JP3125349B2 - Network system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system for communicating data, and more particularly to determining a communication path in a network system.

[0002]

2. Description of the Related Art This type of network system has a logical configuration as shown in FIG. 5, for example. In the figure,
Each terminal device E11, E12 is connected to the network A,
Each terminal device E21, E22 is connected to the network B,
A terminating device E31 is connected to the network C. The management device R11 is connected to the network A and the network B, and connects these networks with the shortest route. Further, the management device R12 is connected to the network A and the network C, and connects these networks by the shortest route.

Here, for example, when data is to be communicated from the terminal device E11 to the terminal device E21, the terminal device E11
Requests the relay to the management device R11 that connects the networks A and B by the shortest route, and transmits the data to the terminal device E21 through the management device R11.

In order to communicate data by the shortest route, the terminating device stores the shortest route from the network to which the device is connected to each of the other networks, and stores the shortest route in the destination other terminating device. The shortest route is appropriately selected in response to the request, and the management device that provides the selected shortest route is requested to relay data. The shortest route between such networks is obtained on the management device side, and is broadcast as routing information from the management device to each terminal device. Further, since the logical configuration of the network system is not permanent and changes as needed, the routing information is updated one by one and is broadcast periodically. Therefore, each terminal device receives the routing information periodically, and stores and manages the latest routing information.

However, when the scale of the network system is enlarged or complicated, the amount of routing information becomes very large. Therefore, a storage area for storing the routing information is secured by the terminal device. It will be difficult to do.

Therefore, a routing information management processing method has been proposed in which a necessary route is extracted from the routing information sent from the management device by a terminating device, and only the extracted route is stored and managed (Japanese Patent Laid-Open No. Hei 2 (Hei) 2). -143
No. 746).

However, in this case, if an accurate route is not stored, the terminating device waits for the periodic reception of the routing information, so that there is a disadvantage that it takes time to transmit data.

[0008]

As described above, in the conventional network system, when the scale of the network system is expanded or complicated, the amount of routing information becomes very large. There is a problem that it becomes difficult to secure a storage area for storing the data by the terminal device. Japanese Patent Application Laid-Open No. 2-143746 discloses a technique in which only a necessary route extracted from routing information is stored in the terminating device. However, if an accurate route is not stored, the terminating device is not stored. Has a disadvantage that it takes a long time to transmit data because it waits for periodic reception of routing information.

Therefore, the present invention provides a network system capable of promptly selecting a management device capable of providing the shortest route of data communication from each management device without storing routing information on the terminal device side. The purpose is to provide.

In order to achieve the above object, the present invention comprises a plurality of terminating devices connected to a plurality of networks, respectively, and a plurality of management devices for relaying data transmitted between the terminating devices, In a network system, the management device has a routing table for managing routing information between the terminal devices, and broadcast-transmits routing information including an address of the management device managed by the routing table to the plurality of terminal devices, A routing information receiving unit that receives routing information broadcast-transmitted from the management device; and an address that extracts and stores an address of the management device included in the routing information received by the routing information reception unit. Storage means; Relay request means for requesting a management device corresponding to the address stored in the address storage means to relay data transmission to a desired data transmission destination, wherein the management device performs a relay request by the relay request means. Route determining means for determining an optimal data transmission route for the desired data transmission destination with reference to the routing table, and if the optimal data transmission route determined by the determining means cannot be provided, the determined optimal Transmission means for transmitting routing information to another management device that can provide a suitable data transmission route to the terminal device that has requested the relay.

According to the present invention, the management device having the routing table for managing the routing information between the terminal devices broadcasts the routing information including its own address, and performs the routing at the time of the relay request of the data transmission from the terminal device. If the optimum transmission route for the data transmission destination is determined with reference to the table and the determined transmission route cannot be provided, the terminating device that requests the relay of the routing information to the management device capable of providing the optimum transmission route , The terminal device only stores and manages the address of each management device, and the storage area for this purpose is clearly smaller than the area for storing the routing information. Further, since the data relay is requested to the management device having the address selected from the stored addresses, it does not take much time to transmit the data.

[0012]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a management apparatus to which an embodiment of the network system according to the present invention is applied, and FIG. 2 shows a terminating apparatus to which an embodiment of the network system according to the present invention is applied. I have. The management device of this embodiment is applied to each of the management devices R11 and R12 in the network system shown in FIG. 5, and the termination device of this embodiment is each of the termination devices E11 and E11 in the network system shown in FIG. , E12, E21, E22, E31
Can be applied to any of the above.

In the management device shown in FIG.
Numeral 1 is connected to each of the networks 12 and 13 for transmitting and receiving packets to and from these networks.

The routing table 14 stores routing information, and the routing information stores the shortest route for relay provided by the management device,
That is, it indicates the route between the networks 12 and 13 and the shortest route for relay provided by another management device.

The control unit 15 is for controlling the management device, and includes a shortest route determination unit 16 and a route notification unit 17.

Note that the logical configuration of the network system shown in FIG. 5 changes at any time, and therefore the shortest routes that can be provided by each management device also change, so that each time the logical configuration of the network system changes. Each of the management apparatuses transmits and receives each piece of routing information indicating the shortest route, thereby updating the routing information in the routing table of each management apparatus.

Next, in the terminating device shown in FIG. 2, an address indicating the terminating device and an address indicating broadcast communication are stored in the reception address storage unit 21.

The receiving section 22 is connected to the network 23 and takes in packets on the network 23. When receiving the packet, the receiving unit 22 checks the destination address included in the packet with each address in the received address storage unit 21. If the destination address included in the packet matches one of the addresses in the received address storage unit 1, the packet is destined for the terminating device, and the receiving unit 22 converts the packet to the packet processing unit. Give 24. The destination address included in the packet is stored in the received address storage unit 21.
If the address does not match any of the addresses, the receiving unit 22 discards the packet because the packet is not addressed to the terminating device.

The packet processing unit 24 is for processing a given packet. For a packet including an address indicating the terminating device as a destination address, first determine whether the packet includes routing information. Is determined, and if the packet does not include the routing information, appropriate processing is performed on the packet. If the packet includes the routing information, the packet is provided to the address determination unit 25. In addition, for a packet including an address indicating a broadcast as a destination address, it is first determined whether or not the packet includes routing information. If the packet does not include routing information, an appropriate Processing is performed, and if the packet contains routing information, the packet is given to the management address extracting unit 26.

When the management address extracting unit 26 receives a packet containing routing information from the packet processing unit 24 and includes an address indicating broadcast as a destination address, the source address contained in the packet, that is, the management device Is extracted, and this address is stored in the first management address storage unit 27.

When a packet including routing information is given from the packet processing unit 24 to the destination including the address indicating the terminating device as the destination address, the address determining unit 25 determines the address of the management device that provides the route indicated by the routing information. And the address of the management device is stored in the second management address storage unit 28.

The transmitting unit 29 receives a packet to be transmitted from the packet processing unit 24 and sends the packet to the network 23.

In the terminating device having such a configuration, if the terminating device is, for example, the terminating device E11 shown in FIG. 5, a packet including routing information from each of the management devices R11 and R12 to the network A is periodically transmitted. Each time the data is transmitted, the processing of the flowchart shown in FIG. 3 is performed. Note that the periodically transmitted packet is broadcast to all the terminating devices connected to the network A, and includes an address indicating the broadcast as a destination address. Hereinafter, it is referred to as a broadcast packet.

First, assuming that a broadcast packet is transmitted from the management device R11 to the network A, the receiving unit 22 in the terminal device E11 fetches the broadcast packet from the network A (step 10).
1) It is determined whether or not the destination address included in the broadcast packet matches any of the addresses in the reception address storage unit 21 (step 10).
2). Here, since the address indicating the broadcast is included in the broadcast packet as the destination address, it is determined that they match (step 102, YES), and the broadcast packet is given to the packet processing unit 24. If the destination address included in the packet does not match any of the addresses in the received address storage unit 21 (step 102, NO), the packet is discarded (step 103), and the end is determined. Become.

When receiving the broadcast packet, the packet processing unit 24 confirms that the broadcast address is included (step 104, YES) and also confirms that the routing information is included (step 105, step 105). YES), after which the broadcast packet is given to the management address extracting unit 26. If the broadcast address is not included (step 104, NO),
If routing information is not included (step 10
5, NO), and other processing is performed on this packet (step 106).

When receiving the broadcast packet, the management address extracting unit 26 extracts the address of the management device R11 included in the packet as the source address (step 107), and stores this address in the first management address storage unit 27. (Step 108).

The same processing is performed when a broadcast packet is sent from the management device R12 to the network A, whereby the address of the management device R12 is stored in the first management address storage unit 27.

When the broadcast packet from the management device is received in this way, the routing information contained in this packet is not stored at all, and only the address of the management device contained in this packet is stored in the first management address storage unit 27. I try to remember.

The management device indicated by the address stored in the first management address storage unit 27 relays the packet from the terminal device E11 connected to the network A to the terminal device connected to another network. It is possible. That is, here, the management devices that can relay the packet from the terminal device E11 to the terminal device connected to another network are the management devices R11 and R12, and the addresses of these management devices R11 and R12 are the first. Will be stored in the management address storage unit 27 of

Note that the logical configuration of the network system shown in FIG. 5 changes at any time, so that a packet is relayed from the terminating device E11 connected to the network A to the terminating device connected to another network. Since a possible management device also changes, the address is erased from the first management address storage unit 27 after a certain period of time, which is the transmission period of the broadcast packet, has elapsed since the address was stored in the first management address storage unit 27. To do it. As a result, the first management address storage unit 27 does not store the address of the management device that cannot relay the packet due to a change in the logical configuration of the network system. Only the device address will be stored.

Next, in a state where the addresses of the management devices R11 and R12 are stored in the first management address storage unit 27, the terminating device E11 connected to the network A
The procedure for transmitting a packet from the network to a terminating device connected to another network will be described with reference to the flowchart shown in FIG. The destination terminal device is a terminal device E21 connected to the network B.

First, when a request for transmitting a packet addressed to another terminal device E21 occurs (step 201), the packet processing unit 24 in the terminal device E11 changes the address of the management device that provides the shortest route to the destination terminal device E21. It is determined whether or not it is already stored in the second management address storage unit 28 (Step 202). Here, since the address of the management device that provides the shortest route to the destination terminating device E21 is not stored in the second management address storage unit 28 (Step 202, NO), the packet processing unit 24 performs the first processing. One of the addresses of the management devices R11 and R12 in the management address storage unit 27 is read (step 203).

Here, it is assumed that the read address is the address of the management device R12, and the address of the management device R12 that cannot provide the shortest route from the terminal device E11 to the destination terminal device E21 is read. .

When reading the address of the management device R12, the packet processing unit 24 includes the address of the management device R12,
Further, it forms a packet addressed to the terminating device E21 in the network B, and sends this packet to the network A via the transmitting unit 29 (step 204).

In the management device R12, the relay unit 11 captures the packet, and the relay unit 11 determines whether the packet includes an address indicating the management device. Here, if this address is included, this packet has been requested to relay to the management device, and is therefore passed from the relay unit 11 to the control unit 15 (step 30).
1, YES). If this address is not included, the packet is not requested to relay to the management device (step 301, NO), and no processing is performed.

When receiving the packet from the relay unit 11, the control unit 15 extracts destination data indicating the terminating device E21 in the network B from the packet, and obtains a route to this destination based on the routing information in the routing table 14. (Step 302). Here, the route from the management device to the terminating device E21 in the network B is such that a packet is once delivered to another management device R11, and the packet is transmitted from the other management device R11 to the network B. Is required.

Next, the shortest route determination unit 16 is activated,
The shortest route determination unit 16 determines whether the route obtained in step 302 is the shortest route (step 303). That is, source data and destination data are extracted from the packet, and the shortest route from the source network A indicated by the source data to the destination network B indicated by the destination data is determined based on the routing information in the routing table 14. Ask for
It is determined whether or not the shortest route matches the route obtained in step 302. Here, the shortest route is a route from the network A to the network B via the other management device R11, and the route obtained in the step 302 once passes the packet to the other management device R11 and passes the packet to another management device R11. Since the route is sent from the management device R11 to the network B, that is, the route from the network A to the network B via the management device R12 and the other management device R11, the shortest route is the route determined in the step 302. (Step 303, NO). In this case, the route notification unit 17 is activated.

The route notifying section 17 forms routing information indicating the shortest route from the network A to the network B via the other management device R11, and further includes a source address included in a packet from the terminal device E11,
That is, the address of the terminating device E11 is extracted, a packet including the address of the terminating device E11 as a destination address and including routing information is formed, and the packet is transmitted to the network A (step 304).

Thereafter, the control unit 15 executes step 302
In order to relay the packet from the terminating device E11 on the route determined in the above, the packet is sent from the relay unit 11 to the network A and transferred to another management device R11. When receiving the packet, the other management device R11 sends the packet to the network B. The destination terminating device E21 confirms that the address of the terminating device is included as the destination address, and fetches this packet.

If it is determined in step 303 that the shortest route matches the route obtained in step 302, the process jumps to step 304 and ends.

On the other hand, the receiving unit 22 in the terminal device E11 of the transmission source fetches the packet from the management device R12, and the destination address included in this packet, that is, the address of the terminal device is stored in the received address storage unit 21 as the address of each address. After confirming that the packet matches one of them, this packet is given to the packet processing unit 24.

The packet processing unit 24 provides the packet to the address determination unit 25 because the packet includes the address indicating the terminating device as the destination address and also includes the routing information. Upon receiving the packet, the address determination unit 25 determines the address of the management device R11 based on the routing information included in the packet, that is, the routing information indicating the shortest route from the network A to the network B via another management device R11. Then, the address of the management device R11 is stored in the second management address storage unit 28 as providing the shortest route (step 205).

The management device R12 requested to relay in this way.
Although it cannot provide the shortest route, it relays the packet from the terminating device E11 on a route that can be provided by itself, and notifies the terminating device E11 of routing information indicating the shortest route. In addition, the termination device E11
Calculates the address of the management device R11 that can provide the shortest route based on the routing information, and stores the address of the management device R11 in the second management address storage unit 28.

When the packet addressed to the terminating device E21 is transmitted again, the processing from step 201 is performed again. However, in step 202, the management device that provides the shortest route to the destination terminating device E21 Since it is determined that the address of the management device R11 has already been stored in the second management address storage unit 28 as the address of the above, step 203 is omitted, and instead, step 2 is performed.
06 will be performed. In this step 206, the packet processing unit 24 sets the second management address storage unit 2
8, the address of the management device R11 is read out, and a packet containing the address of the management device R11 and addressed to the terminating device E21 in the network B is formed. Then, this packet is transmitted to the network A via the transmission unit 29 (step 204). This packet is relayed by the management device R11, sent out to the network B, and taken in by the terminating device E21.

Since the logical configuration of the network system changes at any time, the management device R11 may not provide the shortest route. In such a case, the routing information for providing the shortest route is notified from the management device R11 to the terminating device E11 (steps 303 and 304), and in response to this, the address in the second management address storage unit 28 is responded. May be updated (step 205). The address of each management device capable of relaying a packet in this way is stored in the first and second management address storage units 27 and 28, and when transmitting a packet, any one of the addresses of each management device is used. Is selected, and a relay is requested to the management device having the selected address. That is, when transmitting a packet, the packet is immediately transmitted to a management device that can perform relaying, instead of waiting for the periodic reception of the broadcast packet. Also, instead of the routing information, the address of each management device capable of relaying a packet is stored, so that the storage area for this is small.

[0047]

As described above, according to the present invention, the address of each management device is stored, and when transmitting data to the network, one of these addresses is selected and selected. Since the relay of the data is immediately requested to the management device having the address, the time is not required until the data is transmitted. Also, there is no need to store the routing information, only the address of each management device is stored instead.
The storage area can be small.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a management apparatus to which an embodiment of a network system according to the present invention is applied.

FIG. 2 is a block diagram showing a termination device to which an embodiment of the network system according to the present invention is applied;

FIG. 3 is a flowchart showing a broadcast packet receiving process performed in the terminal device shown in FIG. 2;

FIG. 4 is a flowchart showing a packet relay process performed by the management device shown in FIG. 1 and the terminating device shown in FIG. 2;

FIG. 5 is a diagram illustrating a logical configuration of a network system.

[Explanation of symbols]

11 relay unit, 12, 13 network, 14 routing table, 15 control unit, 16 shortest route determination unit, 17 route notification unit, 21 reception address storage unit, 22 reception unit, 23 network 24 packet processing unit, 25 address determination unit, 26 management address extraction unit, 27 first management address storage unit, 28 second
, A management address storage unit, 29... A transmission unit.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/66 H04L 12/28 H04L 12/56 H04L 12/40 H04L 12/42 H04L 12/46

Claims (1)

(57) [Claims] A plurality of terminating devices connected to a plurality of networks; and a plurality of management devices for relaying data transmitted between the terminating devices, wherein the management device is configured to route between the terminating devices. In a network system having a routing table for managing information and broadcasting transmission of routing information including an address of the management device managed by the routing table to the plurality of terminal devices, the terminal device broadcasts from the management device. Routing information receiving means for receiving the transmitted routing information; address storage means for extracting and storing the address of the management device included in the routing information received by the routing information receiving means; and storing in the address storage means To the address given Relay request means for requesting a corresponding management apparatus to relay data transmission to a desired data transmission destination, wherein the management apparatus refers to the routing table when the relay request is made by the relay request means, and Route determining means for determining an optimal data transmission route for a desired data transmission destination; and when the optimal data transmission route determined by the determining means cannot be provided, the determined optimal data transmission route can be provided. Transmitting means for transmitting the routing information to the management device to the terminal device which has requested the relay.