JP4154784B2 - Data transmission method and data transmission router - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transmission method and a data transmission router in a mobile communication network.
[0002]
[Prior art]
As mobile communication networks have become wider, computers and terminals (hereinafter referred to as mobile nodes) mounted on vehicles and the like can move freely within a network spanning a wide area.
The important thing required in this case is that the mobile node obtains the same computer environment regardless of the moved position. In order to solve this problem, various technical developments have been made. For example, it is disclosed in "Design of a transparent communication mechanism for a moving network, Kimio Ishii, Fumio Teraoka, Jun Murai, Proceedings of Multimedia Communication and Distributed Processing Study Group, 1995", etc.
[0003]
In this disclosed technique, a solid identifier that identifies a mobile node and a location identifier that represents the position of the mobile node in the network are used. A plurality of routers (relay apparatuses) arranged in the network possess an address conversion table for storing entries (in this case, items representing the identification and location of mobile nodes) constituted by these identifiers. One of the plurality of routers (relay devices) is selected as the home router. The home router collectively manages mobile nodes in the network.
[0004]
The mobile node transmits a control packet in which a solid identifier and a location identifier are written to the home router in order to store or update its own entry immediately after movement. This control packet is transferred to the home router via another router (relay device) on the route to the home router. When this other router (relay device) accepts the control packet, it adds or updates the entry of the mobile node to its own address translation table.
[0005]
[Problems to be solved by the invention]
By the way, the problems to be solved described below remain in the conventional techniques as described above.
As described above, the router (relay device) that recognizes the movement destination of the mobile node is only the router (relay device) on the path through which the control packet has passed. Further, the router that recognizes the past position of the moving object maintains the past recognition for a long time. As a result, a packet transmitted to the mobile unit is often erroneously transferred to a past position, often resulting in packet loss and communication delay. This is particularly noticeable when the mobile node moves freely in a wide area.
[0006]
[Means for Solving the Problems]
The present invention adopts the following configuration in order to solve the above points.
<Configuration 1>
Mobile node towards a home router that manages the mobile node in the network to move within a predetermined region, in the data transmission method for transmitting a control packet indicating its own position, the router located at the predetermined area, from the mobile node by receiving the control packet is transferred to the control packet toward the home router, and to produce a regenerated packet copy the control packet, the regenerated packet the predetermined area , excluding the lower region of the probability that the mobile node moves, and Rukoto is transferred to other routers adjacent to the self,
A data transmission method characterized by causing the router to register the position of the mobile node based on the control packet and causing the other router to register the position of the mobile node based on the regenerated packet .
[0007]
<Configuration 2>
In data transmission method according to Structure 1, the above other routers by referring to the control packet delivery table which is predetermined by excluding low areas where the probability that the mobile node moves to transfer the regenerated packet A data transmission method characterized by the above.
[0008]
<Configuration 3>
In the data transmission method described in Configuration 2, an area that is excluded from the control packet distribution table and has a low probability of moving a mobile node is selected in advance for each router according to topographical conditions in the predetermined area. A data transmission method characterized by the above.
<Configuration 4>
A data transmission router that receives a control packet indicating the position of the mobile node from a mobile node moving within a predetermined area, and transmits the control packet to a home router for mobile node management, wherein the control packet is copied A packet regenerator for generating a regenerated packet; and determining other data transmission routers that are adjacent to the packet regenerator excluding an area where the mobile node has a low probability of moving within the predetermined area, and the other data transmission routers Further comprising: a transmission control unit that transmits the regenerated packet to register the location of the mobile node; and a location registration unit that registers the location of the mobile node based on the control packet. Transmission router.
<Configuration 5>
The data transmission router according to Configuration 2, further comprising a control packet wiring table for determining the other data transmission router.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the mobile node transmits a control packet to the home router immediately after moving. In a predetermined area, for example, a mobile node mounted on a vehicle or the like transmits a control packet to a home router that collectively manages the mobile nodes in the network. A router (relay device) located in the vicinity of the mobile node accepts the control packet from the mobile node.
[0010]
This router forwards the control packet to a subsequent router on the route toward the home router. Further, a regenerated packet obtained by copying the control packet is created, and the regenerated packet is transferred to another router adjacent to itself within the predetermined area. At this time, the terrain in the region is taken into consideration, and the mobile node is transferred to only the router located in the movable region from the terrain condition.
[0011]
As a result, the probability that a packet is erroneously transferred when another node communicates with a mobile node via a router other than the route to the home router while minimizing the number of entries to which the regenerated packet is distributed. Can be reduced. That is, packet loss and communication delay are reduced. In order to achieve the above object, the data transmission method according to the present invention includes a router provided with a data transmission apparatus described below.
[0012]
<Specific example configuration>
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is an explanatory diagram of a data transmission method according to the present invention.
FIG. 1 is an explanatory diagram for explaining how data is transmitted by a data transmission method according to the present invention in a mobile communication system. Before explaining the data transmission method using this figure, the data transmission apparatus provided in the router used in the present invention will be explained using the figure.
[0013]
FIG. 2 is a configuration diagram of the data transmission apparatus.
As shown in FIG. 2, the data transmission apparatus includes a routing table 1, an address conversion table 2, a control packet distribution table 3, and a control unit 5.
The route table 1 is a memory that displays a packet transmission route based on address information of an accepted packet. That is, it corresponds to a route indicator that indicates the direction in which the packet should travel.
[0014]
The address conversion table 2 is a memory that lists (displays) the position of the mobile node after movement. An example thereof will be described with reference to the drawings.
FIG. 3 is an explanatory diagram of an address conversion table.
As shown in FIG. 3, the address conversion table stores entries (items) each composed of a mobile node individual identifier and a mobile node location identifier.
[0015]
Here, the solid identifier is an identifier used for specifying a mobile node, and the location identifier is an identifier representing a location on a network to which each node belongs. Usually, it is composed of 4 fields of 8 bits according to the IP (Internet Protocol) address system. Each field is expressed in decimal and the fields are separated by a period. For example, it is expressed as 133.149.10.50.
[0016]
Returning again to FIG. 2, the description of the configuration of the data transmission apparatus according to the present invention will be continued. The control packet distribution table 3 is a list that is read when a router receives a control packet, reads a transmission destination of the packet, and transmits a regenerated packet to a router located outside the transmission path. This regenerated packet is obtained by copying the control packet.
An example of the control packet distribution table 3 will be described with reference to the drawings.
[0017]
FIG. 4 is an explanatory diagram of a control packet distribution table.
As shown in FIG. 4, entries (items) of a distribution destination router to which the regenerated packet is transferred are listed. This distribution destination is a list of routers adjacent to itself according to the topography of the predetermined area. That is, a router located in an area where there is a river or the like between adjacent routers and the mobile node is unlikely to move is not selected.
Next, the control packet and the regenerated packet will be described with reference to the drawings.
[0018]
FIG. 5 is an explanatory diagram of the control packet and the regenerated packet.
(A) represents a control packet, and (b) represents a regenerated packet.
Only the portions necessary for the disclosure of the present invention will be described, and the portions not directly necessary for the disclosure of the present invention will be omitted.
As shown in FIG. 5, a source location identifier, a destination location identifier, a target node solid identifier, a target node location identifier, and control packet identification information are written.
[0019]
The location identifier of the transmission source represents the location on the network of the mobile node that transmitted this control packet.
The destination location identifier represents the location of the control packet or the regenerated packet on the destination network. In the case of a control packet, this destination indicates the position of the home router (a). In the case of a regenerated packet, it represents the position of the router listed in the distribution table on the network (b).
[0020]
The solid identifier of the target node specifies a mobile node whose position identifier has been changed by movement.
The location identifier of the target node represents the location on the network of the mobile node whose location identifier has been changed by movement.
An entry in the address conversion table 2 is added or updated based on the target node individual identifier and the target node position identifier.
[0021]
In the control packet identification information, in the case of a control packet, the time (time stamp) at the time of generating the control packet is described (a). Similarly, in the case of a regenerated packet, the time (time stamp) at the time of generating the control packet and the location identifier of the router that generated the regenerated packet are described (b). By describing this position identifier, it is possible to avoid the exchange of regenerated packets between adjacent routers, the mixing of regenerated packets in the path of control packets, and the like.
[0022]
Returning to FIG. 2 again, the OSI reference model 4 of the data transmission apparatus according to the present invention will be described by limiting it to the kernel space (core part).
The routing table 1, the address conversion table 2, and the control packet distribution table 3 described above are arranged in the IP 44 (network layer) of the OSI reference model 4.
[0023]
The system call interface 41 is a part that provides an application program interface (API) to a user space program such as a file input / output function.
The socket 42 is a part that provides a network application program interface (API) such as a function for setting a communication path.
[0024]
The TCP / UDP 43 is a portion where a transport layer protocol such as TCP (Transmission Control Protocol) or UDP (User Datagram Protocol) is mounted.
The IP 44 is a part where a network layer protocol such as IP is implemented. The data transmission apparatus according to the present invention is also mounted in this hierarchy.
The common interface 45 is a part that absorbs differences between devices and allows a plurality of types of network interfaces to be handled in the same way.
[0025]
The network interface 46 is a part where a data link layer protocol such as Ethernet is implemented.
The hardware device driver 47 is a part where a hardware device is mounted.
[0026]
The control unit 5 is a part that controls packet transfer. The control operation described below is controlled by a microprocessor provided in the router according to a program designated in advance. Alternatively, it may be configured by hardware for each individual control operation.
[0027]
<Operation of specific example>
Returning to FIG. 1 again, the data transmission method according to the present invention will be described.
For convenience of explanation, a river flows in a predetermined area. The river has only one bridge in E city. Furthermore, there is a mountain between F city and K city, and traffic is blocked. The description will be made based on the above assumptions.
In FIG. 1, MH represents a mobile node, HR represents a home router, R1 to R11 represent a router, Ls represents a control packet route, Re represents a river, Ma represents a mountain, and Br represents a bridge. . A city to K city represent cities in the area where the communication network is configured.
[0028]
FIG. 6 is an explanatory diagram of packet processing operations.
The processing operation of the control packet and the regenerated packet when the mobile node MH mounted on the vehicle has moved from one of the surrounding cities to the city A will be described with reference to FIGS.
[0029]
In FIG. 1, the mobile node MH mounted on the vehicle first transmits a control packet (FIG. 5A) to the home router HR. At this time, the location identifier of the transmission source in FIG. 5A describes the location of the mobile node MH, and the location identifier of the transmission destination describes the location of the home router HR. At the same time, the mobile node MH is described in the target node individual identifier, and the position of the mobile node MH is described in the target node position identifier. The control packet identification information describes the time when the mobile node MH transmits the control packet.
The packet processing operation will be described below with reference to FIG.
[0030]
Step S1
The router R1 (FIG. 1) receives the control packet from the mobile node MH (FIG. 1).
Step S2
The control unit 5 (FIG. 2) of the router R1 (FIG. 1) refers to the location identifier of the transmission destination and recognizes that it does not match its own location identifier. That is, it recognizes that this packet is a control packet for the home router HR (FIG. 1), and proceeds to step S3.
[0031]
Step S3
The control unit 5 (FIG. 2) of the router R1 (FIG. 1) determines the route to the home router HR (FIG. 1) based on the route table 1 (FIG. 2) managed by itself and sends the control packet to the router R2. Transfer to (FIG. 1) and proceed to step S4.
[0032]
Step S4
The control unit 5 (FIG. 2) of the router R1 (FIG. 1) refers to the control packet distribution table (FIG. 4) managed by the router R1 (FIG. 4) and regenerates the packets (FIG. 5 (b) )). In this regenerated packet (FIG. 5B), the router R10 and the router R11 adjacent to the router R1 (FIG. 1) are described as individual entries as the location identifier of the movement destination.
[0033]
It should be noted that router R4 (FIG. 1) and router R5 (FIG. 1) are both adjacent to router R1 (FIG. 1), but are not listed in the control packet distribution table (FIG. 4). That is. That is, there is a river between the router R1 (FIG. 1) and the router R4 (FIG. 1) and the router R5 (FIG. 1). Accordingly, the mobile node MH has moved from the D city (FIG. 1) managed by the router R4 (FIG. 1) and the B city (FIG. 1) managed by the router R5 (FIG. 1), or moved thereafter. Probability is also low. Therefore, it is not necessary to update or add to the address conversion table 2 (FIG. 2) of the router R5 (FIG. 1) and the router R4 (FIG. 1).
The operation of step S4 will be described in detail later again with reference to other drawings.
[0034]
Step S5
The control unit 5 (FIG. 2) of the router R1 (FIG. 1) adds or updates the target node individual identifier and the target node location identifier to the address conversion table 2 (FIG. 2) managed by itself based on the description of the control packet. After that, the packet processing operation is terminated.
[0035]
At this point, the control packet (FIG. 5A) is transferred to the router R2 (FIG. 1), and the router R2 (FIG. 1) advances the control packet (FIG. 5A) from the router R1 (FIG. 1). When accepted, the control packet (FIG. 5 (a)) is transferred to the router R3 (FIG. 1) by repeating the same operation as described for the router R1 (FIG. 1).
[0036]
The router R2 (FIG. 1) does not include the router R9 (FIG. 1) located in the city K (FIG. 1) where traffic is blocked by the mountain Ma (FIG. 1). On the other hand, since the river Re (FIG. 1) has a bridge Br (FIG. 1) and is movable to E city (FIG. 1), the router R6 (FIG. 1) located in E city (FIG. 1) is described. . Therefore, the regenerated packet (FIG. 4B) is transmitted.
Similarly, the router R3 (FIG. 1) transfers the control packet (FIG. 5A) to the home router HR (FIG. 1).
[0037]
The packet processing operation of the home router HR (FIG. 1) will be described using FIG. 6 again.
Step S1
The home router HR (FIG. 1) accepts the control packet (FIG. 5 (a)) from the router R3 (FIG. 1).
[0038]
Step S2
The control unit 5 (FIG. 2) of the home router HR (FIG. 1) refers to the location identifier of the transmission destination and recognizes that it matches the own location identifier. That is, it recognizes that this packet is a control packet for the home router HR (FIG. 1) and jumps to step S5.
[0039]
Step S5
The control unit 5 (FIG. 2) of the home router HR (FIG. 1) adds the target node individual identifier of the mobile node MH (FIG. 1) to the address conversion table 2 (FIG. 2) managed by itself based on the description of the control packet. After adding or updating the target node position identifier, the packet processing operation is terminated.
[0040]
Next, the operation in step S4 will be described with reference to the drawings.
FIG. 7 is an explanatory diagram of control packet distribution processing operation.
The distribution processing operation in step S4 is processed through steps S6 to S9.
Step S6
The control unit 5 (FIG. 2) of each router refers to the control packet distribution table managed by itself and sequentially reads out one entry at a time and proceeds to step S7.
[0041]
Step S7
The process proceeds to step S8 until all entries are read.
Step S8
The control unit 5 (FIG. 2) refers to the control packet distribution table managed by itself, creates a regenerated packet with the destination rewritten, and proceeds to step S9.
[0042]
Step S9
The control unit 5 (FIG. 2) transmits the regenerated packet to the rewritten transmission destination, and then returns to step S6 again to repeat the same operation. Regenerate packets for all entries (items) described in the control packet distribution table managed by the device itself are transmitted. Thereafter, the operation is terminated, and the process returns from step S7 to step S4 in FIG.
[0043]
For convenience of explanation, the description is limited to the mobile node mounted on the vehicle. However, the present invention is not limited to this, that is, the movement may be performed on foot, and is not necessarily on the road. It is not necessary. That is, a case where a pedestrian carries a mobile node from one building to another building having a different router is included.
Furthermore, although the description has been limited to the movement of the mobile node, the present invention is not limited to this.
That is, the same can be applied to a sub-network composed of a plurality of nodes.
[0044]
【The invention's effect】
As described above, the router obtains the following effects by describing the entries of adjacent routers in the control packet distribution table provided for the router, excluding areas where the mobile node is unlikely to move.
1. Unnecessary regeneration of the regenerated packet can be limited.
2. The entry before movement can be updated within a short time with the minimum number of regenerated packets.
3. As a result, packet loss and communication delay can be reduced efficiently.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a data transmission method according to the present invention.
FIG. 2 is a configuration diagram of a data transmission apparatus.
FIG. 3 is an explanatory diagram of an address conversion table.
FIG. 4 is an explanatory diagram of a control packet distribution table.
FIG. 5 is an explanatory diagram of a control packet and a regeneration packet.
FIG. 6 is an explanatory diagram of a packet processing operation.
FIG. 7 is an explanatory diagram of control packet distribution processing operation;
[Explanation of symbols]
City A to City K City HR Home router Ls Control packet route Ma Mountain MH Mobile nodes R1 to R11 Router Re River

Claims (5)

In a data transmission method in which a mobile node that moves in a predetermined area toward a home router that manages a mobile node in a network transmits a control packet that represents its own position ,
A router located in said predetermined area,
Wherein the mobile node by receiving the control packet is forwarded towards the control packet to the home router, and the control packet to generate regenerated packet copying, the regenerated packets at the predetermined area , excluding the lower region of the probability that the mobile node moves, and Rukoto is transferred to other routers adjacent to the self,
Causing the router to register the location of the mobile node based on the control packet and causing the other router to register the location of the mobile node based on the regenerated packet;
A data transmission method characterized by the above. The data transmission method according to claim 1, wherein
Data transmission method, wherein the other router, and transfers the reference to the regenerating packet control packet delivery table which is predetermined by excluding low areas where the probability of the mobile node moves. In the data transmission method according to claim 2,
A data transmission method characterized in that an area that is excluded from the control packet distribution table and has a low probability of moving a mobile node is selected in advance for each router according to topographical conditions in the predetermined area. A data transmission router that receives a control packet indicating a position of the mobile node from a mobile node that moves within a predetermined area, and transmits the control packet to a home router for mobile node management,
A packet regeneration unit for copying the control packet and generating a regeneration packet;
In order to determine other data transmission routers that are adjacent to the mobile node except for areas where the mobile node has a low probability of moving within the predetermined area and to register the position of the mobile node in the other data transmission router A transmission control unit for transmitting the regenerated packet;
A location registration unit that registers the location of the mobile node based on the control packet;
A data transmission router comprising: The data transmission router according to claim 4, wherein
A data transmission router further comprising a control packet wiring table for determining the other data transmission router.

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