JPH09233128A - Inter-network repeater - Google Patents

Abstract

(57) Abstract: An inter-network relay device that reduces the capacity of a storage device and shortens the search time is provided. In an inter-network relay device (1) interconnecting a plurality of networks, when relaying a received frame from a terminal (11) addressed to terminals (12, 13),
A network B that inquires the other device 3 on the network that holds the route information about all the networks about the relay route information of the received frame, and relays the received frame based on the relay route information obtained by this inquiry, Determine C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inter-network relay device that determines a relay route based on route information, and more particularly to an inter-network relay device that reduces a storage device capacity and a search time. .

[0002]

2. Description of the Related Art In order to connect a plurality of networks to each other to form a larger network, an inter-network relay device is provided between the networks. The inter-network relay device needs to relay the received frame to an appropriate network so that the frame on the network reaches the correct destination. For this reason, the inter-network relay device must hold route information for all networks. Since this is required for all inter-network relay devices, all inter-network relay devices must hold route information for all networks.

[0003]

According to such a conventional technique, the route information held by each inter-network relay device becomes enormous in a large-scale network. Therefore, there are problems that (1) the capacity of the storage device (memory) for holding the route information becomes large, and (2) it takes a long time to search the route information.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and provide an inter-network relay device that reduces the storage device capacity and the search time.

[0005]

In order to achieve the above-mentioned object, the present invention provides an inter-network relay device for interconnecting a plurality of networks, which, when relaying a received frame, provides route information for all networks. This is to inquire of another device on the held network about the relay route information of the received frame, and the network to relay the received frame is determined based on the relay route information obtained by this inquiry.

The relay route information obtained by the inquiry may be held for a certain period, and the relay network may be determined based on the held relay route information.

[0007]

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

The inter-network relay device of the present invention comprises means for inquiring other devices about the relay route information of the received frame and means for holding the relay route information obtained by the inquiry for a certain period. The other device to be the inquiry destination is, for example, an inter-upper network relay device belonging to an upper network of a hierarchically configured network, or at least one inter-upstream network relay when the upper and lower levels are determined for a plurality of inter-network relay devices. It is a device. It is assumed that such a relay device between higher networks holds route information for all networks. In this case, the inter-lower-layer network relay device does not hold the route information for all the networks, but may hold the route information for the directly connected networks, for example, only the network identification number.

Since the inter-lower network relay device does not hold the route information, when the route information is needed, such as when relaying a received frame, the inter-lower network relay device holds the route information about all the networks. Queries the relay device for route information. Since the relay device between upper networks holds the route information for all the networks, it can reply the relay route information of the received frame inquired from the relay device between lower networks. The lower-layer inter-network relay device determines a network to relay the received frame based on the relay route information obtained by the inquiry. Therefore, only the inter-upstream network relay device needs to have a storage capacity for holding the route information for all networks, and the inter-lower network relay device does not need the storage capacity for holding the route information. In addition, the time for searching the route information is not required in the lower-layer inter-network relay device.

In the network using the inter-network relay device of the present invention, as shown in FIG. 1, a plurality of networks A, B, C, D and E are mutually connected by inter-network relay devices 1, 2, and 3. Has been done. Of these inter-network relay devices 1, 2, 3 only the inter-network relay device 3 holds the route information for all networks, and the inter-network relay devices 1, 2 are directly connected to their own devices. Holds only the network identification number. These inter-network relay devices 1 and 2 have a function of inquiring the inter-network relay device 3 for route information when route information is required, and a function of storing the relay route information obtained by the inquiry for a certain period. Have

In the network of FIG. 1, the terminal 11 belonging to the network A is the terminal 1 belonging to the network D.
A relay procedure for performing communication with the second party will be described. The terminal 11 transmits a data frame in which a destination address is set to the network D, which is a network different from the network A to which the terminal 11 belongs, to the inter-network relay device 1 to request relay. Since the inter-network relay device 1 does not hold the route information, the relay route information to the network D is unknown. Therefore, the inter-network relay device 3 is queried for relay route information to the network D. On the other hand, the inter-network relay device 3 obtains relay route information based on the route information about all the networks that it holds and responds. That is, the inter-network relay device 3 responds to the inter-network relay device 1 that the inter-network relay device 3 can relay to the network D. Upon receiving this response, the inter-network relay device 1 transmits the relay data addressed to the terminal 13 (data frame from the terminal 11) to the inter-network relay device 3 based on the obtained relay route information.
Relay to The inter-network relay device 3 relays this relay data to the network D. This enables data transmission from the terminal 11 to the terminal 13. Further, since the inter-network relay device 1 stores the relay route information obtained by the inquiry for a certain period, if the relay data to the network D occurs within that period, the inquiry is omitted and the relay is performed immediately. You can Therefore, it is not necessary to make an inquiry every time relay data to the network D is generated.

Next, in the network of FIG. 1, a relay procedure when the terminal 11 belonging to the network A communicates with the terminal 12 belonging to the network B will be described. The terminal 11 transmits a data frame in which a destination address is set to the network B, which is a network different from the network A to which the terminal 11 belongs, to the inter-network relay device 1 to request relay. Since the inter-network relay device 1 does not hold the route information, the relay route information to the network B is unknown. Therefore, the inter-network relay device 3 is queried for relay route information to the network B.
On the other hand, the inter-network relay device 3 obtains relay route information based on the route information about all the networks that it holds and responds. That is, the inter-network relay device 2
Can reply to the network B to the inter-network relay device 1. Upon receiving this response, the inter-network relay device 1 relays the relay data addressed to the terminal 12 (data frame from the terminal 11) to the network C based on the obtained relay route information so as to be transferred to the inter-network relay device 2. The inter-network relay device 2 relays this relay data to the network B. This enables data transmission from the terminal 11 to the terminal 12. Further, since the inter-network relay device 1 stores the relay route information obtained by the inquiry for a certain period, if relay data to the network B occurs within that period,
You can skip the inquiry and start relaying immediately.
Therefore, it is not necessary to make an inquiry every time relay data to the network B is generated.

In the prior art, the inter-network relay devices 1, 2 and 3 of the network shown in FIG. 1 had to hold the route information for all the networks. In addition, the inter-network relay devices 1 and 2 do not hold the route information for all the networks, and need only hold the identification numbers of the networks directly connected to their own devices. Therefore, these inter-network relay devices 1 and 2 do not require a storage capacity for holding the route information. In addition, since the inter-network relay devices 1 and 2 do not search for route information or there is little route information to search, the time for that is also unnecessary or short.

[0014]

The present invention exhibits the following excellent effects.

(1) Since it is not necessary to hold the route information for all networks, the storage capacity for holding the route information can be reduced.

(2) The time for searching the route information is shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a network showing an embodiment of the present invention.

[Explanation of symbols]

 1, 2 Network relay device (lower) 3 Network relay device (upper)

Claims (2)

[Claims] 1. An inter-network relay device for interconnecting a plurality of networks, when relaying a received frame, transmits the received frame to another device on the network that holds route information for all networks. An inter-network relay device, which inquires relay route information, and determines a network to relay the received frame based on the relay route information obtained by this inquiry. 2. The inter-network relay device according to claim 1, wherein the relay route information obtained by the inquiry is retained for a certain period of time, and the relay network is determined based on the retained relay route information.