Machine To Machine (M2M) communication is also called as machine type communication, which is the communication between a terminal and an application server typically, and the terminal is called as a MTC User Equipment (MTC UE) and the application server is called as a MTC Server. An action of the MTC UE in the M2M communication is restrained by service subscription data, and the MTC Server manages the MTC UE in the M2M communication according to the service subscription data.
In the 2G/3G Long Term Evolution (LTE) access, the M2M communication mainly takes a Packet Service (PS) network as a bottom layer bearer network, which implements service layer communication between the MTC UE and MTC Server. FIG. 1 is a schematic diagram of framework of an M2M communication entity accessing an Evolved Packet System (EPS) in the related art.
In FIG. 1, the bottom layer bearer network includes: an Evolved Universal Terrestrial Radio Access Network (E-UTRAN), a Mobility Management Entity (MME), a Serving Gateway (S-GW or SGW), a Packet Data Network Gateway (PDN GW, P-GW or PGW), a Home Subscriber Server (HSS) and a Policy and Charging Rules Function (PCRF) entity. Wherein, a major network element of the E-UTRAN is an Evolved NodeB (eNodeB).
In FIG. 1, the MTC UE gains access to an EPS network through the E-UTRAN (eNodeB), and after an IP address is allocated, an IP channel can be established between the MTC UE and MTC Server, thereby implementing upper layer service communication between the MTC UE and MTC Server. The IP channel established between the MTC UE and MTC Server is a logical IP channel of which a physical path goes through the eNodeB, S-GW and P-GW.
Currently, one mode for implementing the M2M communication is to establish one service layer interface protocol on the IP channel between the MTC UE and MTC Server, and the interaction of service data is performed between the MTC UE and MTC Server through the service layer interface protocol. Meanwhile, the MTC Server also implements control on the MTC UE through the service layer protocol.
FIG. 2 is a flow diagram of a MME allocating a PGW to a MTC UE in the existing process of implementing the M2M communication by establishing one service layer interface protocol on an IP channel between the MTC UE and MTC Server, and as shown in FIG. 2, following steps are mainly included.
In step 200, the MTC UE initiates an attach request to the MME.
In step 201, the MME receives the attach request and sends an Update location request to a HSS, and the HSS downloads the subscription data of the MTC UE from the MME through an Update location response, wherein the subscription data part used for M2M access control is included.
In step 202, the MME selects an appropriate SGW and PGW for the MTC UE according to the subscription data returned by the HSS.
Currently, the HSS mainly uses the following two modes to indicate the MME how to acquire a PGW address.
The first mode: the HSS appoints one Access Point Name (APN) and one PGW specific address in the Update location response. With the first mode, the HSS appoints one PGW specific address (the APN and PGW address) of a home network, and the MME acquires the PGW of the home network definitely according to the PGW address indicated by the HSS, that is, the HSS replaces the MME to select the PGW.
The second mode: the HSS appoints one APN and one indication used for indicating the MME whether to select the PGW of a home network or visited network in the Update location response. With the second mode, the HSS indicates the MME to select the PGW, and a mechanism of the MME selecting the PGW is: the MME extending the APN into a domain name in the form of: APN.MNC.MCC.XXYY, and then requesting a Domain Name Server (DNS) to analyze the domain name into one PGW address. Wherein, a Mobile Network Code (MNC) is used to identify one specific mobile network, and the visited network and home network may have different mobile network codes; a Mobile Country Code (MCC) is used to identify a country to which the mobile network belongs; XXYY is a service type name, e.g. GPRS, which indicates that the APN is one PGW which provides a GPRS service type.
If the HSS uses the second mode to indicate the MME how to acquire the PGW address, and the HSS indicates that the MME is required to allocate the PGW of the home network, thus, the HSS needs to provide one APN Operator Identifier (APN-OI), and the APN-OI is in the form of a word string APN.MNC.MCC; after receiving the indication from the HSS, the MME replaces the corresponding part in the domain name APN.MNC.MCC.XXYY extended by the APN with the APN-OI, and then according to the domain name, it can request the DNS of the home network to analyze the PGW address of the home network.
If the HSS uses the second mode to indicate the MME how to acquire the PGW address, and the HSS indicates the MME to allocate the PGW of the visited network, thus, the MME generates the domain name in the form of APN.MNC.MCC.XXYY according to its own mobile network code, and requests the DNS of the local network to analyze the PGW address of a local network according to the domain name.
Compared with the second mode, in the first mode, the APN does not include an Operator Identifier (OI) and the above “MNC.MCC” part.
In step 203, the MME sends a Create bearer request to the selected SGW/PGW to request the SGW/PGW to create an appropriate bearer for the MTC UE.
In step 204, if the PGW needs to acquire policy data from PCC to establish the appropriate bearer, the PGW interacts with the PCC to obtain a PCC policy.
In step 205, the PGW creates the bearer for the MTC UE, and returns a Create bearer response.
In step 206, the MME sends an attach response to the MTC UE.
Due to the particularity of the M2M communication, in practical applications, a plurality of MTC UEs may have identical management attributes, therefore, these MTC UEs which have the identical management attributes can constitute one MTC group, and the same access control can be executed on one MTC group, such as access time control, access times control and access region restriction and so on.
With regard to the MTC UEs under management of the MTC group, during the charging, the maximum flow of a certain MTC group may be required to be limited, and a data gateway is required to generate charging data according to the MTC group. According to the requirement, it is required to allocate each MTC UE in the same MTC group to the same PGW. However, in the related art, since the allocation of PGW to the MTC UE is indicated by the HSS and obtained according to analyzing the APN, therefore, it fails to guarantee that the MTC UEs in the same MTC group are allocated to the same PGW, thereby failing to guarantee that the maximum flow and charging of each MTC group are effectively limited.
In the related art, the MME acquires a group identifier of the MTC group to which a MTC UE belongs, and allocates the same PGW to MTC UEs with the same group identifier. However, when the MTC UE attaches, if other MTC UEs in the MTC group to which the MTC UE belongs do not attach to the same MME, thus, according to the existing method, a PDN-GW address can only be statically configured in the HSS, otherwise they fails to be selected on the same PGW. Moreover, if the MTC UE is in a roaming scenario, MMEs to which the MTC UEs attach may be different in the group, thus according to that the PGWs analyzed by the same APN are different, using the MME to select the same PGW for the MTC UEs in the MTC group is also inappropriate.