JP4461155B2 - Communication system, control apparatus, router and communication method using network-based IP mobility protocol - Google Patents

Description

  The present invention relates to a communication technique using a network-based IP mobility protocol.

  In recent years, research and development of mobility support in the IP layer such as Mobile IPv6 (Internet Protocol version 6) has been active. Mobile IP is a network layer protocol that is the third layer in the OSI (Open Systems Interconnection) basic reference model established by ISO (International Organization for Standardization). This is a technology that conceals communication interruptions and continues communication.

  TCP / IP (Transmission Control Protocol / Internet Protocol), which is a communication protocol generally used in the current Internet, means an IP address as an identifier, and also a position on a network. For this reason, when a node connected to a certain network is changed to another network, the IP address changes, and the session cannot be continued.

  Therefore, Mobile IP assigns a unique address to a node and replaces it with the IP address actually used in the TCP / IP stack. Provides a mechanism that makes it appear as if it is communicating (for example, see Non-Patent Document 1).

  The Mobile IP includes a mobile node (Mobile Node, mobile terminal, hereinafter referred to as “MN”), a home agent (Home Agent, hereinafter referred to as “HA”), a correspondent node (Correspondent Node, an opposite node, hereinafter, “CN”). ”)).

  The MN always has an invariable address called a home address (hereinafter referred to as “HoA”), and the node that manages the address is the HA. When the MN connects to a network other than the home link, which is a link of the HA, an address that is actually used for communication called a care-of address (care-of-address, hereinafter referred to as “CoA”) For example, it is obtained by router advertisement (Router Advertisement, hereinafter referred to as “RA”) with stateless address automatic setting or DHCP (Dynamic Host Configuration Protocol) v6 with stateful address automatic setting. The MN notifies the HA of the CoA obtained here with a message of a registration request (Binding Update, hereinafter referred to as “BU”).

  As a result, when a node (= CN) that wants to communicate with the MN transmits a packet to the HoA, the HoA is a link address managed by the HA, and therefore reaches the HA once. At that time, the HA transfers to the CoA associated with the HoA. As a result, the MN can always communicate with HoA. In the MN, an application operating on the MN always uses the IP address called HoA for communication.

  CoA is used as the source address or destination address of the actual IPv6 packet. Further, in order to conceal the movement from the upper application, techniques such as IPv6 in IPv6 encapsulation and mobility header are used. As a result, HoA is notified to the application, and the IPv6 address (CoA) actually used is concealed.

  However, since Mobile IPv6 cannot perform high-speed handover, FM IPv6 (Fast Hands for Mobile IPv6) has been proposed (see, for example, Non-Patent Document 2).

  FIG. 11 is a sequence diagram illustrating a processing procedure in FMIPv6. FIG. 11 will be described as an example.

  RtSolPr (Router Solicitation for Proxy Advertisement, hereinafter referred to as “RtSolPr”) of S301 in FIG. 11 is a message sent by a host used in normal IPv6 to generate a router advertisement to the router. Router solicitation (router solicitation) is extended for FMIPv6.

  In step S302, the PAR (Previous Access Router, communication access router, hereinafter referred to as “PAR”) that has received this RtSolPr from the MN sends the PrRtAdv (Proxy Router Advertisement, proxy router advertisement, hereinafter referred to as “PrRtAdv”) to the MN. Send to. PrRtAdv is an extension of the RA used for normal IPv6 for FMIPv6.

  The MN that has received this PrRtAdv transmits an FBU (Fast Binding Update), which is a binding update for fast handover, to the PAR in S303. This FBU includes NCoA (New Care of Address, new CoA, hereinafter referred to as “NCoA”) information, and NCoA is NAR (New Access Router, destination access router, hereinafter referred to as “NAR”). Since the address belongs to the link, the PAR can transfer the packet to the NAR.

  The PAR that has received the FBU transmits an HI (Handover Initiate, hereinafter referred to as “HI”) to initialize the MN switching and handover to the NAR in S304.

  The NAR transmits HAck (Handover Acknowledge, hereinafter referred to as “HAck”) to the PAR as confirmation for the HI in S305, and packet transfer between the PAR and the NAR is started in S306.

  When the MN completes the movement and completes the movement under the NAR (same link), the MN transmits an FNA (Fast Neighbor Advertisement, hereinafter referred to as “FNA”) to the NAR in S307. This is to notify the NAR that the movement has been completed. As a result, in S308, the NAR starts delivering a packet to the MN.

  MIPv6 and FMIPv6 are called host-based mobility protocols because they control mobility based on the MN. On the other hand, a network-based IP mobility protocol that performs mobility control on the network side and enables the MN to move without installing a special protocol for movement has been further proposed by IETF (Internet Engineering Task Force). (For example, refer nonpatent literature 3).

  This eliminates the need for the MN to handle CoA, eliminates packet encapsulation by the MN, and eliminates signaling for movement by the MN. The handover procedure of the first network-based IP mobility protocol will be described with reference to FIG.

  First, after the movement, in S401, the MN moves to a router or mobile access gateway (Mobile Access Gateway, hereinafter referred to as “MAG”) of the link of the movement destination indicated as “NewMAG” in FIG. A router configuration, a router solicitation (hereinafter referred to as “RS”) or a network configuration request message such as DHCP Request is transmitted.

MAG is a router that relays between a MN that has moved to the link and a root router, which is a control device that controls IP Mobility, and a local mobility anchor (hereinafter referred to as “LMA”). It is.
The LMA controls a plurality of MAGs connected via a network. The LMA manages the identifiers and IP addresses of the MN and MAG in the storage unit.
The MAG also manages the identifiers and IP addresses of the MN and LMA in the storage unit. Information managed by these MAGs can be acquired by communicating with the LMA.
Between MAG and LMA, packets are IPv6 in IPv6 encapsulated, and a header is attached with reference to information managed in the storage unit, so that tunneling can be performed and routing can be performed correctly.
In the network as described above, it is assumed that the MN transmits, for example, an RS here to the MAG of the same link at the movement destination.

  When MAG (NewMAG) receives RS from MN, it transmits location registration (position registration request) to LMA in S402.

  When the LMA receives the location registration, it detects that it is a handover, transmits a routing setup to the MAG (NewMAG) in S403, and sets a tunnel path between the MAG (NewMAG) and the LMA.

  Here, the setting of the tunnel path means that the LMA encapsulates the packet for the MN and transmits the destination as the MAG, and the received MAG is set to remove the capsule and forward it to the MN.

  The MAG (NewMAG) that has received this routing setup transmits a confirmation routing setup Ack (Acknowledgement) to the LMA in S404.

  Further, the LMA that has received the location registration from the MAG (NewMAG) transmits a confirmation location registration Ack to the MAG (NewMAG) in S405.

  In step S406, the MAG (NewMAG) transmits RA to the MN, and the MN performs address configuration (address setting).

  Thereafter, in S407, the MN uses DAD (Duplicate Address Detection, hereinafter referred to as “DAD”) for NA (Neighbor Advertisement, hereinafter referred to as “NA”) to MAG (NewMAG). Confirm that the address is single and complete the address configuration. Further, the MAG (NewMAG) transmits the MN address setup to the LMA in S408, and in S409, the LMA transmits the MN address setup Ack to the MAG (NewMAG).

  As a result of completion of the LMA-MAG tunnel path setting and the MN address configuration, the packet can reach the MN. This is the handover method of the network-based mobility protocol. That is, since the packet addressed to the MN is sent via the LMA, the tunnel can be routed to the MN by completing the tunnel between the LMA and the MAG.

  There is also a Proxy Mobile IP method using a network-based IP mobility protocol in which an MAG performs an MN proxy (proxy) function in Mobile IP using an AAA (Authentication Authorization Accounting) server that performs authentication and the like. Proposed. (For example, refer nonpatent literature 4).

  A handover procedure according to the Proxy Mobile IP scheme of the second network-based IP mobility protocol will be described with reference to the sequence diagram of FIG.

  First, in S501, after moving, the MN transmits authentication information including the MN-ID that is its own ID to the MAG (NewMAG).

  In step S502, the MAG (NewMAG) that has received the authentication information from the MN transmits the authentication information including the MN-ID to the AAA server that is the authentication server for authentication.

  The AAA server that has received the authentication information from the MAG (NewMAG) checks the validity of the MN in S503, and returns a policy profile if it is determined to be valid. This policy profile includes MN address configuration information such as information such as a home network prefix and a configuration method (stateless setting or stateful setting).

  In the MAG (NewMAG) that has received the policy profile including the address configuration information from the AAA server, the RA can be transmitted to the MN. In S504, the RA is transmitted to the MN.

  The MN that has received the RA from the MAG (NewMAG) configures an address and performs NA and DAD in S505. This step may be omitted.

When the MAG (NewMAG) transmits the RA, in order to generate a tunnel with the LMA, a proxy registration request (Proxy Binding Update) is transmitted to the LMA in S506.
This message includes the MN-ID, the home prefix of the MN, and the like.

  The LMA that has received the Proxy Binding Update returns a Proxy Binding Update Ack to the MAG (NewMAG) in S507.

  In this way, a bidirectional tunnel is generated between the LMA and MAG, and routing to the MN becomes possible.

  Further, as a technique for compressing the header of IP / UDP / RTP (Internet Protocol / User Datagram Protocol / Real-time Transport Protocol), robust header compression (hereinafter referred to as “ROHC”) is known. . (For example, refer nonpatent literature 5).

  In this ROHC, a CID (Context ID), which is an identification ID notified at initialization, is associated with a predictable header field, and the information is shared by the compressor that compresses the data and the decompressor that restores the compressed data, The compressor sends a CID instead of the header, and the decompressor restores the header from the CID.

  The predictable header field also includes information on the source IP address indicating the transmission source and the destination IP address indicating the transmission destination.

  Furthermore, by assigning sequence numbers by W-LSB (Window-Based Last-Significant Bit), other fields can be predicted, and robustness against packet loss is also provided.

  ROHC has a state and a mode. The state adjusts the amount of compression according to the state of the link in three stages: full header / difference / maximum compressed header. The mode is selected from three types of feedback timing by the decompressor: no feedback, feedback if there is a problem, and always feedback.

  By selecting this state and mode according to the link state and W-LSB, ROHC provides high compression performance and high robustness.

  Also, a header compression context rearrangement method is disclosed (see, for example, Patent Document 1).

According to the invention, the old serving support node (SGSN) forwards the context on header compression to the new SGSN and reuses it at the new SGSN.
Special table 2004-517580 gazette Request for Comments (RFC) 3775, “Mobility Support in IPv6” Request for Comments (RFC) 4068, “Fast Handovers for Mobile IPv6” Internet Draft “draft-gearetta-netlmm-dt-protocol” Internet Draft “draft-sgandave-mip6-proxymip6” Request for Comments (RFC) 3095, “RObust Header Compression (ROHC): Framework and four profiles: RTP, UDP, ESP, and uncompressed”

However, it is difficult to use this ROHC in the network-based IP mobility protocol.
The main purpose of header compression in this way is to save the bandwidth of the last one hop (in many cases, a radio link), which is the narrowest band. Otherwise, the effect is small, and the effect is small unless the compressor of the packet from the MN is also the MN.

  In other words, the decompressor for packets destined for the MN should be the MN. At this time, the compressor is LMA or MAG. Here, if compression is performed with LMA, the MAG through which the packet arrives from the LMA has no IP address information of the MN when decapsulating the packet, so it is not known to which MN the packet should be delivered. End up.

  In addition, when transmitting a packet from the MN, it is impossible to determine which MN the packet sent via the MAG has come from, and therefore cannot be decompressed by the LMA.

  Also, if compression is performed by MAG, the new MAG does not have a state after handover, so it must be started again from the state creation phase, and the effect of header compression is diminished. That is, it is difficult to perform header compression efficiently in either method.

  These are common problems in the first and second network-based IP mobility protocols.

  Even if the technique of Patent Document 1 is to be used, the old MAG cannot be used because it does not know the address of the new MAG.

  The present invention has been made in order to solve the above-described problems. The purpose of the present invention is to narrow down the MN or MAG as a compressor and a decompressor even when the MN moves in the network-based IP mobility protocol. To provide a communication system, a control device, a router, and a communication method using a network-based IP mobility protocol that can save the last one-hop bandwidth.

In view of such a situation, the communication system using the network-based IP mobility protocol according to the first invention uses the network-based IP mobility protocol, and data is transmitted from routers belonging to the same link by addresses uniquely assigned to mobile terminals. Is a communication system that switches communication under the control of a control device when the mobile terminal moves to another network.
The router in the destination network of the mobile terminal receives a notification including the identifier of the mobile terminal from the mobile terminal, and notifies the control device including the identifier of the mobile terminal and the identifier or IP address of the router. The control device transmits a header compression information transfer instruction notification to the header of the mobile terminal of the mobile terminal so as to transfer header compression information from the source router to the destination router. Features.

  In the communication system using the network-based IP mobility protocol according to the second invention, the control device transmits the header compression information transfer instruction notification to the router that is the source of the mobile terminal and the source of the source A buffer transfer instruction notification is transmitted from the router so as to transfer the data addressed to the mobile terminal to the destination router.

  A communication system using the network-based IP mobility protocol according to the third invention is characterized in that the control device synthesizes and transmits the header compression information transfer instruction notification and the buffer transfer instruction notification.

According to a fourth aspect of the present invention, there is provided a control apparatus using a network-based IP mobility protocol, wherein a mobile terminal performs communication by transmitting and receiving data from a router belonging to the same link using a uniquely assigned address. A control device that performs control to switch communication when a terminal moves to another network,
Communication means for receiving a notification including the identifier of the mobile terminal and the identifier or IP address of the router from the router in the destination network of the mobile terminal, and holding communication information regarding the router and the mobile terminal performing relay The storage means, and the mobile terminal's identifier included in the notification from the router, the communication information of the mobile terminal is referred to the storage means, and the information on the destination router and the data transfer between the routers is updated. And generating a header compressed information transfer instruction notification including the identifier of the mobile terminal and the identifier or IP address of the destination router instructing the source router to transfer header compressed information to the destination router. Control means, and the communication means notifies the move source router of the header compressed information transfer instruction notification. And transmitting.

  The control device according to a fifth aspect of the invention is the control device, wherein the control means instructs the mobile terminal to transfer data addressed to the mobile terminal from the source router to the destination router and the destination A buffer transfer instruction notification including an identifier or IP address of a router is generated, and the communication unit transmits the header compressed information transfer instruction notification and the buffer transfer instruction notification to the source router. And

  In the control device according to a sixth aspect of the invention, the communication means synthesizes and transmits the header compression information transfer instruction notification and the buffer transfer instruction notification to the source router.

A router according to a seventh aspect of the invention is a router that uses a network-based IP mobility protocol and transmits / receives data to / from a mobile terminal belonging to the same link that performs communication using a uniquely assigned address under the control of a control device. And
Storage means for storing header compression information when transmitting data to the mobile terminal, an identifier of the mobile terminal that instructs transfer of the header compression information from the control device to the router to which the mobile terminal has moved, and A communication unit that receives a header compression information transfer instruction notification including an identifier or IP address of a destination router; and a control unit that transfers the header compression information to the destination router by the transfer instruction notification. Features.

  According to an eighth aspect of the present invention, there is provided the router according to the eighth aspect, wherein the communication means instructs the transfer of data addressed to the mobile terminal from the control device to the destination router of the mobile terminal, and the destination router. And receiving the buffer transfer instruction notification including the identifier or the IP address, and the control means transmits the header compression information and transfers the data addressed to the mobile terminal.

A communication method according to a ninth invention uses a network-based IP mobility protocol, and causes a mobile terminal to transmit and receive data from a router belonging to the same link using a uniquely assigned address. When moving to a network, a communication method for causing a control device to perform control for switching communication of the mobile terminal,
Receiving the notification from the mobile terminal to detect the movement of the mobile terminal to the same link to the router in the destination network of the mobile terminal, and notifying the control device of the movement of the mobile terminal And a step of causing the control device to transmit a header compression information transfer instruction notification instructing transfer of header compression information to the destination router to the source router. .

  The communication method according to a tenth aspect of the invention causes the control device to execute a step of transmitting a buffer transfer instruction notification instructing transfer of data addressed to the mobile terminal to the destination router to the source router. It is characterized by that.

  According to the present invention, in the network-based IP mobility protocol, when a mobile terminal (MN) moves to another network, the control device (LMA) moves to the source router (MAG) of the mobile terminal. By transmitting information related to the destination router (MAG), the source router transmits header compression information (ROHC information) when transmitting / receiving data to / from the mobile terminal to the destination router. Holds header compression information, so that handover can be performed while maintaining the ROHC state.

  In addition, the control device sends information on the destination router to the source router, and the source router moves by creating a tunnel when sending header compression information to the destination router. Data addressed to the mobile terminal in the buffer of the original router can be transferred to the destination router, and fast handover can be supported at the same time.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram showing a schematic configuration of a network in the present embodiment.
FIG. 2 is a sequence diagram illustrating a processing procedure in the present embodiment.
FIG. 3 is a block diagram showing the configuration of the MAG in this embodiment.
FIG. 4 is a block diagram showing the configuration of the LMA in this embodiment.

As shown in FIG. 1, initially, MN1 is under MAGa2. Further, it is assumed that MAGa2, MAGb3, and MAGc4 are arranged under the same LMA5. It is assumed that the MN 1 communicates with the CNb 9 via the Internet 7 and the router (Router) 8 with the CNa 6 arranged in the link of the MAGc 4 under the same LMA 5.
Further, MAGa2, MAGb3, and MAGc4 are connected to AAA server 10 that performs authentication and the like in the Proxy Mobile IP system.
It is assumed that MN1 moves from MAGa2 to MAGb3 under the movement.
In the present embodiment, description will be made on the assumption that handover is performed by the Proxy Mobile IP system.

The MAG in FIG. 3 and the LMA in FIG. 4 will be described below.
As shown in FIG. 3, the MAGs 2, 3, and 4 communicate with the LMA 5 and the AAA server 10 and communicate with the MN 1 wirelessly with a communication means 11 that performs wired communication such as a LAN (Local Area Network) or the Internet. Wireless communication means 12 for performing, network-based IP mobility protocol processing unit 13 for performing control related to network-based IP mobility protocol, storage unit 14 serving as a database unit, temporary storage unit 15 capable of being temporarily stored, compression -It is comprised including the expansion | extension process part 16.

  As shown in FIG. 4, the LMA 5 also includes a communication unit 17, a network-based IP mobility protocol processing unit 18, and a storage unit 19.

  Next, the flow of processing in this embodiment will be described with reference to the sequence diagram of FIG.

  First, in S101, MN1 transmits authentication information including at least the MN-ID that is the identifier of MN1 to MAGb3 or a link local multicast address after moving under the control of MAGb3.

  The network-based IP mobility protocol processing unit 13 of the MAGb 3 that has received the authentication information from the wireless communication unit 12 stores the MN-ID in the storage unit 14 and at least the MN-ID, the MAGb 3 identifier, and the MAGb-ID in S102. Authentication information is generated and transmitted from the communication means 11 to the AAA server 10.

  Upon receiving the authentication information, the AAA server 10 confirms the validity of the MN's network participation in S103, and if OK, the MN-ID is used as a key from the database of the AAA server 10 itself or another node on the network. Address information is transmitted, and the authentication OK including the address information is transmitted to MAGb3.

  Next, the network-based IP mobility protocol processing unit 13 of the MAGb 3 that has received the authentication OK from the communication unit 11 extracts the address information of the MN included in the authentication OK, and transmits the RA to the MN 1 from the radio communication unit 12.

  In step S105, the MN 1 that has received the RA from the MAGb 3 transmits the NA to the link in the DAD procedure.

  The MAGb3 network-based IP mobility protocol processing unit 13 receives the NA from the MN1, and then, in S106, the proxy binding update including the address information such as the IP address prefix of the MN1 or the IP address of the MN1 and the IP address of the MAGb3. Is transmitted from the communication means 11 to the LMA 5. The generation and transmission processing of Proxy Binding Update is performed after NA reception, but can be executed after receiving the authentication OK, and the order may be changed.

  Next, the network-based IP mobility protocol processing unit 18 of the LMA 5 that receives the Proxy Binding Update from the MAGb 3 via the communication unit 17 associates the address information of the MN 1 included in the Proxy Binding Update with the IP address of the MAGb 3 and stores the storage unit 19. The packet that matches the address information of MN1 is encapsulated with the IP address of MAGb3, and is set to be transmitted to MAGb3. Further, when the above setting is completed, the network-based IP mobility protocol processing unit 18 transmits a Proxy Binding Update Ack from the communication unit 17 to MAGb 3 in S107.

  The network-based IP mobility protocol processing unit 13 of the MAGb 3 that has received the Proxy Binding Update Ack from the LMA 5 via the communication means 11 performs a setting for encapsulating the packet from the MN 1 with the IP address of the LMA 5 and transmitting it to the LMA 5. Bidirectional encapsulation is completed by the above-described encapsulation setting in LMA5 and the encapsulation setting in MAGb3, and LMA-MAG tunneling is generated.

  The network-based IP mobility protocol processing unit 18 of the LMA 5 that has transmitted the Proxy Binding Update Ack to the MAGb 3 from the communication means 17 at S108, at least for the MAGa 2, the MAGb 3 identifier, the MAGb-ID or the MAGb 3 IP address and the MN A message for instructing transfer of header compression information including the identifier and MN-ID, and a header compression information transfer instruction are transmitted.

FIG. 5 is a diagram illustrating a configuration example of header compression information (ROHC information) held in the storage unit 14 of MAGb3.
FIG. 5A is an example of data indicating the state and mode in ROHC, FIG. 5B is an example of data storing a ROHC context, and FIG. 5C is a data storing sequence numbers and the like.

  Upon receiving the header compression information transfer instruction from the LMA 5, the MAGa2 network-based IP mobility protocol processing unit 13 in S109, for example, header compression information regarding a packet addressed to the MN1 address identified from the MN-ID as shown in FIG. Is received from the MAGb-ID and transferred to the IP address of MAGb3.

  This header compression information is necessary for ROHC and includes important information for mapping between the ROHC header and the uncompressed header. This information may be information such as the current mode, status, CID, W-LSB parameter, source address, destination address, source port, destination port, MN-ID, LMA-ID, and the like. At this time, MAGa2 erases the header compressed information related to MN1 from the storage unit 14.

  The network-based IP mobility protocol processing unit 13 of the MAGb 3 that has received the header compression information from the MAGa 2 stores the header compression information in the storage unit 14.

  Thereafter, after S110, the network-based IP mobility protocol processing unit 13 of the MAGb 3 outputs the packet to the compression / decompression processing unit 16, and the compression / decompression processing unit 16 stores the compressed information as shown in FIG. Based on the above, the IP / UDP / RTP header is compressed, and the network-based IP mobility protocol processing unit 13 starts delivery of packets from the wireless communication unit 12 to the MN1.

  In addition, when the header-compressed packet is received from the MN 1 via the wireless communication unit 12, the network-based IP mobility protocol processing unit 13 of the MAGb 3 outputs the packet to the compression / decompression processing unit 16, The decompression processing unit 16 can decompress the header of the packet and transfer it to the LMA 5.

  By adopting such a configuration, the MN1 moves and the link to which the MN1 belongs changes from MAGa2 to MAGb3, so that the compressor / uplink (from the communication partner to the MN) packet (from the communication partner to the communication partner) The header can be compressed and expanded even if the packet decompressor is changed.

  In this embodiment, the Proxy Mobile IP method has been described. However, the authentication procedure by the AAA server is omitted, and the present invention is applied to the first network-based IP mobility protocol method described in the prior art. However, the same effect can be obtained.

[Second Embodiment]
FIG. 6 is a diagram showing a schematic configuration of the network in the present embodiment.
FIG. 7 is a sequence diagram showing a processing procedure in the present embodiment.

  As shown in FIG. 6, initially, MNa 21 is under MAGa 22. As the MNa 21 moves, it is assumed that the MNa 21 has moved from under the MAGa 22 to under the MAGb 24 where the MNb 23 already exists. At this time, the movement of the MNa 21 is controlled by the LMAa 25, and the movement control of the MNb 23 is performed by the LMAb 26.

Next, the flow of processing in this embodiment will be described with reference to the sequence diagram of FIG.
First, in S201, the MNa 21 transmits a message including at least an MNa-ID that is an identifier of the MNa 21 to the MAGb 24 or a link local multicast address, and an ID and an LMAa-ID of the LMAa 25 that is an LMA in charge of its own mobility control. To do.

  The network-based IP mobility protocol processing unit 13 of the MAGb 24 that has received the message from the MNa 21 transmits a location registration including at least the MNa-ID and the MAGb-ID that is the identifier of the MAGb 24 to the LMAa 25 in S202.

  Next, the network-based IP mobility protocol processing unit 18 of the LMAa 25 that has received the location registration from the MAGb 24 extracts the MNa-ID included in the location registration, and uses the MNa-ID as a key to indicate the current state of the MNa 21. Search is performed from data held in the storage unit 19 of the LMAa 25. The network-based IP mobility protocol processing unit 18 grasps that the MNa 21 belongs to the MAGa 22 in the data. The network-based IP mobility protocol processing unit 18 of the LMAa 25 recognizes that the MNa 21 has moved by receiving the location registration from the MAGb 24 although the MNa 21 currently belongs to the MAGa 22 in the data.

  Therefore, in S203, the network-based IP mobility protocol processing unit 18 of the LMAa 25 transmits a routing setup including at least the LMAa-ID identifier of the LMAa 25 and the global address of the MNa for creating the LMAa-MAGb tunnel to the MAGb 24. .

  In S204, the network-based IP mobility protocol processing unit 18 of the LMAa 25 instructs the MAGa 22 to transfer a buffer transfer / header compressed information including at least the identifier of the MNa 21, the identifier of the MNa-ID and the MAGb 24, the MAGb-ID or the IP address. Send. As shown in FIG. 7, this buffer transfer / header compressed information transfer instruction may be included in a message for location deregistration, that is, the LMAa25-MAGa22 tunnel deletion required so far, or transmitted separately. May be. After transmitting this header compression information to the MAGb 24, the network-based IP mobility protocol processing unit 13 of the MAGa 22 deletes the header compression information regarding the MNa 21 from the storage unit 14.

  FIG. 8 shows an example of header compression information. FIG. 8A shows an example of header compression information for MNa21, and FIG. 8B shows an example of header compression information for MNb23.

  Upon receiving the buffer transfer / header compressed information transfer instruction from the LMAa 25, the network-based IP mobility protocol processing unit 13 of the MAGa 22 reads out from the storage unit 14 in S205, and at least the MAGa-ID and MNa-ID, as shown in FIG. A tunnel generation request / header compression information message including such header compression information is transmitted to the MAGb 24.

  The network-based IP mobility protocol processing unit 13 of the MAGb 24 that has received the tunnel generation request / header compression information message from the MAGa 22 sets a tunnel route with the MAGa 22 and confirms the tunnel generation request / header compression information Ack in S206. Is transmitted to the MAGa 22 so that the packet addressed to the MNa 21 in the buffer (primary storage unit) 15 of the MAGa 22 can be transferred to the MAGb 24. The tunnel route is realized by encapsulating IPv6 in IPv6 with the IP address of MAGb24 as the outer destination address and the IP address of MAGa22 as the outer source address. Further, the network-based IP mobility protocol processing unit 13 of the MAGb 24 stores the received header compression information in the storage unit 14.

  The network-based IP mobility protocol processing unit 13 of the MAGb 24 that has received the routing setup sets up a tunnel path between the LMAa 25 and the MAGb 24 and transmits the routing setup Ack to the LMAa 25.

  Further, the network-based IP mobility protocol processing unit 13 of the MAGa 22 that has received the tunnel generation request / header compression information Ack, in S208, identifies the packet addressed to the address of the MNa 21 identified from the MNa-ID, the MAGb 24 identified from the MAGb-ID. Start forwarding to the IP address of

  Upon receiving the routing setup Ack from the MAGb 24, the network-based IP mobility protocol processing unit 18 of the LMAa 25 transmits a location registration Ack including at least prefix information of the MNa 21 to the MAGb 24 in S209.

  Upon receiving the location registration Ack from the LMAa 25, the network-based IP mobility protocol processing unit 13 of the MAGb 24 transmits the RA to the MNa 21 based on the prefix information in S210.

  The MNa 21 that has received the RA from the MAGb 24 transmits the NA to the link in the DAD procedure in S211.

  After receiving this NA from the MNa 21, the network-based IP mobility protocol processing unit 13 of the MAGb 24 transmits a MNb setup including the MAGb-ID, the address of the MNa 21, and the MNa-ID to the LMAa 25 in S 212. In S 213, the LMAa 25 The network-based IP mobility protocol processing unit 18 transmits a confirmation MN address setup Ack to the MAGb 24.

  After S214, the network-based IP mobility protocol processing unit 13 of the MAGb 24 outputs a packet including the transfer packet from the MAGa 22 to the compression / decompression processing unit 16, and the compression / decompression processing unit 16 refers to the compression information in the storage unit 14. Then, the header is compressed, and the network-based IP mobility protocol processing unit 13 starts delivery of the packet from the wireless communication unit 12 to the MNa 21.

  Further, when a header-compressed packet is received from the MNa 21, the network-based IP mobility protocol processing unit 13 of the MAGb 24 outputs the packet to the compression / decompression processing unit 16, and the compression / decompression processing unit 16 The header of the packet can be expanded and transferred to the LMAa 25.

9 and 10 are diagrams showing examples of packet formats. Note that various fields are omitted from the packets in FIGS. 9 and 10, and the actual packet does not conform to this format. FIG. 9A shows the field type of the packet before header compression.
As shown in FIG. 9A, the packet includes an outer source address (Outer Src IP), an outer destination address (Outer Dst IP), an inner source address (Inner Src IP), and an inner destination address (header portion). Inner Dst IP), UDP, RTP, and a payload which is a data body.

  When the present invention is used, the inner Dst IP address of the packet in the MN direction is “MNaIP” as shown in FIG. 9B, and the MN that the MAG wants to deliver can be identified.

  As a result, when a packet as shown in FIG. 9B arrives, the MAG compression / decompression processing unit 16 refers to the data as shown in FIG. ), The header can be compressed and the header can be compressed, and the MAG can grasp that it is delivered to the MNa 21, so that the packet can be correctly delivered to the MNa 21.

  When the packet as shown in FIG. 9D arrives, the MAG compression / decompression processing unit 16 refers to the compression information as shown in FIG. 8B for the MNb 23 stored in the storage unit 14, and the ROHC header And deliver it to MNb23.

  In the MAG, the packet from the MN can be grasped by the wireless communication means 12 from which MN the bearer information, for example, the MAC address or the like is received. As a result, when a packet as shown in FIG. 10A is received from the MNa 21, the compression information as shown in FIG. 8A for the MNa 21 in the storage unit 14 is referred to, and the IP / UDP / RTP header is changed to that shown in FIG. ) And the destination can be recognized as LMAa25, so that the packet can be transmitted to LMAa25.

  When the packet as shown in FIG. 10A arrives from the MNb 23, the MAG compression / decompression processing unit 16 refers to the compression information for the MNb 23 in the storage unit 14 as shown in FIG. Since the destination can be recognized as the LMAb 26 as shown in FIG. 10C, the packet can be transmitted to the LMAb 26.

  In this embodiment, the LMAa 25 instructs the MAGa 22 to perform buffer transfer and header compression information transfer, and puts the tunnel generation offer from the MAGa 22 to the MAGb 24 and the header compression information in the same message, thereby buffering tunneling and header compression information. The case where the notification is performed efficiently has been described. As a result, packets addressed to the MNa 21 accumulated in the buffer of the MAGa 22 are transferred via the MAGb 24, and the header compression information can be obtained by the MAGb 24. Therefore, the header is compressed without packet loss after the handover and the packet is sent to the MNa 21. It becomes possible to deliver.

  Note that the communication system, control device, router and communication method using the network-based IP mobility protocol of the present invention are not limited to the above-described illustrated examples, and may be variously within the scope of the present invention. Of course, changes can be made.

It is the figure shown about the schematic structure of the network in 1st Embodiment. It is the sequence diagram which showed the procedure of the process in 1st Embodiment. It is the block diagram which showed the structure of MAG in this invention. It is the block diagram which showed the structure of LMA in this invention. It is an example of the header compression information in 1st Embodiment. It is the figure shown about the schematic structure of the network in 2nd Embodiment. It is the sequence diagram which showed the procedure of the process in 2nd Embodiment. It is an example of the header compression information in 2nd Embodiment. It is an example of the format of a packet. It is an example of the format of a packet. It is the sequence diagram which showed the procedure of the process of the conventional fast handover method. It is the sequence diagram which showed the procedure of the process of the hand-over method in the conventional network base IP mobility protocol. It is the sequence diagram which showed the procedure of the process of the handover by the Proxy Mobile IP system of the conventional network base IP mobility protocol.

Explanation of symbols

1, 2, 23 MN
2, 3, 4, 22, 24 MAG
5, 25, 26 LMA
6, 9 CN
7 Internet 8 Router
10 AAA servers 11, 12, 17 Communication means 13, 18 Network-based IP mobility protocol processing unit 14, 19 Storage unit 15 Temporary storage unit 16 Compression / decompression processing unit

Claims (10)

Using a network-based IP mobility protocol, a mobile terminal performs communication by transmitting and receiving data from a router belonging to the same link using a uniquely assigned address. When the mobile terminal moves to another network, control is performed. A communication system for switching communication by controlling a device,
The router in the destination network of the mobile terminal is
Receiving a notification including the identifier of the mobile terminal from the mobile terminal, and transmitting a notification including the identifier of the mobile terminal and the identifier or IP address of the router to the control device;
The control device transmits a header compressed information transfer instruction notification to the source router of the mobile terminal so as to transfer header compressed information from the source router to the destination router. A communication system using the base IP mobility protocol.   The control device transmits a header compressed information transfer instruction notification to the source router of the mobile terminal and a buffer for transferring data addressed to the mobile terminal from the source router to the destination router The communication system using the network-based IP mobility protocol according to claim 1, wherein a transfer instruction notification is transmitted.   The communication system using the network-based IP mobility protocol according to claim 2, wherein the control device synthesizes and transmits the header compression information transfer instruction notification and the buffer transfer instruction notification. When a mobile terminal moves to another network in a system that uses a network-based IP mobility protocol and communicates by transmitting and receiving data from a router belonging to the same link by an address uniquely assigned to the mobile terminal. A control device that performs control for switching communication,
Communication means for receiving a notification including an identifier of the mobile terminal and an identifier or an IP address of the mobile terminal from the router in the network to which the mobile terminal is moved;
Storage means for holding communication information relating to the router and the mobile terminal performing relay;
Refer to the storage means for communication information of the mobile terminal from the identifier of the mobile terminal included in the notification from the router, update the information on the destination router and data transfer between the routers,
Control means for generating a header compressed information transfer instruction notification including an identifier of the mobile terminal and an identifier or IP address of the destination router for instructing the source router to transfer header compressed information to the destination router And
The control device, wherein the communication means transmits the header compressed information transfer instruction notification to the source router.   The control means instructs to transfer data addressed to the mobile terminal from the source router to the destination router, and a buffer transfer instruction including an identifier or IP address of the destination router and the destination router 5. The control apparatus according to claim 4, wherein a notification is generated, and the communication unit transmits the header compressed information transfer instruction notification and the buffer transfer instruction notification to the source router.   6. The control apparatus according to claim 5, wherein the communication unit synthesizes and transmits the header compressed information transfer instruction notification and the buffer transfer instruction notification to the source router. A router that transmits and receives data to and from a mobile terminal belonging to the same link that communicates with a uniquely assigned address under the control of a control device using a network-based IP mobility protocol
Storage means for storing header compression information when transmitting data to the mobile terminal;
From the control device, a header compressed information transfer instruction notification including an identifier of the mobile terminal for instructing transfer of the header compressed information to the destination router of the mobile terminal and an identifier or IP address of the destination router is received. Communication means;
A router comprising: control means for transferring the header compression information to the destination router by the transfer instruction notification.   The communication means includes an identifier of the mobile terminal for instructing transfer of data addressed to the mobile terminal from the control device to the destination router of the mobile terminal, and a buffer transfer instruction including an identifier or IP address of the destination router 8. The router according to claim 7, wherein the router receives the notification, and the control means transmits the header compression information and forwards the data addressed to the mobile terminal. Using the network-based IP mobility protocol, the mobile terminal is made to transmit and receive data from a router belonging to the same link using a uniquely assigned address. When the mobile terminal moves to another network, the control device A communication method for performing control for switching communication of the mobile terminal,
In the router in the network to which the mobile terminal is moving,
Receiving notification from the mobile terminal and detecting movement of the mobile terminal to the same link;
Notifying the control device of the movement of the mobile terminal,
In the control device,
Transmitting a header compression information transfer instruction notification for instructing transfer of header compression information to the destination router to the movement source router.   10. The control device according to claim 9, further comprising a step of transmitting a buffer transfer instruction notification instructing transfer of data addressed to the mobile terminal to the destination router to the source router. Communication method.

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