant technology. As shown in Figure 2, the flow chart includes the following steps.

Step 201, the UE initiates a routing area update request and the request is sent to a new SGSN through the BSC / SRNS and the request bears a valid Mobile Subscriber Temporary Identity (quoted as P-TMSI) and the type of routing area update.

Steps 202-203, the new SGSN requests background information from the previous SGSN UE according to the P-TMSI.

Step 204, for security purposes, the authentication and encryption process is performed.

This step is optional, however, if there is no UE context information on the network, the step must be performed.

Step 205, after receiving the context information of the UE, the new SGSN returns a context request recognition message to the previous SGSN.

Steps 206-207, the new SGSN sends a PDP update request to the GGSN, where the PDP update request carries TEID and IP address of the new SGSN and the GGSN stores the information and returns a PDP update response to the SGSN new.

Step 208, the new SGSN and the HSS send a location update carrying a new SGSN identifier and the HSS stores the identifier.

Steps 209-210, the HSS sends a location cancellation to the previous SGSN and the HSS will no longer store the previous SGSN identifier after the previous SGSN returns a cancellation recognition to the HSS.

Steps 211-212, the HSS inserts subscriber data into the new SGSN.

Step 213, the HSS returns a location update recognition to the new SGSN.

Step 214, the new SGSN confirms that the UE is valid in the current routing area and sends an update acceptance message from the routing area to the UE carrying the P-TMSI reassigned to the UE.

Step 215, the UE returns an update completion message from the routing area to the SGSN to confirm that the P-TMSI is valid.

For step 206 and step 207 in block diagram A of Figure 2, assume that the new SGSN is connected to the GGSN using a Gn / Gp interface. Figure 3 is a schematic flow diagram of the SGSN employing an S4 interface according to the relevant technology. If the GGSN serves as a functional module located jointly of the PGW, as shown in Figure 3, the update flow of a holder between the SGSN and the PGW includes the following steps.

Step 301, the SGSN sends the SGW a session creation request carrying TEID and IP address of the PGW, TEID and SGSN IP address, holder context information and user identifier information.

Step 302, the SGW finds the PGW according to the information provided by the SGSN and sends the PGW a request for modification of the holder including TEID and SGW address and user identifier information.

Step 303, the PGW returns the owner modification response including TEID and PGW address.

Step 304, the SGW returns the session creation response carrying TEID and S-GW address.

As mentioned before, since the GGSN previously serves as a functional unit located together with the PGW, the new SGSN can not only connect to the GGSN through a Gn / Gp interface, but can also be connected, through the SGW, to the GGSN located jointly in the PGW. However, when the EPC provides some new network characteristics, for the SGSN which supports both the Gn / Gp interface and the S4 interface, an effective selection mechanism is required such that the SGSN can select network elements in accordance with your situations Description of the invention The present invention is provided in view of the lack of a selection mechanism for the SGSN to select the Gn / Gp interface or the S4 interface in the relevant technology. In this manner, the present invention is primarily intended to provide a method of sending messages based on an SGSN to solve at least one of the above problems.

In order to achieve the above objective, according to one aspect of the present invention, a method of sending messages is provided.

The method of sending messages in accordance with the present invention encompasses: when the SGSN, to which the user equipment is connected, changes from a first SGSN to a second SGSN, the first SGSN that sends a message to the second SGSN carrying information of context of the user equipment, wherein the context information includes the type of access portal of the packet data network to which the user equipment is connected.

Preferably, after the first SGSN sends the message to the second SGSN, the method also encompasses: the second SGSN receiving the message and acquiring from the message the type of access portal of the packet data network to which the computer The user is connected and determining, according to the type of access portal, the type of an interface that is used by the second SGSN to connect the access portal of the packet data network.

Preferably, the second SGSN acquiring from the message the type of access portal of the packet data network to which the user equipment is connected comprises: the second SGSN acquiring the type of access portal of the fully qualified domain name of the access portal included in the message, where when the message includes the fully qualified domain name of a combined access portal, the type of access portal acquired is an access portal of the PGW data network; When the message does not include the fully qualified domain name of the combined access portal, the type of access portal acquired is the GPRS access portal support node GGSN.

Preferably, the second SGSN determining, according to the type of portal of access, the type of an interface selected by the second SGSN covers: in the case that the access portal type is the access gateway of the PGW packet data network, determining that the connection to the network access portal of packet data is through an interface of type S4; in the case where the type of access portal is the GPRS access portal support node GGSN, determining that the connection to the access portal of the packet data network is through a Gn / Gp type interface.

Preferably, before the first SGSN sends the message to the second SGSN, the method further encompasses: the first SGSN determining the type of access portal and stores the type of access portal in the context information of the user equipment.

Preferably, the first SGSN determining the type of access portal includes: the first SGSN determining the type of access portal according to the information previously configured locally; the first SGSN determining the type of access portal according to the information provided by the user equipment and / or the subscription information.

In order to achieve the above objective, according to another aspect of the present invention, an SGSN is provided.

The SGSN according to the present invention encompasses: a sending module adapted to send, when the user equipment initiates a GPRS service support node exchange SGSN, a message carrying context information of the user equipment to an SGSN of target, wherein the context information includes the type of access portal of the packet data network to which the user equipment is connected.

Preferably, the SGSN further comprises: a first determination module adapted to determine a type of access portal; and a storage module adapted to store the type of access portal in the context information of the user equipment.

Preferably, the first determination module comprises: a first determination sub-module adapted to determine a type of access portal according to the information previously configured locally; a second determination submodule adapted to determine the type of access portal according to the information provided by the user equipment and / or the subscription information.

Preferably, the SGSN further comprises: a reception module adapted to receive, when the user equipment initiates an SGSN exchange, a message from a source SGSN, wherein the message carries the type of access portal of the network of packet data to which the user equipment is connected; an acquisition module adapted to acquire the type of message access portal; and a second determination module adapted to determine, in accordance with the type of access portal, the type of an interface which is used by the SGSN to connect the access portal of the packet data network.

Preferably, the acquisition module consists of: a first acquisition submodule adapted to acquire, when the message includes the fully qualified domain name of a combined access portal, the type of access portal that will be PGW; and a second acquisition submodule to acquire, when the message does not include the fully qualified domain name of the combined access portal, the type of access portal that will be GGSN.

Preferably, the second determination module comprises: a first connection sub-module adapted to connect to the access portal of the packet data network through an interface of type S4, in case the type of access portal is PGW; and a second connection submodule adapted to connect to the access portal of the packet data network through a Gn / Gp type interface, in case the access portal type is GGSN.

Through the present invention, the message sent from the previous SGSN to the new SGSN carries the type of access portal of the packet data network PDN to which the user equipment is connected. Solves the problem of the lack of a mechanism in technology relevant to the new SGSN to select a Gn / Gp interface or an S4 interface and therefore achieves the effects that the new SGSN can acquire the type of access portal of the network of data by PDN packets and correctly select the type of an interface according to the type of access portal.

Brief Description of the Drawings The drawings herein are used to provide a further understanding of the present invention and form part of the specification. The embodiments of the present invention and their description are used to explain the present invention instead of unduly limiting the present invention. In the attached drawings: Figure 1 is a schematic diagram of the network architecture according to the relevant technology; Figure 2 is a flow chart of a routing update of the UE according to the relevant technology; Figure 3 is a schematic flow chart of the SGSN using an S4 interface according to the relevant technology; Figure 4 is a flow chart of the method of sending messages according to an embodiment of the present invention; Figure 5 is a flow diagram of the SGSN selecting a network element in the update process of the UE routing area according to an embodiment of the present invention; Figure 6 is a flow diagram of the SGSN in the process of alternating the connection state of the UE according to an embodiment of the present invention; Figure 7 is a flowchart of operations after the SGSN determines that an interface S4 is used in accordance with an embodiment of the present invention; Y Figure 8 is a structural block diagram of the SGSN according to an embodiment of the present invention.

Detailed Description of the Preferred Embodiments It will be explained that the embodiments of the present invention and their characteristics can be combined with each other in the absence of any conflict. The present invention is described in detail as follows with reference to the drawings and in conjunction with the embodiments. In the following embodiments, the steps shown or described in the flow diagrams in the drawings may be performed in an order that is different from the order described herein.

Realizations of the Method According to an embodiment of the present invention, a method of sending messages is provided. The method is used when the SGSN undergoes changes. The method is a scheme to perform the routing selection when the SGSN undergoes changes. Figure 4 is a flow chart of the method of sending messages according to an embodiment of the present invention. As shown in Figure 4, the method encompasses the steps from step S402 to step S404.

Step S402, an SGSN, to which the user equipment is connected, alternates a first SGSN (previous SGSN) to a second SGSN (new SGSN).

Step S404, the first SGSN sends to the second SGSN a message carrying context information of the user equipment, wherein the context information includes the type of access portal of the PDN packet data network to which the user equipment Are you connected. That is, during the process of sending the context information of the UE, the new SGSN is notified of the type of access portal chosen by the SGSN in the connection of the PDN. You can see the type of access portal through an extended parameter. For example, the type of access portal can be determined by the Fully Qualified Domain Name (quoted as FQDN) of the selected access portal. When the context information includes the FQDN of a combined access portal (GGSN located jointly in PGW), the access portal is considered as GGSN located together in PGW and if the context information does not include the FQDN of the combined access portal ( GGSN is located jointly in PGW), the access portal is considered as individual GGSN.

After step S404, the second SGSN receives the message and acquires the type of access portal of the message and determines, according to the type of access portal, the type of an interface which is used by the second SGSN to connect the access portal of the PDN. The type of interface includes S4 and Gn / Gp. The new SGSN determines, according to the information, whether to use an S4 interface to connect the PGW through the SGW, or to connect the GGSN through a Gn / Gp interface.

Prior to step S402, the first SGSN determines the type of access portal and stores the type of access portal in the context information of the user equipment. That is, when an APN connection is established for the UE, the previous SGSN registers the type of access portal of the packet data network selected by the SGSN., whether the GGSN is an independent node or a functional entity located jointly of the PGW. You can see the type of access portal through an extended parameter. For example, the type of access portal can be determined by the FQDN of the selected access portal. When the context information includes the FQDN of a combined access portal (the GGSN is located jointly in PGW), the access portal is considered as GGSN and is located together in PGW and if the context information does not include the FQDN of the portal of combined access (the GGSN is located jointly in PGW), the access portal is considered as individual GGSN. A dynamic method and a static method can be used to determine the type of the interface. The static method is where the first SGSN determines the type of access portal according to the information previously configured locally; and the dynamic method is where the first SGSN determines the type of access portal according to the information provided by the user equipment and / or subscription information. The two methods are described below in detail.

If the static configuration method is used, then the SGSN statically configures the type of the access portal that can be selected by the connection of the PDN that the UE can establish; and at the same time, the SGSN also needs to register the type of the selected access portal in the context information of the UE.

If the dynamic selection method is used, then the SGSN selects a GGSN through the DNS search according to the information provided by the UE and / or the subscription information and the SGSN registers the type of the selected access portal in the context information of the UE.

The implementation process of the embodiments of the present invention is described in detail below in conjunction with examples.

Figure 5 is a flow diagram of the SGSN selecting a network element in the update process of the routing area of the UE according to an embodiment of the present invention. As shown in Figure 5, the flow includes the following steps.

Step 501, the UE initiates an update request of the routing area and the request is sent to a new SGSN through the BSC / SRNS, where the request carries a valid P-TMSI and the type of update of the routing area.

Step 502, the new SGSN requests background information from the previous SGSN UE according to the P-TMSI.

Step 503, the UE context information returned by the previous SGSN to the new SGSN contains the type of the access portal selected by the UE PDN connection.

Step 504, for security purposes, the authentication and encryption process is performed.

The step is optional, however, if there is no UE context information in the network, the step must be performed.

Step 505, after receiving the UE context, the new SGSN returns a context request recognition message to the previous SGSN.

Step 506, the new SGSN selects an appropriate network element according to the context information of the UE returned by the previous SGSN.

If the GGSN is an independently used network element, the new SGSN is directly connected to the GGSN using a Gn / Gp interface. The specific flow is as shown in block diagram A of Figure 5.

If the GGSN is a functional entity located jointly in the PGW, the new SGSN is connected to the PGW through the SGW using an S4 interface. The specific flow is as shown in Figure 3 which is the related technique and no detailed description is repeated in the present.

Further, if the SGSN employs an S4 interface, the SGSN needs to perform the PDP context mapping for the EPS holder and no detailed description is provided herein.

Steps 507-508, the new SGSN sends a PDP update request to the GGSN, where the PDP update request carries TEID and the new SGSN's IP address; and the GGSN stores the information and returns a PDP update response to the new SGSN.

Step 509, the new SGSN and the HSS send a location update carrying an identifier of the new SGSN and the HSS stores the identifier.

Steps 510-511, the HSS sends a location cancellation to the previous SGSN and the HSS will no longer store the previous SGSN identifier, after the previous SGSN returns an acknowledgment of location cancellation to the HSS.

Steps 512-513, the HSS inserts subscriber data into the new SGSN.

Step 514, the HSS returns a location update response to the new SGSN.

Step 515, the new SGSN confirms that the UE is valid in the current routing area and sends an update acceptance message from the routing area to the UE carrying the P-TMSI reassigned to the UE.

Step 516, the UE returns an update realization message from the routing area to the SGSN to confirm the validity of the P-TMSI.

Figure 6 is a flow chart of the SGSN in the process of alternating the connection state of the UE according to an embodiment of the present invention. As shown in Figure 6, the flow includes the following steps.

Step 601, the above RNC determines, according to the information reported by the UE, that an alternation flow has to be performed.

Step 602, the previous RNC sends to the previous SGSN a relocation of required SRNS carrying a cause of relocation, identifiers of a source end and a destination end and a container transparently sent by the previous RNC to the new RNC through a core network .

Step 603, the previous SGSN sends a relocation send request to the new SGSN carrying the context information of the UE, where the context information of the UE includes the type of the access portal selected by the UE PDN connection.

Step 604, the new SGSN selects an appropriate network element according to the UE context information returned by the previous SGSN.

If the GGSN is an independently used network element, the new SGSN is directly connected to the GGSN using a Gn / Gp interface. The flow in block diagram B of Figure 6 need not be done in the present.

If the GGSN is a functional entity located jointly in the PGW, the new SGSN is connected to the PGW through the SGW using an S4 interface. Steps 605-606 need to be done in the present.

Further, if the SGSN employs an S4 interface, the SGSN needs to perform the PDP context mapping for the EPS holder and no detailed description is provided herein.

Step 605, the SGSN sends the SGW a session creation request carrying TEID and IP address of the PGW, TEID and SGSN IP address, holder context information and user identifier information.

Step 606, the SGW returns the session creation response carrying TEID and S-GW address.

Step 607, the new SGSN sends a relocation request to the new RNC carrying a UE identifier, a holder that has to be established and a container transparently sent by the previous RNC to the new RNC through a core network.

Step 608, a radio holder for the UE is established between the new SGSN and the new RNC.

Step 609, the new RNC returns a reconnaissance request acknowledgment to the new SGSN.

Step 610, the new SGSN sends a relocation submission response to the previous SGSN.

Step 611, the previous SGSN sends a relocation command to the previous RNC to notify the previous RNC that it begins to toggle.

Step 612, the previous RNC sends the new RNC an SRNS relocation commitment carrying the SRNS context of the UE.

Steps 613-614, the new RNC interacts with the UE for mobility information of RAN.

Step 615, the new RNC sends the SRNS relocation termination to the new SGSN, notifying that the wireless alternation has been completed.

Steps 616-617, the new SGSN sends the relocation shipping termination to the previous SGSN, notifying that the UE has been changed to a new network and the previous SGSN returns an acknowledgment message.

Step 618, the above SGSN releases an Iu interface between the previous SGSN and the previous RNC.

If in step 604, the SGSN determines that an S4 interface is used, steps 619-622 must be performed in the present; otherwise, steps B1-B2 are performed in Figure 7. Steps B1-B2 will be described in detail.

Step 619, the SGSN sends the SGW a request for modification of the holder carrying TEID and IP address of the PGW, TEID and IP address of the SGSN, context information of the holder and user identifier information. If the Direct Tunnel is supported, the request contains TEID and IP address of the new RNC.

Step 620, the SGW finds the PGW in accordance with the information provided by the SGSN and sends the PGW a request for modification of the holder including TEID and SGW address and user identifier information.

Step 621, the PGW returns the owner modification response including TEID and PGW address.

Step 622, the SGW returns the holder modification response carrying TEID and address of the S-GW.

Figure 7 is a flow chart of operations after the SGSN determines that an S4 interface is used in accordance with an embodiment of the present invention. As shown in Figure 7, the flow includes steps B1-B2. The new SGSN sends the GGSN a PDP update request carrying TEID and IP address of the new SGSN and the GGSN stores the information and returns a PDP update response to the new SGSN. If the Direct Tunnel is supported, the request contains TEID and IP address of the new RNC.

Step 623, the RAU flow is performed. The flow is technology publicly known to those skilled in the art and no detailed description is provided herein.

Preferably, the determination of the type of access portal of the packet data network can be achieved through, but not limited to, the following two methods: Method 1 Use of the static configuration method. The SGSN statically configures the type of the access portal that the PDN can select and, at the same time, the SGSN also needs to register the type of the access portal selected in the UE context information.

Method 2 Use of the dynamic selection method. The SGSN selects a GGSN through the DNS lookup according to the information provided by the UE and / or user subscription information and the SGSN registers the type of the access portal selected in the context of the UE.

Preferably, the type of access portal of the packet data network may be, but is not limited to, the types of: Type 1, GGSN or PGW; Y Type 2, an independently used GGSN, or the GGSN that serves as the functional module located jointly of the PGW.

Apparatus realizations In accordance with an embodiment of the present invention, an SGSN is provided. Figure 8 is a structural block diagram of the SGSN according to an embodiment of the present invention. As shown in Figure 8, the SGSN encompasses: a sending module 82 adapted to send, when the user equipment initiates an alternation of the GPRS service support node SGSN, a message carrying context information of the user equipment to a Objective SGSN, where the context information includes the type of PDN access portal to which the user equipment is connected. You can see the type of access portal through an extended parameter. For example, the type of access portal can be determined by the FQDN of the selected access portal. When the "context information includes the FQDN of a combined access portal (the GGSN is jointly located in PGW), the access portal is considered as GGSN and is jointly located in PGW and if the context information does not include the FQDN of the combined access portal (the GGSN is located jointly in PGW), the access portal is considered as independent GGSN.

As shown in Figure 8, the SGSN also encompasses: a first determination module 84 adapted to determine a type of access portal; and a module storage 86, connected to the first determination module 84 and the sending module 82, adapted to store the type of access portal in the context information of the user equipment.

The first determination module 84 comprises: a first determination sub-module 842 adapted to determine the type of access portal according to the information previously configured locally; and a second determination submodule 844 adapted to determine the type of access portal according to the information provided by the user equipment and / or subscription information.

It will be explained that the storage module 86, the first determination module 84 and the sending module 82 correspond to the first SGSN (namely, the previous SGSN) in the method embodiments. The reception module 42, the acquisition module 44 and the second determination module 46 correspond to the second SGSN (namely the new SGSN) in the method embodiments.

As shown in Figure 8, the SGSN also encompasses: a reception module 42, an acquisition module 44 and a second determination module 46, which are specifically described as follows.

The reception module 42 is adapted to receive a message from a source SGSN, wherein the message carries the type of access portal of the PDN to which the user equipment is connected, when the user equipment initiates an alternation of SGSN; the acquisition module 44 is connected to the reception module 42 and adapted to acquire the type of access portal of the message; and the second determination module 46 is connected to the acquisition module 44 and adapted to determine, in accordance with the type of access portal, the type of an interface which is used by the SGSN to connect the access portal of the network of data by packages.

The acquisition module 44 comprises: a first acquisition sub-module 442 adapted to acquire the type of access portal that will be PGW, when the message includes the fully qualified domain name of a combined access portal; and a second acquisition submodule 444 adapted to acquire the type of access portal that will be GGSN, when the message does not include the fully qualified domain name of the combined access portal.

The second determination module 46 comprises: a first connection submodule 462 adapted to connect to the access portal of the packet data network through an interface of type S4, in the case that the access portal type is PGW; and a second connection submodule 464 adapted to connect to the access portal of the packet data network through a Gn / Gp type interface, in case the access portal type is GGSN.

As mentioned above, the embodiments of the present invention solve the problem of the lack of a selection mechanism in the relevant art for the SGSN to select a Gn / Gp interface or an S4 interface. Consequently, they achieve the effects that the new SGSN can acquire the type of interface to which the PDN is connected and correctly select the connected network element according to the type of the interface.

Obviously, persons skilled in the art should understand that all the previous modules or steps of the present invention can be realized with a universal computing device. They can be integrated into a single computing device, or distributed in the network consisting of several computing devices. Preferably, they can be made with program codes executable by the computing device, in such a way that they can stored in a storage device that will be executed by the computing device. Or, each of them can be manufactured in an integrated circuit module, or several of these modules or steps can be manufactured in a single integrated circuit module. In this way, the present invention is not limited to the combination of some specific hardware and software.

The above descriptions are only preferred embodiments of the present invention, which are not used to restrict the present invention. For persons skilled in the art, the present invention may have several changes and variations. All modifications, equivalent substitutions, improvements, etc., within the spirit and principle of the present invention are concluded within the scope of the claims of the present invention.

Claims (14)

Claims

1. A method of sending messages, characterized by understanding: When a service support node of the general packet service via radio (GPRS) (SGSN), to which a user equipment is connected, changes from a first SGSN to a second SGSN, the first SGSN sends a message to the second SGSN Context information of the user equipment, wherein the context information covers a type of access portal of a packet data network to which the user equipment is connected.

2. The method according to Claim 1, characterized in that, after the first SGSN sends the message to the second SGSN, the method further comprises: The second SGSN receiving the message and acquiring from the message the type of access portal of the packet data network to which the user equipment is connected and determining, according to the type of access portal, the type of an interface which is used by the second SGSN to connect the access portal of the packet data network.

3. The method according to Claim 2, characterized in that the second SGSN acquiring from the message the type of access portal of the packet data network to which the user equipment is connected, consists of: The second SGSN acquiring the type of access portal of a fully qualified domain name of the access portal contained in the message, where when the message contains the fully qualified domain name of a combined access portal, the portal type of acquired access is the access portal of the packet data network (PGW); and when the message does not contain the fully qualified domain name of the combined access portal, the type of access portal acquired is the GPRS access portal support node (GGSN).

4. The method according to claim 3, characterized in that the second SGSN determining, according to the type of access portal, the type of an interface selected by the second SGSN, comprises: In the case that the access portal type is PGW, determining that the connection to the access portal of the packet data network is through an interface of type S4; Y In the case that the type of access portal is GGSN, determining that the connection to the access portal of the packet data network is through a Gn / Gp type interface.

5. The method according to Claim 1, characterized in that, before the first SGSN sends the message to the second SGSN, the method further comprises: The first SGSN determining the type of access portal and storing the type of access portal in the context information of the user equipment.

. 6. The method according to claim 5, characterized in that the first SGSN determining the type of access portal, consists of: The first SGSN determining the type of access portal according to the information previously configured locally; Y The first SGSN determining the type of access portal according to the 'information provided by the user equipment and / or subscription information.

7. A service support node of the general packet service via radio (GPRS) (SGSN), characterized by consisting of: A sending module adapted to send, when a user equipment initiates an alternation of the GPRS service support node, a message carrying context information of the user equipment to a target SGSN, wherein the context information encompasses a type of access portal of the packet data network to which the team of user is connected.

8. The SGSN according to Claim 7, characterized in that the SGSN also comprises: A first determination module adapted to determine the type of access portal; Y A storage module adapted to store the type of access portal in the context information of the user equipment.

9. The SGSN according to Claim 8, characterized in that the first determination module consists of: A first determination submodule adapted to determine the type of access portal according to the information previously configured locally; Y A second determination submodule adapted to determine the type of access portal according to the information provided by the user equipment and / or subscription information.

10. The SGSN according to any of Claims 7-9, characterized in that the SGSN further comprises: A reception module adapted to receive, when the user equipment initiates an SGSN alternation, a message from a source SGSN, wherein the message carries the type of access portal of the packet data network to which the equipment user is connected; An acquisition module adapted to acquire the type of message access portal; Y A second determination module adapted to determine, in accordance with the type of access portal, the type of an interface which is used by the SGSN to connect the access portal of the packet data network.

11. The SGSN according to Claim 10, characterized in that the acquisition module consists of: A first acquisition submodule adapted to acquire the type of access portal that will be PGW, when the message contains a fully qualified domain name of a combined access portal; Y A second acquisition submodule adapted to acquire the type of access portal that will be GGSN, when the message does not contain the fully qualified domain name of the combined access portal.

12. The SGSN according to Claim 11, characterized in that the second determination module comprises: A first connection submodule adapted to connect to the access portal of the packet data network through an interface of type S4, in the case that the access portal type is PGW; Y A second connection submodule adapted to connect to the access portal of the packet data network through a Gn / Gp type interface, in case the access portal type is GGSN.

13. The SGSN according to Claim 7, characterized in that when the message contains the fully qualified domain name of a combined access portal, the type of access portal is PGW; and when the message does not contain the domain name • fully qualified from the combined access portal, the type of access portal is GGSN.

14. The method according to claim 1, characterized in that when the message contains the fully qualified domain name of a combined access portal, the type of access portal acquired is the access portal of the packet data network (PGW). ); and when the message does not contain the fully qualified domain name of the combined access portal, the type of access portal acquired is the GPRS access portal support node (GGSN).