JP3926495B2 - Mobile communication network system and mobile node management method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transmission device provided in a router (relay device) and a data transmission method in the network in a mobile communication network.
[0002]
[Prior art]
In recent years, the size of computers has been reduced, and computers and terminals (hereinafter referred to as mobile nodes) can be freely moved in a wide area network.
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 “VIP: Protocol providing host mobility transparency, Japan Software Science Society Computer Software, Vol. 10, 4. Fumio Teraoka”.
[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 sends a control packet in which the individual identifier and the position identifier are written to the home router in order to store or update its own entry immediately after the movement. This control packet is transferred to the home router via a plurality of routers (relay devices) on the route to the home router. When receiving the control packet, the plurality of routers (relay apparatuses) add or update the entry of the mobile node to the address conversion table possessed by itself.
[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.
[0006]
Therefore, when a different node communicates with the mobile node via another router (relay device) that does not recognize the destination, it must first pass through the home router. As a result, depending on the scale of the network, a large communication delay is caused, and in the meantime, a large amount of packet loss is caused. This is particularly noticeable when the mobile node moves at high speed or moves frequently.
[0007]
[Means for Solving the Problems]
The present invention adopts the following configuration in order to solve the above points.
<Configuration 1>
A management home router having an address translation memory in which an entry comprising a solid identifier of a node that sends and receives packets to and from each other via a network and a position identifier that indicates the position of the network is stored, and an entry of the address translation memory is added or A mobile node that outputs a control packet including its own identifier and a location identifier indicating the location of the moved network as it moves to update, to the moved network, from the location of the mobile node to the management home router Add or update the individual identifier and position identifier of the received control packet as an entry of the mobile node on its own address translation memory, and regenerate the regenerated packet regenerated from the control packet, located on the route network Suitable for management home router In the mobile communication network system comprising at least one or more route routers to be output and at least one or more non-route routers that are designated as delivery destinations and are not located on the route network, the route router includes: A transmission control unit for transmitting the regenerated packet to the non-route router, and the non-route router receives the individual identifier and the position identifier of the received regenerate packet in an entry of the mobile node on its own address translation memory; A mobile communication network system comprising a conversion control unit for adding or updating as
[0008]
<Configuration 2>
In the mobile communication network system described in Configuration 1, the non-route router includes a transmission control unit that transmits the regenerated packet to at least one or more other routers that are designated as distribution destinations. Has a translation control unit that adds or updates the individual identifier and the position identifier extracted from the received regenerated packet as the entry of the mobile node on its own address translation memory.
[0010]
<Configuration 3 >
A control packet including a mobile node's own individual identifier and a position identifier indicating the position of the moved network as an entry is output to the moved network, and is located on the route network from the position of the mobile node to the management home router The control packet is received by at least one or more route routers, and the individual identifier and location identifier of the control packet are added or updated as an entry of the mobile node in its own address translation memory by the route router, and the route The regenerated packet regenerated from the control packet by the router is output to the management home router, and the solid identifier and the position identifier of the regenerated packet received by the management home router are stored on its own address translation memory. The above mobile node error In the mobile node management method for adding or updating as a tree, the regeneration packet is output from the route router to at least one non-route router designated as a delivery destination, and the reproduction received by the non-route router A method for managing a mobile node, comprising adding or updating a solid identifier and a location identifier of a generated packet as an entry of the mobile node on its own address translation memory.
[0011]
<Configuration 4 >
In the mobile node management method described in Configuration 3, the regenerated packet is output from the non-route router to at least one other router designated as a delivery destination, and received by the other router. The individual identifier and the position identifier of the regenerated packet are added or updated as an entry of the mobile node on its own address translation memory.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the mobile node sends a control packet to the home router immediately after moving. A router on the route to the home router transfers a copy of the control packet (hereinafter referred to as a regenerated packet) to another adjacent router. The other neighboring router that has received the regeneration packet further forwards the regeneration packet toward another router adjacent to itself. This operation is repeated a predetermined number of times.
Therefore, the number of routers that recognize the movement destination of the mobile node increases explosively within a short time.
[0014]
As a result, when a certain node communicates with a mobile node via a router other than the one on the route, the probability of passing through the home router first decreases, and packet loss and communication delay are reduced. In order to achieve the above object, a router includes a data transmission apparatus according to the present invention. The data transmission apparatus according to the present invention includes a control packet distribution table in the network layer of the OSI reference model. This control packet distribution table stores destination entries (items) to which the regenerated packet is transferred.
[0015]
<Specific example configuration>
Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is a block diagram of a data transmission apparatus according to the present invention.
As shown in FIG. 1, the data transmission apparatus according to the present invention 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.
[0016]
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. 2 is an explanatory diagram of an address conversion table.
As shown in FIG. 2, the address conversion table stores an entry (item) including a mobile node individual identifier and a mobile node location identifier.
[0017]
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 consists 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.
[0018]
Returning again to FIG. 1, 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.
[0019]
FIG. 3 is an explanatory diagram of a control packet distribution table.
As shown in FIG. 3, entries (items) of a distribution destination router to which the regenerated packet is transferred are listed. This distribution destination is determined in advance according to the network environment.
Next, the control packet and the regenerated packet will be described with reference to the drawings.
[0020]
FIG. 4 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. 4, 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.
[0021]
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).
[0022]
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.
[0023]
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 number of regenerated packets generated and the location identifier of the router that generated the regenerated packet are described (b). As will be described in detail later, the regenerated packet is regenerated as long as the number of regenerations set in advance based on the size of the network is recognized, that is, while the number is smaller than the threshold. Also, 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.
[0024]
Returning to FIG. 1 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.
[0025]
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.
[0026]
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.
[0027]
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.
[0028]
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.
[0029]
<Operation of specific example>
The operation of the data transmission apparatus according to the present invention will be described including the operation of the mobile node in the network.
FIG. 5 is an operation explanatory diagram of the mobile node.
In FIG. 5, MH represents a mobile node, HR represents a home router, and R1 to R30 represent routers.
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 moves from the position A to the position B will be described with reference to FIGS. Note that the threshold is set to 3 as a precondition.
[0030]
In FIG. 5, when the mobile node MH moves from position A to position B, first, the mobile node MH sends a control packet (FIG. 4 (a)) to the home router MH. At this time, the location B of the transmission source in FIG. 4A describes the location B, and the location identifier of the transmission destination describes the location of the home router HR. At the same time, the mobile node HR is described in the target node individual identifier, and the position B is described in the target node position identifier. The control packet identification information describes the time when the mobile node MH sends out the control packet.
Hereinafter, the packet processing operation will be described with reference to FIG.
[0031]
Step S1
The router R1 (FIG. 5) accepts the control packet from the mobile node MH (FIG. 5).
Step S2
The control unit 5 (FIG. 1) of the router R1 (FIG. 5) refers to the location identifier of the transmission destination and recognizes that it does not coincide with its own location identifier. That is, it recognizes that this packet is a control packet for the home router HR (FIG. 5), and proceeds to step S3.
[0032]
Step S3
The control unit 5 (FIG. 1) of the router R1 (FIG. 5) determines the route to the home router HR (FIG. 5) based on the route table 1 (FIG. 1) managed by itself and sends the control packet to the router R2. Transfer to (FIG. 5) and proceed to step S4.
[0033]
Step S4
The control unit 5 (FIG. 1) of the router R1 (FIG. 5) regenerates packets (see FIG. 1) to all distribution destinations that are determined in advance with reference to the control packet distribution table (FIGS. 1 and 3) managed by itself. 4 (b)) is transmitted. In this regenerated packet (FIG. 4B), adjacent routers (router R6 or router R7 in FIG. 5) are individually described as entries as destination location identifiers. Furthermore, the number of regenerations (here, 1 because it is the first copy) and the location identifier of the copy router (here, the location identifier of R1) are described. The other contents are the same as the control packet. The operation of step S4 will be described again in detail later with reference to other drawings.
[0034]
Step S5
The control unit 5 (FIG. 1) of the router R1 (FIG. 5) adds or updates the target node individual identifier and the target node location identifier to the address conversion table 2 (FIG. 1) 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. 4 (a)) proceeds to router R2 (FIG. 5), and the regenerated packet (FIG. 4 (b)) proceeds to router R6 (FIG. 5) and router R7 (FIG. 5). .
Next, the operation of the regenerated packet (FIG. 4B) that has proceeded to the router R6 (FIG. 5) will be described using FIG. 6 again. The operation of the regenerated packet (FIG. 4B) that has proceeded to the router R6 (FIG. 5) and the operation of the regenerated packet (FIG. 4B) that has proceeded to the router R7 (FIG. 5) are exactly the same. Only the operation of the regenerated packet (FIG. 4B) that has proceeded to R6 (FIG. 5) will be described.
[0036]
Step S1
The router R6 (FIG. 5) accepts the regenerated packet from the router R1 (FIG. 5).
Step S2
The control unit 5 (FIG. 1) of the router R6 (FIG. 5) 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 regenerated packet directed to itself, and proceeds to step S6.
[0037]
Step S6
The control unit 5 (FIG. 1) of the router R6 (FIG. 5) reads the number of regenerations described in the control packet identification information. When this number is equal to or greater than the threshold value of the number of regenerations (three times from the above assumption), the process jumps to step S5. Here, since the number of times of regeneration at the router R1 is only one, the process proceeds to S7.
Step S7
The number of regenerations 2 is described in the control packet identification information of the regeneration packet, and the process proceeds to step S8.
[0038]
Step S8
The control unit 5 (FIG. 1) of the router R6 (FIG. 5) regenerates packets (FIG. 1) to all distribution destinations that are determined in advance with reference to the control packet distribution table (FIGS. 1 and 3) managed by itself. 4 (a)) is sent to step S5. This regenerated packet (FIG. 4B) has the same contents as the control packet except that adjacent routers (router R8 and router R9 in FIG. 5) are described as the destination location identifier. The operation of step S8 will be described again in detail later with reference to other drawings.
[0039]
Step S5
The control unit 5 (FIG. 1) of the router R6 (FIG. 5) adds the target node individual identifier of the mobile node MH (FIG. 5) to the address conversion table 2 (FIG. 1) managed by itself based on the description of the regenerated packet. After adding or updating the target node position identifier, the packet processing operation is terminated.
[0040]
Thereafter, the router R8 (FIG. 5) and the router R9 (FIG. 5) accept the regeneration packet from the router R6 and recognize that the number of regeneration times is two. The regenerated packet (FIG. 4B) is transferred to the router R10 (FIG. 5), the router R11 (FIG. 5), the router R12 (FIG. 5), and the router R13 (FIG. 5) by the same operation as described above.
[0041]
Subsequently, router R10 (FIG. 5), router R11 (FIG. 5), router R12 (FIG. 5), and router R13 (FIG. 5) send regenerated packets from router R8 (FIG. 5) and router R9 (FIG. 5). When accepted, it recognizes that the number of regenerations is three. At this time, the processing operation jumps directly from S6 to step S5.
[0042]
The router R10 (FIG. 5), the router R11 (FIG. 5), the router R12 (FIG. 5), and the router R13 (FIG. 5) store the address conversion table 2 (FIG. 1) managed by itself based on the description of the regenerated packet. After adding or updating the target node individual identifier and the target node location identifier of the mobile node MH (FIG. 5), the packet processing operation is terminated. The range in which this processing operation is completed is represented by a two-dot chain line on FIG. 5 as a threshold three-time region 53 centered on the router R1.
[0043]
During the above operation, the control packet (FIG. 4A) is going through the router R3 (FIG. 5) toward the home router HR (FIG. 5). The control packet (FIG. 4A) continues to be transferred to the home router HR (FIG. 5), and when it arrives at the home router HR (FIG. 5), the address conversion table 2 (FIG. 5) of the home router HR (FIG. 5). In FIG. 1), the entry (item) of the mobile node MH is updated or added to finish its role.
[0044]
Next, the operations in steps S4 and S8 will be described with reference to the drawings.
FIG. 7 is an explanatory diagram of control packet distribution processing operation.
The distribution processing operations in steps S4 and S8 are processed through steps S9 to S12.
Step S9
The control unit 5 (FIG. 1) of each router reads out the entries one by one in order with reference to the control packet distribution table (FIGS. 1 and 3) managed by the router, and proceeds to step S10.
[0045]
Step S10
The process proceeds to step S11 until all entries are read.
Step S11
The control unit 5 (FIG. 1) refers to the control packet distribution table (FIGS. 1 and 3) managed by the control unit 5 and creates a regenerated packet in which the transmission destination is rewritten, and proceeds to step S12.
[0046]
Step S12
The control unit 5 (FIG. 1) transmits the regenerated packet to the rewritten transmission destination, and then returns to step S9 again to repeat the same operation. It transmits regenerated packets for all entries (items) described in the control packet distribution table (FIGS. 1 and 3) managed by itself. Thereafter, the operation is terminated, and the process returns from step S10 to step S4 or S8 in FIG.
[0047]
The operation of the regenerated packet transmitted from the router R1 has been described above by limiting the threshold value three times to the region 53 (FIG. 5). This threshold value three times region 53 (FIG. 5) is formed around all routers on the path of the control packet. All routers in this area will recognize the destination of the mobile node.
For convenience of explanation, the number of entries in the control packet distribution table (FIGS. 1 and 3) is limited to 2 and the threshold for the number of regenerations is limited to 3. This is an example of the present invention, and the number of entries and the number of thresholds can be freely selected according to the scale of the network.
[0048]
Also, depending on the nature of the network, it is possible to increase the number of entries by setting the threshold for the number of regenerations to one.
Furthermore, although the description here is limited to the movement of a mobile node for convenience of explanation, 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.
[0049]
【The invention's effect】
The data transmission apparatus according to the present invention includes a control packet distribution table 3 (FIG. 1). When each router accepts the control packet, the following effects are obtained by forwarding the regenerated packet toward another adjacent router based on the control packet distribution table 3 (FIG. 1).
[0050]
1. When the mobile node moves, the number of routers that recognize the destination of the mobile node increases explosively within a short time.
2. By setting a threshold value for the number of regenerations, the number of routers that recognize the movement destination of the mobile node and the processing time can be freely selected according to the scale of the network.
3. As a result, packet loss and communication delay are less likely to occur.
[Brief description of the drawings]
FIG. 1 is a block diagram of a data transmission apparatus according to the present invention.
FIG. 2 is an explanatory diagram of an address conversion table.
FIG. 3 is an explanatory diagram of a control packet distribution table.
FIG. 4 is an explanatory diagram of a control packet and a regenerated packet.
FIG. 5 is an operation explanatory diagram of a mobile node.
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]
1 Routing Table 2 Address Conversion Table 3 Distribution Table 4 OSI Reference Model 5 Control Unit

Claims (4)

A management home router having an address translation memory storing an individual identifier of a node that sends and receives packets to and from each other via the network and a position identifier indicating a network location, and an entry of the address translation memory is added or A mobile node that outputs a control packet including its own identifier and a location identifier indicating the location of the moved network as it moves to update, to the moved network, from the location of the mobile node to the management home router The regenerated packet located on the route network is added or updated as an entry of the mobile node on its own address translation memory and the regenerated packet regenerated from the control packet is received. Suitable for management home router In a mobile communication network system comprising the at least one or more paths router outputs Te, and at least one or more non-route router not located on the route network is designated as a destination to the route router,
The path router has a transmission control unit that transmits the regenerated packet to the non-path router;
The non-route router has a translation control unit that adds or updates the received identifier of the regenerated packet and the location identifier as an entry of the mobile node on its own address translation memory.
A mobile communication network system characterized by the above. The non-route router has a transmission control unit that transmits the regenerated packet to at least one or more other routers designated as distribution destinations,
The other router has a translation control unit that adds or updates a solid identifier and a location identifier extracted from the received regenerated packet as an entry of the mobile node on its own address translation memory.
2. The mobile communication network system according to claim 1, wherein: A control packet including a mobile node's own solid identifier and a location identifier indicating the location of the moved network as an entry is output to the moved network;
The control packet is received by at least one or more route routers located on a route network from the location of the mobile node to the management home router, and the individual identifier and the location identifier of the control packet are received by the route router as its own address Add or update as an entry of the mobile node on the translation memory, and output the regenerated packet regenerated from the control packet by the route router toward the management home router,
In the mobile node management method, the solid identifier and location identifier of the regenerated packet received by the management home router are added or updated as an entry of the mobile node on its own address translation memory.
Outputting the regenerated packet to at least one non-route router designated as a delivery destination from the route router;
Adding or updating a solid identifier and a location identifier of the regenerated packet received by the non-route router as an entry of the mobile node on its own address translation memory;
A mobile node management method characterized by the above. Outputting the regenerated packet to at least one or more other routers designated as delivery destinations from the non-route router;
Adding or updating the individual identifier and location identifier of the regenerated packet received by the other router as an entry of the mobile node on its own address translation memory;
The mobile node management method according to claim 3, wherein:

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