WO2008125050A1

WO2008125050A1 - A method and a wireless communication system for realizing network handover

Info

Publication number: WO2008125050A1
Application number: PCT/CN2008/070689
Authority: WO
Inventors: Jing Liu; Yan Peng; Bin Xia
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2007-04-13
Filing date: 2008-04-09
Publication date: 2008-10-23
Also published as: CN101287283A; CN101287283B

Abstract

The exemplary embodiments of the present invention provide a method and a system for realizing network handover, which belong to wireless communication technical field. The method includes: sending the network layer mobility management information carried in a link layer handover message, during a handover process of a terminal from a serving network to a destination network; using the network layer mobility management information carried in the link layer handover message to perform network layer mobility management. The wireless communication system includes: a terminal, a destination network PoS, and a serving network PoS. The network layer mobility management information is sent in the link layer handover message through the method and wireless communication system provided by the schemes of the present invention, and the corresponding mobility management can be performed prior to the network layer handover by using the link layer handover message, which carries the network layer mobility management information, thereby reducing the handover delay and improving the network handover capability.

Description

Method for implementing network switching and wireless communication system

The present invention relates to the field of wireless communication technologies, and in particular, to a technology for implementing network switching.

Background technique

When the terminal moves from the current serving cell to the neighboring cell, the terminal switches to the neighboring network by the current serving network service point (Serving PoS) according to the channel quality, so as to ensure the communication quality, the handover is performed not only in the same network. , can also be carried out between different networks. Today's mobile communication networks have evolved into a coexistence of multiple networks such as microcellular networks and macrocellular networks, such as microcellular networks supporting the IEEE 802.11 standard and supporting 3GPP, 3GPP2 IEEE 802.16. A standard macro cellular network. Cellular networks supporting different standards may overlap each other. Therefore, when a terminal roams between these different networks, switching between different networks occurs. In order to enable the terminal to switch between different networks, it can automatically select the best network connection type to achieve seamless handover and connectivity. The IEEE802.21 standard introduces a new protocol function in the existing mobility management protocol stack. Layer, called the Media Independent Handover (MIH) protocol layer. Figure 1 is a schematic diagram of the MIH protocol layer. As shown in Figure 1, the MIH protocol layer is located between the upper layer protocol and the lower layer protocol of the original mobility management protocol stack. Its main function is to provide a unified interface to the upper layer users, thereby shielding the underlying different access technologies. The upper layer protocol mainly includes mobility management protocols such as MIP (Mobile Internet Protocol) v4/ _V 6 and handover policies, transmission and applications, etc. The lower layer protocols include various access network link layer protocols, such as IEEE802. 3. IEEE802.11, IEEE802.16 and 3GPP.

The process of implementing the network switching mainly includes the link layer switching and the network layer mobility management process. Currently, the method of implementing the network switching is to perform the switching of the link layer and the switching of the network layer in a simple sequence before and after the switching. First, the link layer switching preparation and negotiation are performed; then, the link layer switching is performed; then, the network layer mobility management is performed, that is, the network layer mobility management protocol performs the network layer mobility in the switched network. management.

2 is a schematic flow chart of terminal triggered network switching in the IEEE802.21 protocol. As shown in FIG. 2, an information server is used to store characteristics of each neighbor network. The terminal is a mobile node (MN, Mobile Node), and the service network PoS is a current network PoS where the MN is located, such as an attachment point of the current network. Or access the router. The terminal performs the purpose by querying each candidate network PoS (Candidate PoS) for available network resources. The selection of the standard network PoS includes the following steps:

Step 201: The MN sends a message request (MIH_Get_Information request) message to the information server.

The MN queries the information of the neighbor network by sending an MIH_Get_Information request message to the information server.

Step 202: The information server sends a MIH_Get_Information response message to the MN.

The information server returns an MIH_Get_Information response message to the MN to provide information about the neighbor network. The MN performs selection according to the neighbor network information returned by the information server, thereby further determining the candidate network for handover.

Step 203: The MN sends a terminal switching candidate query request to the service network PoS.

( MIH_MN_HO_Candidate_Query request ) message.

The MN triggers the handover by sending a MIH_MN_HO_Candidate_Query request message to the serving network PoS. The request message contains a list of possible candidate networks.

Step 204: The service network PoS sends an inter-network handover resource query request (MIH_N2N_HO_Query_Resources request) message to each candidate network PoS.

After receiving the message, the service network PoS sends a MIH_N2N_HO_Query_Resources request message to each candidate network PoS, that is, the available network resources are queried to each candidate network PoS.

Step 205: Each candidate network PoS sends an inter-network handover resource query response (MIH_N2N_HO_Query_Re source s response ) message to the service network PoS.

Each candidate network PoS returns the query result of each candidate network resource to the service network PoS through the MIH_N2N_HO_Query_Resources response message.

Step 206: The service network PoS sends a message of the MIH MN HO Candidate Query response to the terminal.

The service network PoS returns the query result of each candidate network resource to the MN through the MIH_MN_HO_Candidate_Query response message. The MN performs the determination of the target network based on the received query result.

Step 207: The MN sends a MIH MN HO Candidate Commit request message to the service network PoS.

After the target network is determined, the MN sends a MIH_MN_HO_Candidate_Commit request message to the serving network PoS, indicating that the terminal is ready to start the connection with the new network to establish a link layer.

Step 208: The service network PoS sends a network handover candidate execution request to the target network PoS. (MIH Net HO Candidate Commit request ) message.

After receiving the message, the service network PoS forwards the MIH Net HO Candidate Commit request message to the selected target network PoS to notify the target network: The MN is ready to start the connection with the new network to establish the link layer. Here, it is assumed that the target network is the candidate network 1.

Step 209: The target network PoS sends a network handover candidate execution response to the service network PoS.

(MIH Net HO Candidate Commit response ) message.

Step 210: The service network PoS sends a MIH MN HO Candidate Commit response message to the MN.

The service network PoS forwards the MIH_MN_HO_Candidate_Commit response message to the MN to inform the result of the handover submission. After receiving the message, the MN starts to establish a connection with the target network and performs handover.

Step 211: The MN sends a terminal handover complete request (MIH_MN_HO_Complete request) message to the target network PoS.

After the link layer handover and the high layer handover are completed, the MN sends a MIH_MN_HO_Complete request message to the target network PoS for notifying the target network that the MN has successfully switched to the target network.

Step 212: The target network PoS sends an inter-network handover completion request to the service network PoS.

( MIH_N2N_HO_Complete request ) message.

Step 213: The service network PoS sends an inter-network handover completion response (MIH_N2N_HO_Complete response) message to the 0-standard network PoS.

After receiving the message, the service network PoS processes the network resources and returns the processing result to the target network PoS through the MIH_N2N_HO_Complete response message.

Step 214: The target network Po S sends a terminal handover completion response (MIH_MN_HO_Complete response) message to the MN.

The target network PoS forwards the MIH MN HO Complete response message to the MN, and returns the processing result of the original service network to the MN.

Figure 2 specifically shows the link layer handover procedure. For the network layer, there are corresponding mobility management protocols for different handover requirements, such as Fast Mobile Internet Protocol (FMIP, Fast Mobile) for accelerating MN handover. IP) protocol, and Network based Local Mobility Management (NetLMM) protocol for reducing handover delay. The following takes the FMIP protocol as an example to specifically describe the handover process of the network layer under a specific mobility management protocol. Figure 3 is a schematic diagram of the FMIP protocol switching process. Referring to Figure 3, the former access router (PAR) is the current access router connected to the MN, and may correspond to the service network PoS and the new access router in Figure 2. NAR, New Access Router) can correspond to the target network PoS in Figure 2, according to FMIP The protocol, before the MN accesses the NAR, has obtained the newly configured care-of address (NCoA, New Care-of Address), so that when the MN is connected to the NAR, the care-of address can be used immediately, including the following steps:

Step 301: The MN sends a Router Solicitation for Proxy Advertisement (RtSolPr) message to the PAR.

When the MN predicts that it is about to switch or discovers that a new access point exists, it sends an RtSolPr message to the PAR, which is used to inform the PAR that the MN is about to switch and requests the information needed for the handover.

Step 302: The PAR sends a proxy route advertisement (PrRtAdv, Proxy Router Advertisement) message to the MN.

The PAR returns a PrRtAdv message to the MN in response, which provides the MN with the network prefix information used by the NAR.

Step 303: The MN sends a Fast Binding Update (FBU) message to the PAR.

When the MN is ready to switch and determine the access point to be handed over, the network prefix information of the NAR corresponding to the new access point is obtained from the PAR to perform NCoA configuration, and the network prefix information is carried in the proxy router advertisement message. After the NCoA is configured, the MN sends an FBU message to the PAR for NCoA binding and address collision detection through the PAR and the NAR before the handover, and the PAR can also establish a handover notification process to establish a relationship between the PAR and the NAR. The data channel forwards the data packet sent to the old care-of address to the MN's NCoA.

Step 304: The PAR sends a handover initiation (HI, Handover Initiate) message to the NAR.

After receiving the FBU message from the MN, the PAR sends an HI message to the NAR to notify the NAR that the MN is ready to perform fast switching. The message carries the NCoA information configured by the MN. The NAR can perform NCoA binding and address conflict detection.

Step 305: The NAR sends a handover acknowledgement (HAck, Handover Acknowledgement) message to the PAR.

After receiving the HI message, the NAR performs address conflict detection based on the obtained NCoA information. If the address conflicts, the NAR reconfigures the NCoA for the MN and returns the information to the PAR via the HAck message.

Step 306: The PAR sends a Fast Binding Acknowledge (FBack) message to the MN.

After receiving the fast binding acknowledgement (HAck) message, the PAR returns the information carried by the PAR to the MN through the FBack message. Step 307: The MN disconnects from the PAR.

Step 308: The PAR forwards the data packet to the NAR.

The NAR stores the received data packets for use in subsequent processes.

Step 309: The MN establishes a connection with the NAR.

Step 310: The MN sends a Fast Neighbor Advertisement (FNA) message to the NAR. Once the MN accesses the NAR, the MN sends an FNA message to the NAR, notifying that the MN has accessed the NAR.

Step 311: The new access router forwards the stored data packet to the MN.

According to the requirements of the FMIP protocol, step 301 to step 306 should be performed before the link layer handover, that is, before the link layer handover, the MN needs to obtain the prefix information of the target network through the network layer protocol message in advance, and configure the MN's NCoA, the process of detecting address conflicts.

Through the above analysis of the method for switching between the link layer and the network layer, it can be seen that the current network switching process uses a method of performing link layer switching first, and then performing network layer switching in order to implement network switching. When the session is re-established, the switching delay is increased, and the risk of switching off calls is increased. At the same time, because the network layer mobility management protocol is not negotiated between the terminal and the network side during the entire handover process, the terminal layer and the network side support different mobility management protocols may be caused after the terminal completes the link layer handover. The failure of the entire handover increases the risk of dropped calls after the handover.

In summary, the current switching mode is adopted, and the switching performance is low. Summary of the invention

In order to improve the performance of the network switching, the embodiment of the present invention provides a method for implementing network switching and a wireless communication system, where the technical solution:

A method for implementing network switching, the method comprising:

During the process of performing link layer handover by the service network to the target network, the network layer mobility management information is carried in the link switch message;

Network layer mobility management is performed using network layer mobility management information carried in the link layer handover message. A wireless communication system, the system comprising:

Terminal, target network PoS, service network PoS;

The terminal is configured to receive a link layer handover message that carries network layer mobility management information sent by the service network PoS or the target network PoS, and uses the network layer mobility management information carried in the link layer handover message, Perform network layer mobility management, and when the terminal triggers the handover, use the network layer mobility management information carried in the link layer handover message to determine the target network and perform network layer mobility management;

The service network PoS is configured to receive a link layer handover message that is sent by the terminal or the target network PoS and that carries the network layer mobility management information, and uses the network layer mobility management information carried in the link layer handover message. Perform network layer mobility management, and when the network side triggers handover, use the network layer mobility management information of the candidate network carried in the link layer handover message to determine the target network and perform network layer mobility management;

The target network PoS is configured to receive a link layer handover message from a terminal or a serving network PoS, and perform network Layer mobility management.

The method for implementing network handover and the wireless communication system provided by the technical solution of the embodiments of the present invention carry network layer mobility management information in a link switch message, and can use a link layer handover message carrying network layer mobility management information. The corresponding mobility management is performed in advance of the network layer switching, which can reduce the handover delay and improve the performance of the network handover. DRAWINGS

1 is a schematic diagram of a MIH protocol layer in the prior art;

2 is a schematic flowchart of implementing network switching in the IEEE802.21 protocol in the prior art;

3 is a schematic diagram of a network layer switching process of a FMIP protocol in the prior art;

4 is a flowchart of a method for implementing network switching according to a first embodiment of the present invention;

FIG. 5 is a flowchart of a method for implementing network switching according to a second embodiment of the present invention;

FIG. 6 is a flowchart of a method for implementing network switching according to a third embodiment of the present invention;

FIG. 7 is a flowchart of a method for implementing network switching according to a fourth embodiment of the present invention;

FIG. 8 is a flowchart of a method for implementing network handover according to a fifth embodiment of the present invention;

FIG. 9 is a schematic structural diagram of a wireless communication system for implementing network handover according to a sixth embodiment of the present invention; FIG. 10 is a schematic structural diagram of a mobility management system during network handover according to an embodiment of the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings.

A method for implementing network handover according to an embodiment of the present invention is: carrying a network layer mobility management information in a link switching message, and transmitting, in a process of performing a link layer handover by a service network to a target network PoS. The network layer mobility management information carried in the link layer switching message completes the corresponding network layer mobility management function.

The media independent switching standard IEEE802.21 is taken as an example below. Six embodiments are described to illustrate a method for implementing network switching by using network layer mobility management information by using link layer switching messages. The first, third, fourth and fifth embodiments are terminal-triggered fast network switching supporting FMIP, Hierarchical Mobile IP (IPIP), Proxy Mobile IP (PMIP) and NetLMM protocol respectively. Process, the second embodiment is a network side triggered network switching process that supports FMIP. Since the embodiment of the present invention adopts a method for transmitting network layer mobility management information in a link switch message, the HMIP protocol, the PMIP protocol, and the NetLMM protocol may also be referred to as a fast hierarchical mobile IP protocol and a fast proxy mobile IP, respectively. Protocol and fast local local mobility management protocol. It should be noted that the link layer handover message in the foregoing six embodiments may also be a link layer handover message defined in the 3GPP, 3GPP2, and IEEE 802 series standards.

Embodiment 1:

FIG. 4 is a flowchart of a method for implementing network handover according to a first embodiment of the present invention. In this embodiment, the MN triggers a network handover process that supports the FMIP protocol. In this embodiment, first, the link layer handover message is used to negotiate the mobility management protocol supported by the MN and the network side; then, the link layer handover message is used to acquire the network information of the target network PoS including the network prefix, The process of dynamic network discovery is completed in advance; in addition, the link layer switching message is used to perform the configuration of the care-of address and the address conflict detection under the PoS of the target network, and the address configuration and the collision detection are completed in advance; the interaction between the service network PoS and the target network PoS is performed. , notify the target network PoS in advance to establish the data channel of the link layer and the network layer at the same time. Therefore, in this embodiment, the network layer mobility management information in the link layer switching message is: mobility management protocol information of the candidate network, network prefix information of each candidate network, configured NCoA information, and detected NCoA information. . Referring to FIG. 4, the following steps are specifically included:

Step 401: The MN sends a MIH Get lnformation request message carrying the mobility management protocol request to the information server.

In this embodiment, the MIH_Get_Information request message sent by the MN to the information server carries the request mobility management protocol information element (TYPE_IE_SUPPORTED_MOBILITY_MANAGEMENT_PROTOCOL) for requesting the information server to acquire the mobility management protocol supported by each candidate network.

Step 402: The information server sends a MIH Get lnformation response message carrying the mobility management protocol information supported by each candidate network to the MN.

In this embodiment, the information server returns an MIH_Get_Information response message to the MN, where the message carries the mobility management protocol information supported by each candidate network.

Step 403: The MN sends, to the serving network PoS, a terminal handover candidate query request (MIH_MN_HO_Candidate_Query request) message carrying the network prefix request of each candidate network.

In this embodiment, the MN sends a terminal handover candidate query request to the service network PoS.

The message (MIH_MN_HO_Candidate_Query request) triggers the handover, and the message carries the network prefix request information of each candidate network.

Step 404: The service network PoS sends an MICH_N2N_HO Query Resources request message carrying the network prefix request information of each candidate network to each candidate network PoS.

In this embodiment, after the service network PoS receives the message, it sends the message to each candidate network PoS.

The MIH_N2N_HO_Query_Resources request message is used to query available resources of each candidate network, and the The network prefix request information of each candidate network is also carried in the information, and is used to request a network prefix (Network Prefix) from each candidate network.

Step 405: Each candidate network PoS sends an inter-network handover resource query response (MIH_N2N_HO_Query_Resources response) message to the service network PoS.

In this embodiment, each candidate network returns a MIH_N2N_HO_Query_Resources response message to the serving network PoS, where the message carries the network prefix of each candidate network.

Step 406: The serving network sends an inter-network handover candidate network query response (MIH_MN_HO_Candidate_Query request) message carrying the network prefix of each candidate network to the MN.

In this embodiment, the serving network PoS forwards the MIH_MN_HO_Candidate Query request message to the MN, and returns the resource query result and the network prefix of each candidate network to the MN.

The terminal performs the mobility management function while performing the selection of the target network according to the query result of each candidate network resource. The method for performing the mobility management function includes: obtaining a network layer mobility management protocol supported by each neighbor network or candidate network by parsing a link layer handover message carrying network layer mobility management protocol information supported by the neighbor network or the candidate network, In the neighbor network that supports the same network layer protocol as the terminal, the handover candidate network is determined or the candidate network that is the same network layer protocol as the terminal support is determined. Here, the neighbor network, the candidate network, and the target network range from large to small. The method for determining the target network in the prior art is as follows: First, the candidate network is selected from the neighbor network according to the characteristics of the neighbor network, and the second step: selecting the target network from the candidate network according to the resource query result, the embodiment of the present invention The mobility management protocol negotiation process has been added. This process can be performed in the first step or in the second step. After the target network is determined, it is further determined whether the network prefix of the target network is consistent with the subnet prefix of the serving network. When the network prefix of the target network is inconsistent with the subnet prefix of the serving network, the MN is performed according to the prefix of the selected target network. The configuration of the NCoA.

Step 407: The MN sends a MIH MN HO Candidate Commit request message carrying the configured NCoA information to the serving network PoS.

In this embodiment, after the target network PoS is selected, the MN sends an MIH MN HO Candidate Commit request message to the service network PoS, where the message may carry the NCoA information configured by the terminal. In this embodiment, it is assumed that the target network PoS is the candidate network 1.

Step 408: The service network PoS sends a network handover candidate execution request (MIH_Net_HO_Candidate_Commit request) message carrying the configured NCoA information to the target network PoS.

In this embodiment, the service network PoS sends a MIH_Net_HO_Candidate_Commit request message to the target network PoS, and forwards the configured NCoA information to the target network PoS.

The target network extracts the NCoA information configured by the MN from the network handover candidate execution request message repeatedly. Address detection, if the address conflicts, the target network reconfigures the NCoA information for the MN.

Step 409: The target network PoS sends a network handover candidate execution response (MIH_Net_HO_Candidate_Commit response) message carrying the detected NCoA information to the serving network PoS.

In this embodiment, the target network PoS sends a network handover candidate execution response to the service network PoS.

(MIH Net HO Candidate Commit response ) message, returning the result after the address detection. This message can carry the detected NCoA information.

Step 410: The service network PoS sends a MIH MN HO Candidate Commit response message to the MN.

In this embodiment, the service network PoS sends an MIH_MN_HO_Candidate_Commit response message to the MN, and the detected result is forwarded to the MN by the message, and the service network PoS starts to establish a network layer data channel with the target network PoS, and performs a service network PoS. Forwarding of data packets with the target network PoS for network layer switching.

Step 411: The MN sends a terminal handover complete request (MIH_MN_HO_Complete request) message to the target network PoS.

After the link layer handover and network layer handover procedures are performed, the MN sends to the target network PoS.

The MIH_MN_HO_Complete request message is used to notify the target network that the MN has successfully switched to the target network. After receiving the message, the target network PoS starts forwarding the stored data packets to the MN.

Step 412 - Step 414 is the same as step 212 - step 214 in the method shown in Figure 2, and will not be repeated here. In this embodiment, the mobility management protocol supported by the MN and the network side is negotiated first, so as to avoid inconsistency and incompatibility of the mobility management protocols supported by the MN and the network side after the link layer is switched to the new network. The user business cannot be re-established and the risk of dropped calls ensures that the entire switching process is carried out normally.

In this embodiment, the MN and the network side may also negotiate the mobility management protocol supported by the two parties in the handover preparation phase, that is, in the process of triggering the handover by the MN, the service network PoS receives the mobility management protocol supported by each candidate network. After the MIH_N2N_HO_Query_Resources response message, the mobility management protocol information supported by each candidate network is returned to the MN through the corresponding response message MIH_MN_HO_Candidate_Query response message, and the MN assists the selection of the target network according to the obtained mobility management protocol supported by each candidate network.

Similarly, in this embodiment, the MIH_Get_Information response message returned by the information server can also carry the network prefix of each neighbor network, so that the MN obtains the network prefix of each neighbor network.

In this embodiment, the network discovery, the network address configuration, and the address conflict detection are completed in advance by using the link layer switching message, thereby shortening the handover delay, thereby improving the user experience.

In addition, in this embodiment, the interaction between the service network PoS and the target network PoS can be notified in advance before the handover. The target network simultaneously establishes the data channel of the link layer and the network layer, reduces the connection process of the link layer data channel and the network layer data channel after switching to the new target network, and greatly reduces the data caused by the handover process. Interruption time.

Embodiment 2:

FIG. 5 is a flowchart of a method for implementing network handover according to a second embodiment of the present invention. This embodiment is a network switching process in which the network side triggers the FMIP protocol. In this embodiment, the network layer mobility management information in the link layer switching message is: mobility management protocol information of the candidate network and its request information, network prefix information of each candidate network, request information, and configured NCoA information. And detected NCoA information. Specific steps are as follows:

Step 501: The service network PoS sends a MIH Get lnformation request message carrying the mobility management protocol request to the information server.

In this embodiment, the service network PoS sends an MIH_Get_Information request message to the information server, where the information element TYPE_IE_POA_SUB ET_INFORMATION carrying the request mobility management protocol is used to request the information server to obtain the supported mobility management protocol of each candidate network. .

Step 502: The information server sends a MIH_Get_Information response message carrying the mobility management protocol information supported by each candidate network to the serving network PoS.

Step 503: The service network PoS sends a MIH Net HO Candidate Query request message to the MN.

In this embodiment, the MIH_Net_HO Candidate Query request message is sent to the MN through the service network PoS to trigger the handover.

Step 504: The MN sends a network handover candidate network query response to the service network PoS.

(MIH Net HO Candidate Query response ) message.

Step 505: The service network PoS sends an inter-network handover resource query request (MIH_N2N_HO_Query_Resources request) message carrying a network prefix request to each candidate network PoS.

In this embodiment, after receiving the response message, the serving network PoS sends an MIH_N2N_HO_Query_Resources request message to each candidate network, respectively, for querying each candidate network for available resources. At the same time, the message may also carry the information of the network prefix request, and is used to request the network prefix from each candidate network.

Step 506: Each candidate network PoS sends an inter-network handover resource query response (MIH_N2N_HO_Query_Resources response) message carrying the network prefix to the serving network PoS.

In this embodiment, each candidate network sends a MIH_N2N_HO_Query_Resources response message to the serving network PoS, where the message carries the network prefix of each candidate network.

The service network performs the mobility management protocol information supported by each candidate network and the returned resource query result. The choice of the target network.

Step 507: The service network PoS sends a network handover candidate execution request (MIH_Net_HO_Candidate_Commit request) message carrying the configured NCoA request information to the target network PoS.

In this embodiment, after selecting the target network, the serving network PoS sends an MIH Net HO Candidate Commit request message to the target network PoS, and further determines whether the network prefix of the target network is consistent with the subnet prefix of the serving network, when the target network When the network prefix is inconsistent with the subnet prefix of the serving network, the message carrying the NCoA requesting the MN in the target network PoS needs to be carried in the message. In this embodiment, it is assumed that the target network is the candidate network 1.

After receiving the message, the target network performs NCoA configuration for the MN according to its own network prefix information.

Step 508: The target network PoS sends a MIH_Net HO Candidate Commit response message carrying the configured NCoA information to the serving network PoS.

In this embodiment, the target network PoS sends a MIH_Net HO Candidate Commit response message to the service network PoS, and returns the result of the address configuration, where the message carries the configured NCoA information. At the same time, the service network PoS establishes a network layer data channel with the target network PoS in advance, and forwards the data packet between the service network PoS and the target network PoS.

Step 509: The service network PoS sends a MIH MN HO Candidate Commit request message carrying the configured NCoA information to the MN.

In this embodiment, the serving network PoS sends a MIH_MN_HO_Candidate_Commit request message to the MN, and returns the result of the address configuration to the MN, where the message carries the configured NCoA information.

Step 510: The MN sends a terminal switch candidate execution response to the service network PoS.

(MIH MN HO Candidate Commit response ) message.

Step 511: The MN sends a terminal handover complete request (MIH_MN_HO_Complete request) message to the target network PoS.

After the link layer handover and the network layer handover process are performed, the MN sends a MIH_MN_HO_Complete request message to the target network PoS to notify the target network that the MN has successfully switched to the target network. After receiving the message, the target network PoS starts forwarding the stored data packets to the MN.

Step 512-step 514 is the same as step 212-step 214 in the method shown in Fig. 2, and will not be repeated here. In this embodiment, the MIH_N2N_HO_Query Resources response message returned by each candidate network PoS may also carry the mobility management protocol supported by each candidate network. In the process of triggering the handover on the network side, after receiving the message, the service network helps the selection of the target network according to the obtained mobility management protocol supported by each candidate network.

Similarly, in this embodiment, the MIH_Get_Information response message returned by the information server can be carried. Network information such as a network prefix of each candidate network obtains network information of each candidate network.

In this embodiment, the MN and the network side are negotiated by the service network to negotiate the mobility management protocols supported by the two parties before the handover is performed, thereby avoiding the link layer switching to the new network, due to the mobility management protocol supported by the MN and the network side. The inconsistency and incompatibility of the user service cannot be re-established and the risk of dropped calls ensures the normal handover process. At the same time, the embodiment can also complete the network discovery, network address configuration, and address conflict detection in advance by using the link layer switching message. Therefore, the delay of switching is shortened, thereby improving the user experience.

In addition, in this embodiment, the interaction between the service network PoS and the target network PoS is performed before the network layer is switched, and the target network can be notified in advance to establish the data channel of the link layer and the network layer at the same time, and after switching to the new target network, the chain is sequentially performed. The process of establishing the data channel of the road layer and the data channel of the network layer greatly reduces the data interruption time caused by the switching process.

Embodiment 3:

FIG. 6 is a flowchart of a method for implementing network switching according to a third embodiment of the present invention. This embodiment is a network switching process in which the MN triggers the HMIP protocol. The purpose of the HMIP protocol is to introduce a Mobile Anchor Point (MAP) between the home agent (HA) and the Access Router (AR) by using a hierarchical structure, so that the MN is in the MAP domain. The handover, that is, the handover between the ARs under the MAP does not need to be bound to the remote HA, but the local MAP performs a binding update of the local forwarding address (LCoA, on-link CoA), that is, only Register a new LCoA with the MAP to reduce the delay of the handover. Only when the MAP domain is switched, it is necessary to simultaneously reconstruct the MN's global forwarding address (RCoA, Regional CoA) and LCoA, and establish binding with the HA and the new MAP. In this embodiment, the network layer mobility management information in the link layer switching message is: network prefix information of the MAP domain to which each candidate network belongs, network prefix information of each candidate network and its request information, configured LCoA information, and detection. After the LCoA information.

Described in this embodiment is the handover of the MN in the MAP domain, and the MN performs the configuration of the new link care-of address (NLCoA, New on-link CoA) address in the MAP domain according to the selected target network, and uses the link layer handover. The message sends the configured LCoA information to the target network PoS. After receiving the LCoA information, the target network performs DAD detection and returns the detection result to the MN. After the handover is completed and the MN successfully switches to the target network, the MN sends a Local Binding Update message (LBU, Local Binding Update) to the PMAP to notify the PMAP to bind the LCoA and the RCo A. . PMAP After receiving the message, returns to the MN- local binding acknowledgment message (LBA, Local Binding Acknowledgement) ₀ Referring to FIG. 6, PAR MN is currently connected access router, corresponding to the service network PoS. The NAR corresponds to the target network PoS. This embodiment mainly includes the following steps:

Step 601: The MN sends, to the information server, a network prefix request that carries the MAP domain to which each neighbor network belongs, and each The MIH_Get_Information request message of the network prefix request of the neighbor network.

In this embodiment, the MN sends an MIH_Get_Information request message to the information server, where the message carries the network prefix request information of each neighbor network and the network prefix request information of the MAP domain to which each neighbor network belongs.

Step 602: The information server sends a MIH_Get_Information response message carrying the network prefix of the MAP domain to which the neighbor network belongs and the network prefix of each neighbor network to the MN.

Step 603 - Step 606 is the same as step 203 - step 206 in the method shown in Figure 2, and will not be repeated here. The terminal selects the target network according to the mobility management protocol information supported by each candidate network and the returned resource query result. After the target network is determined, it is further determined whether the network prefix of the MAP domain to which the target network belongs is different from that before the handover. If the MN indicates that the MN only switches within the MAP domain, the LCoA is configured according to the prefix of the selected target network.

Step 607: The MN sends a MIH MN HO Candidate Commit request message carrying the configured NLCoA information to the serving network.

After the target network PoS is selected, the MN sends a MIH_MN_HO_Candidate_Commit request message to the serving network PoS, where the message carries the configured LCoA information. In this embodiment, it is assumed that the target network is the candidate network 2.

Step 608: The service network PoS sends a network handover candidate execution request (MIH_Net_HO_Candidate_Commit request) message carrying the configured LCoA information to the target network PoS.

After receiving the message, the target network PoS extracts the LCoA information configured by the MN for duplicate address detection. If the address conflicts, the target network PoS re-configures the LCoA information for the MN.

Step 609: The target network PoS sends a network handover candidate execution response (MIH_Net_HO_Candidate_Commit response) message carrying the detected LCoA information to the serving network PoS.

Step 610: The serving network PoS sends a message of the terminal handover candidate execution response (MIH_MN_HO_Candidate_Commit response) carrying the detected LCoA information to the MN, and returns the result of the address detection to the MN.

After performing the link layer handover, the MN immediately performs network layer switching according to the LCoA information acquired in advance. In this embodiment, the switching of the network layer includes the MN sending a local binding update message (LBU) to the PMAP for binding update of the LCoA, and the PMAP returning the local binding update message (LBU) to the MN, and starting to establish the peer node. The network layer data channel between the MAP and the target network PoS, and the process of forwarding packets.

Step 611 - Step 614 is the same as step 211 - step 214 in the method shown in Figure 2, and will not be repeated here. In the embodiment of the present invention, the network prefix of each candidate network is carried by the MIH_N2N_HO_Query Resources response message returned by each candidate network, and the network prefix information of each candidate network is obtained.

In the embodiment of the present invention, the network prefix of the MAP domain to which each candidate network belongs may be obtained by using the MIH_N2N_HO Query Resources response message returned by each candidate network to obtain the network prefix of the MAP domain to which each candidate network belongs. Interest.

The method for performing the mobility management protocol negotiation between the MN and the network side in the first embodiment and the second embodiment is also applicable to the embodiment. The method in the embodiment of the present invention is also applicable to the process of triggering the handover on the network side.

In this embodiment, the network address configuration and the address conflict detection can be completed in advance by using the link layer switching message, thereby shortening the delay of the handover, thereby improving the user experience.

In addition, in this embodiment, the interaction between the service network PoS and the target network PoS is performed before the network layer is switched, and the target network can be notified in advance to establish the data channel of the link layer and the network layer at the same time, thereby reducing the handover to the new target network, and then sequentially The process of establishing the link layer data channel and the network layer data channel greatly reduces the data interruption time caused by the handover process.

Embodiment 4:

FIG. 7 is a flowchart of a method for implementing network handover according to a fourth embodiment of the present invention. This embodiment is a network switching process in which the MN triggers the Proxy Mobile IP (PMIP) protocol to implement global mobility management. The purpose of the PMIP protocol is to make the MN do not need to perform new IP address acquisition and duplicate address detection during the handover process. It only needs to set the MN's home address (HoA, Home Address) and the new proxy mobility anchor point (NPMA) on the HA. The address of the New Proxy Mobile Anchor) is bound to reduce handover delay and air interface signaling. According to the requirements of the PMIP protocol, in this embodiment, the network information such as the network prefix is not required to be configured in advance to configure the IP address in the new network, and only after the MN selects the 0-standard network according to the resource query result returned by each candidate network. The link layer switching message is used to send the HoA of the MN to the target network PoS. After receiving the HoA of the MN, the target network PoS is bound to update with the HA to establish a network layer data channel between the peer node HA and the peer node HA in advance. Thus, the network layer mobility management information in the link layer handover message is: HoA information of the MN. Referring to Figure 7, the service network PoS corresponds to the old proxy mobility anchor (PPMA) in the PMIP protocol, and the target network PoS corresponds to the PM in the PMIP protocol. This embodiment mainly includes the following steps:

Step 701 - Step 706 is the same as steps 201 - 206 in the method shown in Figure 2.

Step 707: 发 Send a message to the service network PoS to send a terminal to perform a MIH MN HO Candidate Commit request message.

After the target network PoS is selected, the MN sends a MIH_MN_HO_Candidate_Commit request message to the serving network PoS, where the message carries the HoA information of the MN. In this embodiment, it is assumed that the target network is the candidate network 2.

Step 708: The service network PoS sends a message of the network handover candidate execution request (MIH_Net_HO_Candidate_Commit request) carrying the HoA information of the MN to the target network PoS.

The serving network PoS forwards the drawn HoA information to the target network PoS by using the MIH_Net_HO Candidate Commit request message carrying the HoA information of the MN. Step 709: The target network PoS sends a Binding Update (BU) message to the HA.

In this embodiment, the care-of address of the MN is the IP address of the target network PoS.

Step 710: The HA sends a Binding Acknowledgement (BA) message to the target network PoS. In this embodiment, the HA returns a BA message to the target network PoS to respond, and starts to establish the network layer data channel of the HA and the target network PoS in advance.

Step 711: The target network PoS sends a MIH Net HO Candidate Commit response message to the service network PoS.

Step 712: The service network PoS sends a message of the MIH MN HO Candidate Commit response to the MN.

Step 713 - Step 716 Steps 211 - 214 in the method shown in Figure 2 are the same, and are not described here.

After the MN successfully switches to the target network, the data can be forwarded through the tunnel established in advance in steps 709-710.

In this embodiment, the interaction between the service network PoS and the target network PoS is performed before the handover, and the target network can be notified in advance to establish the data channel of the link layer and the network layer at the same time, and the link layer data channel is sequentially performed after switching to the new target network. The process of establishing a data channel with the network layer greatly reduces the data interruption time caused by the handover process. Embodiment 5:

FIG. 8 is a flowchart of a method for implementing network switching according to a fifth embodiment of the present invention. This embodiment is a network switching process in which the MN triggers the NetLMM protocol. The purpose of the NetLMM protocol is to prevent the MN from changing the IP address during the mobile mobility in the local mobility management domain, that is, the process of acquiring new IP addresses, detecting duplicate addresses, and registering NCoAs to the global mobility anchor point, thereby reducing handover delay and Air interface signaling.

Since both the service network and the target network support local mobility management, and within the same local mobility management domain, only the same local mobility anchor (LMA, Local Mobile Anchor) is used to manage the MN under different ARs under the LMA. The handover does not require notification of possible remote global mobility management anchors, such as network elements such as HA, but only through the conversion of data channels under the LMA to ensure that data for the MN can reach the new AR after handover. Therefore, in this embodiment, after the MN selects the target network and the service network notifies the target network that the MN is ready to start the handover, the target network PoS and the LMA perform location registration without notifying the remote mobility management anchor, and reducing signaling. The transmission time is established in advance to establish a tunnel between the target network and the peer node LMA. In this embodiment, the network layer mobility management information in the link layer switching message is: location registration information to the LMA. Referring to Figure 8, the service network PoS corresponds to The old mobile access gateway (PMAG) in the NetLMM protocol, the target network PoS corresponds to the new mobile access gateway (NMAG, New Mobile Access Gateway), and specifically includes the following steps: Step 801 - Step 806 and FIG. Steps 201 - 206 of the illustrated method are the same.

Step 807: The MN sends a message to the service network PoS to send a MIH MN HO Candidate Commit request message.

After the target network PoS is selected, the MN sends a MIH_MN_HO_Candidate_Commit request message to the serving network PoS. In this embodiment, it is assumed that the target network is the candidate network 2.

Step 808: The service network PoS sends a MIH Net HO Candidate Commit request message to the target network PoS.

Step 809: The target network PoS sends a Location Registration message to the LMA.

After receiving the message, the target network PoS sends a location registration message to the LMA, where the message includes location registration information such as the target network identifier, the MN identity, the network prefix of the target network, and the LMA identity, and is used to notify the LMA that an established state has been created in advance. The MN is ready to request the NetLMM service.

Step 810: The LMA sends an Acknowledge message to the target network PoS.

In this embodiment, a handover state is created for a data packet addressed to the MN based on the network prefix of the target network.

Step 811: The target network PoS sends a MIH_Net HO Candidate Commit response message to the service network PoS.

Step 812: The service network PoS sends a MIH MN HO Candidate Commit response message to the MN.

Step 813-step 816 is the same as step 211-step 214, and will not be repeated here. After the MN successfully switches to the target network, the data is forwarded through the network layer data channel established in advance in steps 809-810.

This embodiment is also applicable to the process of network handover in which the PMIP protocol implements local local mobility management. In this embodiment, the interaction between the service network PoS and the target network PoS is performed before the handover, and the target network can be notified in advance to establish the data channel of the link layer and the network layer at the same time, and the link layer data channel is sequentially performed after switching to the new target network. The process of establishing a data channel with the network layer greatly reduces the data interruption time caused by the handover process. Embodiment 6

FIG. 9 is a schematic structural diagram of a wireless communication system for implementing network handover according to a sixth embodiment of the present invention, where the system includes: a terminal 910, a target network PoS920, and a service network PoS930; The terminal 910 receives a link layer handover message that carries the network layer mobility management information sent by the service network PoS930 or the target network PoS920, and performs network layer mobility by using network layer mobility management information carried in the link layer handover message. Management, and when the terminal 910 triggers the handover, the network layer mobility management information carried in the link layer handover message is used to determine the target network PoS920 and perform network layer mobility management;

The service network PoS930 receives the link layer handover message sent by the terminal 910 or the target network PoS 920 and carries the network layer mobility management information, and uses the network layer mobility management information carried in the link layer handover message to perform network layer mobility. Sex management, and when triggered on the network side, determine the target network and perform network layer mobility management by using the network layer mobility management information of the candidate network carried in the link layer switching message;

The target network PoS920 receives the link layer handover message from the terminal 910 or the service network PoS930, and performs network layer mobility management.

The terminal 910 includes: a receiving unit 911 and an executing unit 912;

The receiving unit 911 receives the link layer handover message from the service network 930 or the target network 920 and carries the network layer mobility management information, and inputs the received link layer handover message to the execution unit 912;

The executing unit 912 performs the network layer mobility management protocol negotiation, acquires the network information of the target network in advance, and triggers the handover at the terminal 910 by using the network layer mobility management information carried in the link layer switching message input by the receiving unit 911. When the network layer mobility management information carried in the link layer switching message is used, the target network of the handover is determined.

The service network PoS930 includes a service network PoS receiving unit 931 and a service network PoS executing unit 932. The serving network PoS receiving unit 931 receives a link layer switching message that is sent from the terminal 910 or the target network 920 and carries network layer mobility management information. And input the received link layer switch message to the service network PoS execution unit 932;

The service network PoS execution unit 932 performs network layer mobility management protocol negotiation, and acquires network information of the target network in advance by using network layer mobility management information carried in the link layer handover message input by the service network PoS receiving unit 931. The network layer data channel between the service network 930 and the target network 920 is established in advance, and when the network side triggers the handover, the network layer mobility management information of the candidate network carried in the link layer handover message is used to determine the target network of the handover.

The target network PoS 920 includes a target network PoS receiving unit 921 and a target network PoS executing unit 922. The target network PoS receiving unit 921 receives a link layer switching message that carries network layer mobility management information from the terminal 910 or the serving network 930. And input the received link layer switch message to the target network PoS execution unit 922;

The target network PoS execution unit 922 cuts the link layer carried in the target network PoS receiving unit 921. The network layer mobility management information in the message is exchanged, the new care-of address assignment and address conflict detection under the target network are performed, or the network layer data channel between the service network and the target network or between the peer node and the target network is established in advance.

The method and system for implementing network switching provided by the foregoing embodiments are applicable not only to implementing network handover in an IP mobility management domain, but also to multiple radio access technologies and single radio access technologies, and if multiple radio access technologies are used, FIG. 10 is a schematic diagram of a mobility management architecture in a network handover process according to an embodiment of the present invention. The IP mobility management domain function may include route management and IP layer handover execution; the multiple radio resource management domain function includes a multi-radio resource management function (MRRM), an IP mobility management domain, and a multi-radio resource management domain. The user-independent layer of the media-independent switching layer mainly includes context information transfer, handover management, tool selection, and trigger management. The lower layer is a radio access technology (RAT, Radio Access Technology) of various standards. Access network link layer protocol. If the single radio access technology is targeted, the multi-radio resource management domain in FIG. 10 is degraded to the radio resource management domain of the specific radio access system.

The method for implementing network handover and the wireless communication system provided by the embodiments of the present invention carry network layer mobility management information in a link switch message, and can use a link layer handover message carrying network layer mobility management information in the network. Corresponding mobility management is performed in advance before layer switching, which can reduce handover delay and improve network handover performance.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for implementing network switching, the method comprising:

Network layer mobility management is performed using network layer mobility management information carried in the link layer handover message.

2. The method for implementing network switching according to claim 1, wherein the performing network layer mobility management comprises any one or any combination of the following:

Conduct network layer mobility management protocol negotiation, obtain network information of target network in advance, perform new care-of address assignment and address conflict detection under target network, establish network layer data channel between service network and target network in advance, and establish peer in advance Network layer data channel between the node and the target network.

The method for implementing network handover according to claim 2, wherein the network layer mobility management information comprises: a network layer mobility management protocol supported by a neighbor network or a candidate network;

The method for performing the negotiation of the network layer mobility management protocol includes: obtaining a network layer supported by each neighbor network or candidate network by parsing a link layer handover message carrying network layer mobility management protocol information supported by the neighbor network or the candidate network The mobility management protocol determines the target network to be switched from the neighbor network that supports the same network layer protocol as the terminal, determines the candidate network to be switched, or selects a candidate network that supports the same network layer protocol from the terminal.

The method for implementing network handover according to claim 2, wherein the network layer mobility management information comprises: a mobility management protocol supported by the candidate network, or network prefix information of the candidate network, or a candidate network. The network prefix information of the mobile anchor MAP domain, or the new care-of address information of the terminal under the target network; the method for obtaining the network information of the target network is: parsing the link layer handover message carrying the candidate network mobility management information Obtaining network layer mobility management information of each candidate network, and after determining the target network of the handover, extracting network layer mobility management information of the target network from the acquired network layer mobility management information of each candidate network, as a target Network information of the network.

The method for implementing network switching according to claim 2, wherein when the network layer mobility management protocol is a fast mobile IP protocol, the network layer mobility management information includes: network prefix information of the target network; The method for performing the assignment of the new care-of address and the address conflict detection in the target network includes: performing the assignment of the care-of address and the address conflict detection under the target network by analyzing the link layer handover message carrying the network prefix information of the target network.

The method for implementing network switching according to claim 2, wherein when the network layer mobility management protocol is a fast mobile IP protocol, the network layer mobility management information includes: NCoA information of the terminal; The method for establishing a network layer data channel between the service network and the target network in advance includes: performing a binding update of the NCoA by parsing the link layer switching message carrying the NCoA information, and establishing a service network PoS and the target network PoS in advance Network layer data channel.

The method for implementing network switching according to claim 2, wherein when the network layer mobility management protocol is a fast hierarchical mobile IP protocol, the network layer mobility management information includes: a MAP domain to which the target network belongs Network prefix information and network prefix information of the target network;

The method for performing the allocation of the new care-of address and the address conflict detection in the target network includes: obtaining the target by parsing the link layer switching message carrying the network prefix information of the target network and the network prefix information of the mobile anchor MAP domain to which the target network belongs The network prefix information of the network and the network prefix information of the MAP domain to which the target network belongs are used to perform allocation and address conflict detection of the new link care-of address LCoA and/or the global forwarding address RCoA under the target network.

The method for implementing network switching according to claim 2, wherein, when the network layer mobility management protocol is a fast hierarchical mobile IP protocol, the network layer mobility management information includes: LCoA information of the terminal; The method for establishing a network layer data channel between the peer node and the target network in advance includes: performing a binding update of the LCoA in the MAP domain by parsing the link layer switching message carrying the NLCoA information, and establishing an MAP between the MAP and the target network PoS in advance Network layer data channel.

The method for implementing network switching according to claim 2, wherein when the network layer mobility management protocol is a fast proxy mobile IP protocol, the network layer mobility management information includes: a home address HoA information of the terminal; The method for establishing a network layer data channel between a peer node and a target network in advance includes: after determining the target network of the handover, performing a link layer handover message carrying the home address HoA information of the terminal, and performing HoA on the home agent HA The binding update updates the network layer data channel between the target network PoS and HA in advance.

10. The method for implementing network handover according to claim 2, wherein the network layer mobility management protocol at the network layer implements fast local local mobility management for a fast proxy mobile IP protocol or a network-based local mobility management protocol. The method for establishing a network layer data channel between the peer node and the target network includes: after determining the target network of the handover, by analyzing the link layer handover message carrying the location registration information, the target network PoS and the local mobility anchor point The LMA performs location registration to establish a network layer data channel between the target network PoS and the LMA in advance.

The method for implementing network handover according to any one of claims 1 to 10, wherein the link layer handover message includes: link layer handover message defined in 3GPP, 3GPP2, and IEEE 802 series standards. , or media-independent switching MIH layer switching messages in the 802.21 protocol.

12. A wireless communication system, the system comprising: a terminal, a target network PoS, a service network PoS;

The terminal is configured to receive a bearer network layer mobility management sent from a service network PoS or a target network PoS The link layer switching message of the information uses the network layer mobility management information carried in the link layer switching message to perform network layer mobility management, and uses the network layer carried in the link layer switching message when the handover is triggered. Mobility management information, identifying the target network and performing network layer mobility management;

The service network PoS is configured to receive a link layer handover message that carries network layer mobility management information sent by the terminal or the target network PoS, and uses the network layer mobility management information carried in the link layer handover message to perform network Layer mobility management, and when the handover is triggered, the network layer mobility management information of the candidate network carried in the link layer handover message is used to determine the target network and perform network layer mobility management;

The target network PoS is configured to receive a link layer handover message from a terminal or a service network PoS, and perform network layer mobility management.

The wireless communication system according to claim 12, wherein the terminal comprises: a receiving unit and an executing unit;

The receiving unit is configured to receive a link layer handover message that carries network layer mobility management information sent by the serving network PoS or the target network PoS, and input the received link layer switching message to the execution unit;

The executing unit is configured to perform network layer mobility management protocol negotiation, obtain network information of the target network in advance, and use network layer mobility management information carried in the link layer switching message input by the receiving unit, and When the handover is triggered, the network layer mobility management information carried in the link layer handover message is used to determine the target network to be handed over.

The wireless communication system according to claim 12, wherein the service network PoS comprises a service network PoS receiving unit and a service network PoS executing unit;

The service network PoS receiving unit is configured to receive a link layer handover message that carries network layer mobility management information sent by the terminal or the target network PoS, and input the received link layer handover message to the service network PoS for execution. Unit

The service network PoS execution unit is configured to perform network layer mobility management protocol negotiation and acquire a target network network in advance by using network layer mobility management information carried in a link layer handover message input by a serving network PoS receiving unit. The information or the network layer data channel between the service network PoS and the target network PoS is established in advance, and when the handover is triggered, the network layer mobility management information of the candidate network carried in the link layer handover message is used to determine the target network of the handover.

The wireless communication system according to claim 12, wherein the target network PoS comprises a target network PoS receiving unit and a target network PoS executing unit;

The target network PoS receiving unit is configured to receive a link layer handover message that carries network layer mobility management information sent by the terminal or the service network PoS, and input the received link layer handover message to the target network PoS for execution. unit; The target network PoS execution unit is configured to perform network address mobility management information in the link layer handover message input by the target network PoS receiving unit, and perform new assignment address assignment and address conflict detection under the target network, or Establish a network layer data channel between the service network PoS and the target network PoS, or between the peer node and the target network PoS.