JPH04341032A - Relay system for multiple address frame - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention applies to LAN communication via a switching network.
The present invention relates to a broadcast frame relay method for mutually relaying broadcast frames between (local area networks).

0002

2. Description of the Related Art Conventionally, in communication between nodes connected to a LAN, the upper layer of the LAN reference model usually uses a network address to recognize the destination.
In LAN media access control, each node is recognized by the address (MAC address) assigned to each node. Therefore, in the lower layer, a method is required to know the MAC address from the network address. Therefore, as a protocol for knowing the MAC address from the above network address, for example, in order to know the MAC address of the destination, the network address of the destination is added to the frame, and the destination of the MAC frame is set as a broadcast address. Each node that has transmitted a broadcast frame and received the broadcast frame performs a transmission procedure in which, when it detects its own network address, it returns a frame with MAC address information added thereto.

[0003] When connecting LANs using a relay device (bridge), data communication cannot be performed between nodes on the LAN with different transmission characteristics (for example, transmission speed, etc.) unless the above-mentioned broadcast frame is relayed. . This is a LAN
The same applies to so-called local bridges that connect LANs between two locations, and so-called remote bridges that connect LANs between remote locations.

[0004] When connecting remote bridges connected to two or more LANs via a switching network,
In order to relay broadcast frames, calls were made, connected, and disconnected for each bridge.

[0005]

[Problem to be solved by the invention] However, multiple LAs
When connecting remote bridges on N via a switched network, calls must be made, connected, and disconnected for each bridge as described above, which increases the transmission delay during relaying and increases the transmission delay. This poses a problem in that the frames transmitted are unnecessary transmissions for unnecessary LANs, and the transmission cost for such unnecessary frames cannot be ignored.

[0006] The present invention was developed in view of the above problems, and involves connecting a plurality of networks in remote locations to each other via a switching network, and relaying frames only to the network to which the transmission destination is connected. The purpose of the present invention is to provide a relay method for broadcast frames that can be broadcast simultaneously.

[0007]

[Means for Solving the Problems] In order to solve the above object, the present invention has a relay device connected to each of a plurality of networks, and each relay device connects to another network which is a transmission destination via a switching network. A broadcast frame having broadcast address information indicating the destination and network address information indicating the transmission destination is transmitted to a relay device connected to the other network, and a response to the broadcast frame is transmitted to the relay device connected to the other network. In a method of relaying broadcast frames received from devices, each relay device has an address table that associates network address information with destination relay devices, and transmits broadcast frames from connected networks. Once captured, a broadcast frame relaying method is provided in which a relay device corresponding to the network address information in the broadcast frame is determined based on the address table, and the broadcast frame is relayed to the relay device.

[0008]

[Operation] Interprets the network address information of the broadcast frame taken from the connected network based on the address table, detects the destination relay device, and transmits the broadcast frame to the destination relay device. will be relayed to. Therefore, by determining the transmission destination to be relayed, unnecessary traffic can be reduced and the broadcast frame can be quickly relayed to the intended transmission destination.

[0009]

Embodiments An embodiment of the present invention will be explained based on the drawings of FIGS. 1 to 3. FIG. 1 is a configuration block diagram showing an embodiment of a bridge device using a frame relay method according to the present invention. In the figure, a LAN side transmitting/receiving section 11 of a bridge device 10 is connected to a LAN 1, receives frames from the LAN 1, and transfers the frames to a forwarding section 13.
At the same time, upon receiving the frame from the forwarding unit 13, the frame is transmitted to the LAN1.

The switching network side transmitting/receiving section 12 relays frames with the switching network side transmitting/receiving section of another bridge device via the switching network A, and upon receiving a frame, sends the frame to the forwarding section 13. . When the forwarding unit 13 receives a frame from the LAN 1, it determines whether the destination address in the frame is a broadcast address or not.
Check whether it is an individual address and decide whether to relay it to another bridge device. At this time, if the destination address is a broadcast address, the forwarding section 13 sends the frame to the broadcast frame processing section 14 . As a result of examining the data section (described later) of the frame in the broadcast frame processing unit 14, if the frame is a broadcast frame for acquiring a MAC address, the source network address is extracted from the data section. , to the address table section 15, and relays the frame to the destination bridge device indicated by the address table section 15. Further, if the frame is not a simultaneous broadcast frame, it is not relayed.

[0011] The broadcast frame processing unit 14 determines whether the captured frame is a broadcast frame for acquiring a MAC address.

0012

[Table 1] As shown in Table 1, the address table unit 15 has an address table that stores network addresses, MAC addresses, and bridge information indicating each bridge device (described later) in association with each other. Search for a network address. When the network address is detected, the corresponding bridge information is sent to the forwarding unit 13. Note that the above address table may be set statically in each bridge device, for example, or each bridge device holds local information and is set by exchanging information between the bridge devices. You may also do so.

FIG. 2 is a block diagram showing an embodiment of the frame structure according to the present invention. In the figure, the frame is
Detection of frame transmission errors and a data section that stores predetermined data including a destination address indicating the destination of the transmission destination, a source address for transmitting this frame, frame length data indicating the length of the frame, and a network address of the source, and frame transmission error detection. It consists of FCS (Frame Check Sequence) for

FIG. 3 shows a LAN using a bridge device that performs frame relay using the frame relay method according to the present invention.
It is a figure which shows the example of a connection. In the figure, LAN1 has
The bridge device 10 and each node 10a to 10c described above are connected to the LAN 2.
20c, the bridge device 30 and each node 30a to 30c are connected to LAN3, and the bridge device 40 is connected to LAN4,
Each node 40a to 40c is connected to each other. Furthermore, the bridge devices 20, 30, and 40 include the bridge device 1
It has the same configuration as 0, and bridge devices 10 to 40
is connected to switching network A. In addition, here, LA
A network layer PDU (Protocol Data) is sent from the node 10a on N1 to the node 30a on LAN3.
The case of transmitting a unit) will be explained.

[0015] When transmitting a network layer PDU, first, the node 10a, in order to know the MAC address,
A simultaneous broadcast frame for acquiring a MAC address, for example, a frame in which all bits of the destination address are "1" and the source address indicates the node 10a, is L.
Send on AN1. When the bridge device 10 receives the frame, its contents are examined. If the received frame is a broadcast frame in which all bits of the destination address are "1", the broadcast frame processing unit 14 examines the data part of the frame. As a result, if the frame is a broadcast frame for acquiring a MAC address, the source network address is extracted from the data section. The address table unit 15 searches the address table shown in Table 1 for the extracted network address. Then, when it is determined that the destination bridge corresponding to the network address is the bridge device 30, the bridge device 10
A call is made to the bridge device 30, which is connected to the bridge device 30 via the switching network A, and a broadcast frame for acquiring a MAC address is relayed to the bridge device 30.

When the bridge device 30 receives the simultaneous broadcast frame, it transmits the simultaneous broadcast frame to the LAN 3. Upon receiving the simultaneous broadcast frame, the node 30a sends a response frame including MAC address information,
For example, if the destination address is an address indicating node 10a,
A frame whose source address indicates node 30a is transmitted to node 10a. In this case, since the connection state has been established between the bridge devices 10 and 30 as described above, the reply packet data indicating the response is returned to the node 10a.

[0017] As a result, the node 10a becomes the node 30
The MAC address of a can be recognized and the network layer PDU
can be transmitted to the node 30a. Therefore, in this embodiment, the relay device interprets the network address information of the broadcast frame taken in from the connected network based on the address table and detects the destination relay device. The destination to which the frame should be relayed can be determined, thereby reducing unnecessary traffic and quickly relaying the broadcast frame to the intended destination.

[0018]

[Effects of the Invention] As explained above, the present invention has relay devices each connected to a plurality of networks,
Each relay device transmits a broadcast frame that has broadcast address information indicating the destination and network address information indicating the destination of the transmission to the destination relay device connected to another network via the switching network. and in a broadcast frame relaying method in which a response to the broadcast frame is received from a relay device of the other network,
Each of the relay devices has an address table that associates network address information with destination relay devices,
When a broadcast frame is fetched from a connected network, the relay device corresponding to the network address information in the broadcast frame is determined based on the address table, and the broadcast frame is relayed to that relay device. , it is possible to connect multiple networks in remote locations to each other via a switched network and relay frames only to the network to which the destination is connected.

[Brief explanation of drawings]

FIG. 1 is a configuration block diagram showing an embodiment of a bridge device using a frame relay method according to the present invention.

FIG. 2 is a configuration diagram showing the configuration of a relayed frame.

FIG. 3 is a diagram showing an example of a LAN connection using a bridge device according to the present invention.

[Explanation of symbols]

1-4 LAN (local area network) 10
a~10c, 20a~20c, 30a~30c, 40a
~40c Nodes 10 to 40 Bridge device 11 LAN side transmitting/receiving section 12 Switching network side transmitting/receiving section 13 Forwarding section 14 Broadcast frame processing section 15 Address table section

Claims (1)

[Claims] Claim 1: A relay device is provided which is connected to each of a plurality of networks, and each relay device transmits information to a relay device connected to another network which is a transmission destination via a switching network.
A broadcast frame that transmits a broadcast frame having broadcast address information indicating a destination and network address information indicating a transmission destination, and receives a response to the broadcast frame from a relay device of the other network. In the relay method, each relay device has an address table that associates network address information with the destination relay device, and when it receives a broadcast frame from the connected network, it receives a broadcast frame based on the address table. 1. A broadcast frame relaying method characterized in that a relay device corresponding to network address information in a broadcast frame is determined by using a multicast frame, and the broadcast frame is relayed to the relay device.