JP2006246125A - Communication control method for packet communication system, and packet communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a seamless hand-over reduced in packet loss while reducing the traffic quantity of position registration. <P>SOLUTION: A space control server 16 receives a position registration request to be transmitted when an MN 22 enters into a network in any one of areas charged by an AR 12 and determines a duplication/transfer range node group including the AR 12 and a boundary node applied to an area in charge which is a boundary of a duplication/transfer area which is an aggregate of areas charged by respective ARs in response to the position registration request. Then the space control server 16 instructs nodes having a function for duplicating and transferring packets to the MN 22 to duplicate packets and transfer these duplicated packets to respective ARs constituting the duplication/transfer range node group and transmits information indicating the duplication/transfer range node group and the boundary node to the MN 22. At the time of judging that a node included in another area in charge is the boundary node when the MN 22 moves to another area in charge belonging to the duplication/transfer area, the position registration request is transmitted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a packet communication system, and more particularly to a communication control method in a mobile communication system.

  In realizing IP mobility by mobile IP, there is a need for efficient location registration control and fast handover. For example, in location registration, a reduction in traffic volume and a reduction in processing load during location registration are required. In addition, it is desirable that seamless handover is possible even when the mobile node (MN) is moving at high speed.

N-casting is known as a representative technique for solving the above-described problems. In n-casting, a packet is transmitted to a care-of address (CoA: Care of Address) that can be used by the MN in a plurality of access routers (ARs) that are candidates for the movement destination of the MN, and within the range in which the packet is transmitted. If the MN receives a packet transmitted to each CoA, the packet is seamlessly received with less packet loss within a range determined by a plurality of ARs of predetermined destination candidates. (For example, Patent Document 1, Patent Document 2, and Patent Document 3)
JP 2004-228754 A JP 2002-84562 A JP 2003-259455 A Zhang Ryo, Ono Natsuko, Kimura Tohru, Hiroshige Kazuhito and Hayashi Hideki, "Implementation and Evaluation of Spatial Control Platform in IP Mobility", (The Institute of Electronics, Information and Communication Engineers, Information Network Study Group, December 17, 2004)

  However, when n-casting is employed, a high-speed handover with little packet loss can be realized, but there is a problem that the amount of traffic related to location registration cannot be reduced.

  For example, as described in Non-Patent Document 1, when a MN exists under a certain AR (AR # 0), an AR group (AR # 1, AR # 2) that is a destination candidate is specified. Thus, a technique has been proposed in which a packet is duplicated and transferred to an area including the AR where the MN exists and the AR group of destination candidates. Thereby, seamless handover can be realized in a certain area. However, the traffic volume related to location registration could not be reduced.

  In addition, as described in Patent Document 3, when the MN moves within an area where copy transfer including a destination destination AR group is performed, location registration is not performed and copy transfer is performed. A technique for registering a location when going outside has been proposed. As a result, seamless handover can be realized in a certain area, and the amount of traffic related to location registration can be reduced. However, this technique has a problem in that packet loss may occur at the change of the area including the AR group.

  An object of the present invention is to provide a system and method capable of realizing seamless handover with less packet loss while reducing the amount of traffic related to location registration.

  In the present invention, the mobile communication system performs a network layer (switching plane) that performs simple packet-by-packet processing such as routing / switching and tunneling, and controls (for example, spatial control such as location management and n-casting) and signaling. Separated into the mobility control layer (mobility control plane) to handle. The mobility control plane receives a location registration request from a terminal device such as a mobile node (MN), registers and manages the correspondence between the home address and the care-of address, and sends packets addressed to the home address to the corresponding switching plane node. To tunnel to the care-of address. Further, when performing n-casting, a replication transfer area and a node to perform replication transfer are determined, and n-casting processing is instructed to the node of the corresponding switching plane. On the other hand, in response to an instruction from the mobility control plane, the switching plane performs n-casting processing in addition to tunneling (encapsulating) packets addressed to the home address to the care-of address.

  In the present invention, a duplication / transfer area composed of node areas such as a plurality of access routers (AR) is set. Here, the assigned area refers to a range (cover area) in which one AR provides communication. In the replication transfer area, the node in the area in charge that constitutes the boundary of the replication transfer area is determined as the boundary node. Information indicating the replication transfer area and the boundary node is notified to the terminal device. In the replication transfer area, the terminal device does not transmit a location registration request under the jurisdiction of a node other than the boundary node, and transmits a location registration request only when the terminal device is under the jurisdiction of the boundary node. For example, a control device that can communicate with a node via a network, such as a spatial control server, determines the replication transfer area and the boundary node.

  As described above, when a node other than the border node is under the jurisdiction, by not transmitting a location registration request, it is possible to reduce the load of location registration processing and reduce the traffic volume. In addition, when a terminal device moves between the duplicate transfer areas and performs handover, a new duplicate transfer area including the boundary node is set at the boundary node belonging to the duplicate transfer area before leaving the duplicate transfer area. Therefore, packet loss can be avoided.

More particularly, the object of the present invention is to
In a packet communication system comprising a plurality of nodes connected to each other via a network, a terminal device that transmits and receives packets via the node, and a space control server that can communicate with the terminal device, the space control server Receiving a location registration request transmitted from the terminal device when the terminal device enters the network in the area in charge of any of the plurality of nodes, and the received location registration In response to the request, the spatial control server determines a group of nodes including the first node as a replication transfer range node group, and is responsible for the replication transfer range node group among the nodes constituting the macro cell group. A step for determining a node in the assigned area that forms the boundary of the replication transfer area, which is a collection of areas, as the boundary node. And, in the spatial control server, for a node having a function of replicating and forwarding a packet addressed to the terminal device, a packet destined for the terminal device is duplicated to a node constituting the duplicate transfer range node group, and A step of instructing transfer to each of the nodes constituting the replication transfer range node group, and a step of transmitting information indicating the replication transfer range node group and the boundary node to the terminal device in the spatial control server; In the space control server, when the terminal device moves to another assigned area belonging to the duplicate transfer area, the assigned information is referred to by referring to the information indicating the duplicate transfer range node group and the boundary node transmitted to the terminal. Receiving a location registration request transmitted when a node in the area is determined to be a border node; It is realized by a communication control method characterized by comprising a.

  In the present invention, the spatial control server belongs to the mobility control plane. An access router can be used as a node. According to the present invention, when the terminal device moves in the replication transfer area, the terminal device does not transmit a location registration request unless the node in the destination assigned area is a boundary node. Therefore, it is possible to reduce the amount of traffic related to location registration. Further, when it is located at the boundary node, it transmits a location registration request, and the space control server determines a new replication transfer area according to this, and notifies the terminal device of the information. As a result, it is possible to avoid the occurrence of packet loss when updating the replication transfer area.

  In another aspect, a communication control method includes: a plurality of nodes connected to each other via a network; and a terminal device that transmits and receives a packet via the node. In any one of the first nodes, the terminal device receives or transfers a location registration request to be transmitted when entering the network in the assigned area, and the terminal device is assigned to the assigned area of the first node. Upon entering, the first node determines a group of nodes including the first node as a replication transfer range node group, and among the nodes constituting the replication transfer range node group, the replication The node in the assigned area that forms the boundary of the replication transfer area, which is a collection of assigned areas of the transfer range node group, is determined as the boundary node A step of transmitting, to the terminal device, information indicating the copy transfer range node group and the boundary node in the first node, and the terminal device moves to another assigned area belonging to the copy transfer area. The location registration request transmitted when the node in the area in charge is determined to be a boundary node with reference to the information indicating the replication transfer range node group and the boundary node transmitted to the terminal. Receiving the boundary node.

As yet another aspect, a communication control method includes a plurality of nodes connected to each other via a network, a terminal device that transmits and receives packets via the node, and a function that manages the position of the terminal device. In the packet communication system provided with the home agent, in the home agent, the location registration request transmitted when the terminal device enters the network in the assigned area in the first node of the plurality of nodes. Receiving the step,
In response to the location registration request, the home agent determines a group of nodes including the first node as a replication transfer range node group, and among the nodes constituting the replication transfer range node group, the replication Determining a node related to a responsible area that forms a boundary of a duplicate forwarding area, which is a collection of responsible areas of a forwarding range node group, as a boundary node;
In the home agent, transmitting information indicating the replication transfer range node group and the boundary node to the terminal device;
In the home agent, when the terminal device moves to another assigned area belonging to the duplicate transfer area, the responsible agent refers to the information indicating the duplicate transfer range node group and the boundary node transmitted to the terminal device. Receiving a location registration request transmitted when it is determined that the node in the area is a boundary node.

In a preferred embodiment, the step of determining the replication transfer range node group and the boundary node includes a plurality of second areas such that the first node has an assigned area spatially within a predetermined range with the assigned area of the first node. Selecting a node of
Determining the first node and the second node as the replication transfer range node group, and a second node having a responsible area located spatially outermost among the responsible areas, Determining a boundary node.

  In a more preferred embodiment, the step of determining the replication transfer range node group and the boundary node includes the step of determining the replication transfer range node group in consideration of a moving direction and a moving speed of the terminal device.

  Another object of the present invention is to provide a packet comprising a plurality of nodes interconnected via a network, a terminal device that transmits and receives packets via the node, and a spatial control server that can communicate with the terminal device. In the communication system, the space control server transmits a location registration transmitted from the terminal device when the terminal device enters the network in an area in charge of any one of the plurality of nodes. In response to the request, replication transfer range node group determining means for determining a group of nodes including the first node as a replication transfer range node group, and the replication transfer among the nodes constituting the replication transfer range node group Boundary node determining means for determining, as a boundary node, a node related to the assigned area that forms the boundary of the replication transfer area that is an aggregate of the assigned areas of the range node group; For a node having a function of duplicating and forwarding a packet addressed to the terminal device, a packet destined for the terminal device is duplicated to a node constituting the duplication and forwarding range node group to constitute the duplicate forwarding range node group Transfer instruction means for instructing transfer to each of the nodes, information transmission means for transmitting information indicating the copy transfer range node group and boundary node to the terminal device, and the terminal device belongs to the copy transfer area When moving to another assigned area, reference is made to the information transmitted by the information transmitting means, and a location registration request is received when it is determined that the node in the assigned area is a boundary node. And a position registration receiving means.

Another object of the present invention is a packet communication system comprising a plurality of nodes connected to each other via a network, and a terminal device that transmits and receives packets via the nodes,
When a first node of any of the plurality of nodes has entered the area in charge of the first node, a group of nodes including the first node are duplicated transfer range nodes. A replication transfer range node group determining means for determining a group, and among the nodes constituting the replication transfer range node group, an assigned area that forms a boundary of a replication transfer area that is a collection of the assigned areas of the replication transfer range node group Boundary node determination means for determining such a node as a boundary node;
Information transmitting means for transmitting information indicating the replication transfer range node group and the boundary node to the terminal device;
When the boundary node moves to another assigned area belonging to the replication transfer area, the node related to the assigned area is a boundary node with reference to the information transmitted by the information transmitting means It is achieved by a packet communication system comprising location registration reception transfer means for receiving or transferring a location registration request transmitted when it is determined.

In a preferred embodiment, the replication transfer range node group determining means selects a plurality of second nodes having a service area that is spatially within a predetermined range with the service area of the first node. , Configured to determine the first node and the second node as the replication transfer range node group,
The boundary node determining means is configured to determine, as a boundary node, a second node having a responsible area located spatially outermost among the assigned areas.

  In a further preferred embodiment, the duplicate transfer range node group determining means is configured to determine the duplicate transfer range node group in consideration of the moving direction and moving speed of the terminal device.

  According to the present invention, it is possible to provide a system and a method capable of realizing a seamless handover with little packet loss while reducing the amount of traffic related to location registration.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a block diagram showing an outline of a mobile communication system according to the present embodiment. As shown in FIG. 1, in a mobile communication system, a plurality of access routers (AR) 12-1, 12-2,... Each having a certain assigned area are arranged. The AR transfers a packet from the terminal device (MN) 22 belonging to its own area, or transfers a packet addressed to the care-of address (CoA) of its own area. In FIG. 1, the assigned areas of AR12-1, 12-2,..., 12-7 are denoted by reference numerals 100-1, 100-2,. In some cases, AR12-1, AR12-2,... Are also referred to as AR1, AR2,. In some cases, the duplicate transfer nodes 18-1 and 18-2 are also referred to as R1 and R2.

  In the present embodiment, in addition to the home agent (HA) 14, the space control server 16, replication transfer nodes 18-1, 18-2,... Are connected to the network 20. In this embodiment, the mobile communication system performs a simple packet-by-packet processing such as routing / switching and tunneling (switching plane), control (for example, spatial control such as location management and n-casting) and signaling. It is separated from the mobility control layer (mobility control plane) that handles In FIG. 1, the spatial control server 16 belongs to the mobility control plane, manages and controls signaling, and gives an operation instruction to devices constituting the switching plane. In FIG. 1, the AR 12, HA 14, and replication forwarding node 18 belong to the switching plane, and execute processing such as forwarding / encapsulation of packets according to instructions from the space control server 16. The HA 14 has a function of transferring a packet addressed to the home address to the care-of address among the functions of the mobile IP home agent. In FIG. 1, only the space control server 16 is illustrated as a device belonging to the mobility control plane, and the space control server 16 manages the location registration of the MN in addition to the management control of signaling as described later. . That is, the space control server 16 also has a location management function possessed by the mobile IP home agent. However, the location management function of the mobile IP home agent is provided as a location management server and separately from the space control server, manages the location of the MN in the mobility control plane, and gives necessary instructions to the HA 14. You may comprise as follows.

  In the present embodiment, as will be described later, the space control server 16 determines a replication transfer area to which a packet replication is to be transferred for each MN 22. The duplicate forwarding node 18 has a function of duplicating a packet to be forwarded to the duplicate forwarding area and forwarding the duplicated packet to each AR in the area in charge constituting the duplicate forwarding area. Hereinafter, a group of ARs each having an assigned area constituting a replication transfer area is also referred to as a replication transfer range node group. In other words, each aggregated area of ARs constituting the replication transfer range node group can be considered as a replication transfer area.

  In FIG. 1, a collection of AR 12-1 to 12-4 replication transfer range node groups in charge (see reference numerals 1001-1 to 100-4) forms a first replication transfer area 110-1. An aggregate of the areas in charge of the replication transfer range node groups AR12-3 to 12-7 (see reference numerals 100-3 to 100-7) forms a second replication transfer area 110-2. However, the replication transfer area is not predetermined or fixed, but is determined by the space control server 16 based on the moving direction and moving speed of the MN.

  Furthermore, in the present embodiment, of the ARs constituting the replication transfer range node group, the AR whose assigned area is located on the outermost side of the replication transfer area is referred to as a boundary node. In FIG. 1, for the first replication transfer area 110-1, AR12-1 and AR12-4 are boundary nodes. For the second replication transfer area 110-2, AR12-3 and AR12-7 are boundary nodes. In FIG. 1, since the ARs are arranged one-dimensionally, the ARs physically located at both ends are the boundary nodes. However, in reality, the replication transfer area is two-dimensional or three-dimensional. An AR having a sufficient area surrounding the replication transfer area can be a boundary node.

FIG. 2 is a diagram showing an outline of location registration control according to the present embodiment. For example, when entering the access network for the first time, such as when the MN 22 is turned on, the MN transmits a location registration or a replication transfer area setting request to be described later. Also in the example of FIG. 2, similarly to FIG. 1, AR1 to AR4 constitute a replication transfer range node group, and a first replication transfer area is formed by an aggregate of the assigned areas, and AR1 and AR4 are It becomes a boundary node for the first replication transfer area.

  In the example of FIG. 2, for example, when the power of the MN 22 is turned on in the assigned area 100-1 of the AR 12-1, the MN 22 transmits a location registration request via the AR 12-1. As will be described later, the MN 22 is notified from the space control server 16 of information indicating the AR having each of the assigned areas constituting the replication transfer area, and the MN configures a replication transfer range node group related to the replication transfer area. AR information can be grasped.

  For example, when the MN 22 moves and is located in the assigned area 100-2 of the AR 12-2 that is not a boundary node, the location registration is not executed. Similarly, when the MN 22 is located in the assigned area 100-3 of the AR 12-3 that is not a boundary node, the location registration is not executed. In a certain duplication transfer area, the duplicated packet is transferred (n-casting) via each AR of the assigned area constituting the duplication transfer area.

  On the other hand, when the MN 22 further moves and is located in the assigned area 100-4 of the AR 12-4 that is the boundary node, a location registration request is transmitted. In this location registration request, the space control server 16 notifies the MN 22 of information on ARs that constitute a replication transfer range node group related to a new replication transfer area. A more detailed processing sequence will be described later.

  FIG. 3A is a block diagram showing the configuration of the MN 22 according to the present embodiment. In FIG. 3 (a), description is omitted about the component which implement | achieves the function similar to the past of MN22, for example, packet transmission / reception etc., and only the component regarding the location registration request | requirement concerning this invention is shown. As shown in FIG. 3 (a), the MN 22 transmits a location registration request when entering the access network for the first time such as when the power is turned on, or when it is located in the area in charge of the boundary node. A location registration requesting unit 30 that receives information, an AR table generating unit 32 that generates an AR table 34 that includes information about an AR that constitutes a replication transfer range node group related to the replication transfer area to which it belongs, and all of the replication transfer areas in the replication transfer area And a CoA generation unit 36 that generates a CoA and stores it in the CoA table 38. The configuration of the AR table 34 will be described in detail later.

  4 and 5 are flowcharts showing the location registration process of the MN in the mobile communication system according to the present embodiment. For example, it is assumed that the MN 22 enters the access network for the first time such as turning on the power in the area in charge of AR1 (corresponding to AR12-1 in FIG. 1). The MN 22 transmits a location registration request to the space control server 16 via AR1 (step 401). As described above, in the present embodiment, the space control server 16 also has a location registration function, and the space control server 16 registers the location of the MN 22 in accordance with the location registration request (step 402). Also, the space control server 16 stores the correspondence between the home address and the CoA based on the location registration request, and gives an instruction for realizing packet tunneling to the HA 14 (step 403). Based on the position of the MN 22, the space control server 16 determines a replication transfer range node group related to the replication transfer area, which is a packet replication transfer destination (step 404). In this example, in step 404, the space control server 16 determines AR1 to AR4 as a replication transfer range node group related to the replication transfer area, and determines AR1 and AR4 as boundary nodes. In step 404, a duplicate transfer node (see reference numeral 18-1 in FIG. 1), which is a node having a duplicate transfer function, is also determined.

  The space control server 16 instructs the determined replication transfer node 18-1 to replicate and transfer the packet, that is, n-casting (step 405). Here, the space control server 16 notifies the determined transfer forwarding node 18-1 of the CoA registered in the space control server 16 and the CoA in each AR assigned area in the MN copy transfer area. Further, the space control server 16 sends a location registration response to the MN 22 via the AR 1, the network prefix information of the AR of the replication transfer range node group regarding the replication transfer area, and the boundary node in the replication transfer range node group regarding the replication transfer area. The identifier of the AR to be transmitted is transmitted (step 406).

  When the MN 22 receives the location registration response, the network prefix information of the replication transfer area, and the identifier of the boundary node from the space control server 16, it generates all the CoAs in each responsible area constituting the replication transfer area based on the network prefix information. Then, it is stored in its own CoA table 38 (step 407). Further, the MN 22 generates the AR table 34 based on the network prefix information (step 408). FIG. 3B is a diagram illustrating an example of the AR table generated in step 408. As shown in FIG. 3B, the AR table 34 stores the network prefixes of ARs (AR1 to AR4) that constitute the replication transfer range node group related to the replication transfer area. In addition, AR (AR1 and AR4) corresponding to the boundary nodes stores “1” as a boundary node flag.

  As described above, the space transfer server 16 gives a copy transfer instruction to the copy transfer node R1. Therefore, a packet destined for the home address of the MN is intercepted by the HA 14 and tunneled to the CoA. Here, since the duplicate transfer node R1 is arranged in the path from the HA 14 to the CoA, the duplicate transfer node duplicates and transfers the packet to all the notified CoAs (see step 409).

  Since the MN 22 is provided with the CoA table 38, a packet addressed to any CoA can be received when the MN 22 is located in any responsible area constituting the copy transfer area. Thereby, it is possible to realize reception without packet loss in the replication transfer area.

As shown in FIG. 5, a case is considered where the MN 22 moves to the AR2 or AR3 area (see step 501). The movement of the area in charge is performed by RA (Router) output from the AR.
It can be detected by receiving (Advertisement) (step 502). With reference to the AR table 34, the MN 22 does not output a location registration request when the destination area in charge is in the replication transfer area and the AR in the destination area is not a boundary node ( Reference numeral 503).

  On the other hand, let us consider a case where the MN 22 moves to the area in charge of AR4 (see step 504). When the MN 22 receives the RA from the AR 4 (step 505), the MN 22 refers to the AR table 34 and recognizes that the destination AR is a boundary node. Therefore, the MN 22 transmits a location registration request to the space control server 16 via the AR 4 (step 506).

  The space control server 16 registers the position of the MN 22 in accordance with the position registration request (step 507). Next, the space control server stores the correspondence between the home address and the CoA based on the location registration request, and gives an instruction for realizing packet tunneling to the HA 14 (step 508). Based on the position of the MN 22, the space control server 16 updates the replication transfer area that is the replication transfer destination of the packet. That is, the replication transfer range node group relating to the replication transfer area is set again (step 509). In the example of FIG. 1, AR <b> 3 to AR <b> 7 are set as ARs that constitute the replication transfer range node group with the movement of the MN 22. In this example, the boundary nodes are determined as AR3 and AR7. Further, a duplicate transfer node (see reference numeral 18-2 in FIG. 1), which is a node having a duplicate transfer function, is also determined.

  The “n-casting” setting (step 510) for the duplicate forwarding node 18-2 (R2 in FIG. 2) corresponds to step 405 in FIG. Steps 511 to 513 in FIG. 5 correspond to steps 406 to 408 in FIG. 4. In step 511, information indicating the network prefixes of AR3 to AR7 is transmitted to the MN 22 as network prefix information of the replication transfer area, and information indicating AR3 and AR7 is transmitted to the MN 22 as identifiers of boundary nodes. Sent. FIG. 3C is a diagram illustrating an example of the AR table generated in step 513. As shown in FIG. 3C, the AR table 34 stores the network prefixes of the ARs (AR3 to AR7) that constitute the replication transfer range node group related to the replication transfer area. In addition, AR (AR3 and AR7) corresponding to the boundary nodes stores “1” as a boundary node flag.

  Thereby, in the replication transfer range node groups AR3 to AR7 regarding the new replication transfer area, the MN 22 can receive a packet addressed to the new CoA. In addition, a location registration request is not transmitted when moving between ARs other than when moving to the boundary node AR3 or AR7.

  As described above, according to the present embodiment, the MN 22 grasps the AR information and the boundary node information that constitute the replication transfer range node group related to the replication transfer area, and performs the movement within the replication transfer area. If the movement destination is not the area in charge of the boundary node, the location registration is not transmitted. As a result, it is possible to realize a reduction in the amount of traffic related to location registration. On the other hand, even if the movement is within the replication transfer area, if the movement destination is the area in charge of the boundary node, a location registration request is transmitted. As a result, the MN 22 can acquire information on a new replication transfer area (that is, information on ARs that constitute a new replication transfer range node group). As a result, the MN 22 belongs to a new replication transfer area, and it is possible to avoid packet loss at the transition of the replication transfer area (or switching of the replication transfer area).

  Next, a second embodiment of the present invention will be described. In the second embodiment, as shown in FIG. 6, in the mobile communication system according to the second embodiment, the space control server is not provided and the replication transfer area held by the space control server is related. All ARs hold the function of determining the replication transfer range node group and the boundary node. Also in the second embodiment, a collection of areas in charge of replication transfer range node groups (for example, AR1 to AR4, AR4 to AR7) constitutes a replication transfer area (see reference numerals 110-1 and 110-2). In the macro cell group, a boundary node is set. In the example of FIG. 6, AR1 and AR4 are boundary nodes with respect to the first duplication transfer area 110-1. In addition, for the second replication transfer area 110-2, AR4 and AR7 are boundary nodes.

  In the second embodiment, since the space control server is not provided, the determination of the replication transfer area (that is, the determination of the replication transfer range node group) is realized by each AR. Hereinafter, the location registration process in the mobile communication system according to the second embodiment will be described with reference to FIG. 7 and FIG. For example, it is assumed that the MN 22 enters the access network for the first time such as turning on the power in the area in charge of the AR 12-3 (corresponding to AR 3 in FIG. 6). The MN 22 transmits a location registration request to the HA 14 via the AR 3 (step 701). The HA 14 executes location registration processing in response to the location registration request (step 702), and transmits a location registration response to the MN 22 after the processing (step 704).

  AR3 determines a replication transfer range node group and a boundary node related to the replication transfer area, similarly to the spatial control server according to the first embodiment (step 703). The processing in step 703 is almost the same as the processing in step 404 in FIG. In the second embodiment, the AR also has a function of a node (see reference numerals 18-1 and 18-2 in the first embodiment) having a replication transfer function. After the processing of Step 703, AR3 transmits the copy transfer area information, that is, the network prefix information of the copy transfer area and the identifier of the boundary node to MN 22 (Step 705). The notification of information from the AR to the MN in Step 705 may use RA. Further, when the AR transmits to the MN, the packet may be notified together. The timing for notifying the copy transfer area information may be the timing for responding to Router Solicitation (router request) from the MN. Furthermore, it may be the timing when the packet is transmitted from the MN for the first time, or the timing when the AR transmits the packet for the first time to a new CoA. The processing of steps 706 and 707 in the MN 22 is the same as the processing of steps 407 and 408 in FIG. Thereafter, AR3 copies and forwards the packet to all the CoAs in the replication transfer area (step 708).

  Consider a case where the MN 22 moves to the AR2 or AR3 area (step 801). FIG. 8 shows a case where the MN 22 moves to the AR2 area. Similar to the first embodiment, the movement of the assigned area can be detected by receiving the RA output from the AR (step 802). With reference to the AR table 34, the MN 22 does not output a location registration request when the destination area in charge is in the replication transfer area and the AR in the destination area is not a boundary node ( Reference numeral 803).

  On the other hand, consider a case where the MN 22 moves to a boundary node (AR1 or AR4 in the example of FIG. 8). For example, as shown in FIG. 8, when the MN 22 receives the RA from the AR 4 (step 805), the MN 22 refers to the AR table 34 and recognizes that the destination AR is a boundary node. Therefore, the MN 22 transmits a location registration request to the HA 14 via the AR 4.

  The HA 14 registers the location of the MN 22 in accordance with the location registration request (step 807), and returns a location registration response to the MN 22 (step 809).

  AR4 determines a new replication transfer area (step 808). That is, a new replication transfer range node group is determined. The network prefix information of the new replication transfer area and the identifier of the boundary node are transmitted to the MN 22 (Step 810), and all of the CoAs are generated and stored (Step 811) and the AR table is updated (Step 812). Is done.

  In the second embodiment, the AR has a function of determining a replication transfer range node group and a boundary node related to the replication transfer area held by the spatial control server in the first embodiment, and a function of the replication transfer node. However, it is also possible to realize these functions by a home agent in mobile IP and a mobility anchor point (MAP) in hierarchical mobile IP.

  According to the second embodiment, it is possible to reduce the amount of traffic related to location registration without providing a space control server, and to avoid packet loss even at the change of the replication transfer area.

  Next, determination of the replication transfer area according to the present invention will be described using an example. In the first embodiment, the space control server 16 determines a replication transfer area according to the position of the MN 22 or the like. In the first determination method, the space control server 16 sets the replication transfer area so that the assigned area to which the MN 22 belongs is substantially spatially centered in the replication transfer area. As shown in FIG. 9 (a), when the MN 22 is located in the AR4 charge area 900-4, the copy transfer area 910-1 is set so that two charge areas are located around the MN22. The ARs that are determined and have areas in charge at both ends thereof (that is, AR2 and AR6) are determined as boundary nodes. In FIG. 9A, in order to facilitate understanding, the AR assigned area is one-dimensionally represented. Of course, the AR assigned area is two-dimensionally or three-dimensionally arranged.

  When the MN 22 is located at the boundary node AR6, the space control server 16 determines a new replication transfer area 910-2 so that the AR6 is located substantially in the center, and is responsible for both ends. ARs having areas (that is, AR4 and AR8) are determined as boundary nodes. Also in the second embodiment, the method for determining the replication transfer area can be applied.

  Further, in addition to the above-described spatial positional relationship of the AR, the replication transfer area may be determined so that the assigned area is spatially increased in the moving direction in consideration of the moving direction and moving speed of the MN. . For example, as shown in FIG. 9B, if the MN moves in the direction of the arrow 920, the duplication transfer area is determined so that the number of assigned areas increases in that direction (see reference numeral 921). ). In this embodiment, the boundary node is an AR that is spatially located on the outermost side. However, for example, when the terminal device is moving at a high speed, switching of the replication transfer area is not in time, and packet loss occurs. Since there is a possibility, the boundary node may select a node that enables switching so that packet loss due to movement between areas does not occur.

In the above-described example, the duplication / transfer area is determined based on the positional relationship between the spatially assigned areas. However, the present invention is not limited to this. When there is a dependency relationship between the spatial arrangement of ARs and the network arrangement between ARs (when an AR that is spatially close is located in the number of hops close to the network), it is based on the network-like positional relationship between ARs. Thus, the replication transfer area may be determined. Here, the space control server 16 (the first embodiment) or each AR (the second embodiment) holds a table indicating how many hops the ARs are located apart from each other. When the server 16 or each AR determines a group of ARs within a certain hop count range as a replication transfer range node group with reference to this table, and the area in charge of the group of ARs is a replication transfer area. good. In this case, for example, a group of ARs with the largest number of hops may be determined as boundary nodes.
In general, the MN issues a location registration request when moving between ARs, and may also issue a location registration request when the lifetime of location registration expires. The present invention realizes a reduction in the amount of traffic related to location registration during movement between the former ARs. In the above-described embodiment, the MN does not transmit a location registration request in a non-boundary node. However, if the lifetime of the location registration request has expired, the location registration request may be transmitted even in a non-boundary node. The location registration request when the lifetime expires must be transmitted. Even in this case, the number of location registration request transmissions accompanying the movement of the MN can be reduced by the present invention.

  The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

FIG. 1 is a block diagram showing an outline of a mobile communication system according to an embodiment of the present invention. FIG. 2 is a diagram showing an outline of location registration control according to the present embodiment. 3A is a block diagram showing the configuration of the MN according to this embodiment, and FIGS. 3B and 3C are diagrams showing examples of the data configuration of the AR table stored in the MN. is there. FIG. 4 is a flowchart showing the location registration process of the MN in the mobile communication system according to the present embodiment. FIG. 5 is a flowchart showing the location registration process of the MN in the mobile communication system according to the present embodiment. FIG. 6 is a block diagram showing an outline of the mobile communication system according to the second embodiment of the present invention. FIG. 7 is a flowchart showing the location registration process of the MN in the mobile communication system according to the second embodiment. FIG. 8 is a flowchart showing the location registration process of the MN in the mobile communication system according to the second embodiment. FIG. 9 is a diagram for explaining an example of a macro cell group determination method related to the duplicate transfer area in the present invention.

Explanation of symbols

12 AR
14 HA
16 Spatial control server 18 Replica forwarding node 20 Network 22 MN
100 Area in charge 110 Replication transfer area

Claims (9)

In a packet communication system comprising a plurality of nodes connected to each other via a network, a terminal device that transmits and receives packets via the node, and a space control server that can communicate with the terminal device,
In the spatial control server, the terminal device receives a location registration request transmitted from the terminal device when entering the network in the area in charge of any first node of the plurality of nodes;
In response to the received location registration request, the spatial control server determines a group of nodes including the first node as a replication transfer range node group, and among the nodes constituting the replication transfer range node group, Determining a node related to the assigned area that forms the boundary of the duplicated transfer area, which is a collection of assigned areas of the duplicated transfer range node group, as a boundary node;
In the spatial control server, for a node having a function of replicating and forwarding a packet addressed to the terminal device, the packet destined to the terminal device is duplicated to a node constituting the replica transfer range node group, and the duplicate transfer is performed. Instructing transfer to each of the nodes constituting the range node group;
In the spatial control server, transmitting to the terminal device information indicating the replication transfer range node group and the boundary node;
In the space control server, when the terminal device moves to another assigned area belonging to the duplicate transfer area, the assigned area is referred to by referring to the information indicating the duplicate transfer range node group and the boundary node transmitted to the terminal. And a step of receiving a location registration request transmitted when it is determined that the node is a boundary node. In a packet communication system comprising a plurality of nodes connected to each other via a network, and a terminal device that transmits and receives packets via the nodes,
In the first node of any of the plurality of nodes, receiving or transferring a location registration request to be transmitted when the terminal device enters the network in the assigned area;
When the terminal device enters the area in charge of the first node, the first node determines a group of nodes including the first node as a duplication transfer range node group, and the duplication Determining, as a boundary node, a node related to a responsible area that forms a boundary of a duplicate transfer area, which is an aggregate of the responsible areas of the duplicate transfer scope node group, among nodes constituting the forwarding scope node group;
Transmitting information indicating the replication transfer range node group and the boundary node to the terminal device in the first node;
When the terminal device moves to another assigned area belonging to the replication transfer area, referring to the information indicating the replication transfer range node group and the boundary node transmitted to the terminal, the node associated with the assigned area is A communication control method, comprising: a step of receiving a location registration request transmitted when it is determined that the node is a boundary node. In a packet communication system comprising a plurality of nodes connected to each other via a network, a terminal device that transmits and receives packets via the node, and a home agent that has a function of managing the position of the terminal device,
In the home agent, in the first node of any of the plurality of nodes, receiving a location registration request transmitted when the terminal device enters the network in the assigned area;
In response to the location registration request, the home agent determines a group of nodes including the first node as a replication transfer range node group, and among the nodes constituting the replication transfer range node group, the replication Determining a node related to a responsible area that forms a boundary of a duplicate forwarding area, which is a collection of responsible areas of a forwarding range node group, as a boundary node;
In the home agent, transmitting information indicating the replication transfer range node group and the boundary node to the terminal device;
In the home agent, when the terminal device moves to another assigned area belonging to the duplicate transfer area, the responsible agent refers to the information indicating the duplicate transfer range node group and the boundary node transmitted to the terminal device. And a step of receiving a location registration request transmitted when it is determined that the node in the area is a boundary node. Determining the replication forwarding range node group and the boundary node;
Selecting a plurality of second nodes having a responsible area spatially within a predetermined range with the responsible area of the first node;
Determining the first node and the second node as the replication transfer range node group;
4. The method according to claim 1, further comprising: determining, as a boundary node, a second node having a responsible area located spatially outermost among the assigned areas. 5. . Determining the replication forwarding range node group and the boundary node;
5. The method according to claim 4, further comprising: determining the replication transfer range node group in consideration of a moving direction and a moving speed of the terminal device. A packet communication system comprising a plurality of nodes connected to each other via a network, a terminal device that transmits and receives packets via the node, and a spatial control server that can communicate with the terminal device,
The space control server responds to a location registration request transmitted from the terminal device when the terminal device enters the network in the area in charge of any one of the plurality of nodes. Replication transfer range node group determining means for determining a group of nodes including the first node as a replication transfer range node group;
Boundary node determination means for determining, as a boundary node, a node related to a responsible area that forms a boundary of a duplicated transfer area, which is an aggregate of assigned areas of the duplicated forwarding range node group, among the nodes constituting the duplicated forwarding range node group; ,
For a node having a function of duplicating and forwarding a packet addressed to the terminal device, a packet destined for the terminal device is duplicated to a node constituting the duplication and forwarding range node group to constitute the duplicate forwarding range node group Transfer instruction means for instructing transfer to each of the nodes;
Information transmitting means for transmitting information indicating the replication transfer range node group and the boundary node to the terminal device;
When the terminal device moves to another assigned area belonging to the replication transfer area and refers to the information transmitted by the information transmitting means, and determines that the node in the assigned area is a boundary node And a location registration receiving means for receiving a location registration request to be transmitted. A packet communication system comprising a plurality of nodes connected to each other via a network, and a terminal device that transmits and receives packets via the nodes,
A first node of any of the plurality of nodes is
A replication transfer range node group determining means for determining a group of nodes including the first node as a replication transfer range node group when the terminal device enters the area in charge of the first node;
Boundary node determination means for determining, as a boundary node, a node related to a responsible area that forms a boundary of a duplicated transfer area, which is an aggregate of assigned areas of the duplicated forwarding range node group, among the nodes constituting the duplicated forwarding range node group; ,
Information transmitting means for transmitting information indicating the replication transfer range node group and the boundary node to the terminal device;
When the boundary node moves to another assigned area belonging to the replication transfer area, the node associated with the assigned area is a boundary node with reference to the information transmitted by the information transmitting means. And a position registration reception / transfer means for receiving or transferring a position registration request transmitted when the determination is made. The duplicate transfer range node group determining means selects a plurality of second nodes having a service area that is spatially within a predetermined range with the service area of the first node, and the first node And a second node is configured to determine the replication transfer range node group,
The boundary node determination means is configured to determine, as a boundary node, a second node having a responsible area located spatially outermost among the assigned areas. The system according to 6 or 7. 9. The system according to claim 8, wherein the duplication transfer range node group determining unit is configured to determine the duplication transfer range node group in consideration of a moving direction and a moving speed of the terminal device. .

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