JPH09200246A - Multiport bridge - Google Patents

Abstract

(57) Abstract: A multi-port bridge capable of complex frame processing and having a large communication capacity is provided. A microcomputer unit 400 performs a relay process of a broadcast frame or a multicast frame by a software process, and a unicast frame relay unit 500 configured by a dedicated logic circuit performs a relay process of a unicast frame. For this reason, the received frame determination units 301 to 303 determine, from the frame destination information, whether the received frames of the network interfaces 201 to 203 are broadcast frames, multicast frames, or unicast frames. Either the cast frame relay unit 500 is selected and transferred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-port bridge which interconnects a plurality of networks to relay a frame, and more particularly to a multi-port bridge capable of complex frame processing and having a large communication capacity. is there.

[0002]

2. Description of the Related Art In a recent LAN, especially a LAN using IEEE802.3 called Ethernet,
The use of multi-port bridges (also called switching hubs) with multiple ports is increasing. FIG. 2 shows a configuration example of the multiport bridge. The multi-port bridge is composed of a plurality of network interfaces 21 to 23 that form ports and a microcomputer unit 40 that performs relay processing by software.
Frames can be relayed between network interfaces. The microcomputer unit 40 is
It is composed of a microcomputer, memory, and peripheral circuits.

This multi-port bridge was originally developed for the purpose of increasing the communication capacity, but recently, as a device capable of realizing a virtual LAN by forming logical groups or segments that are not restricted by physical wiring. Attention has been paid.

For example, when connecting terminals of a protocol used only in one department and terminals of a protocol used all over the place to the same wiring (segment), conventionally, fine management of network addresses or The setting had to be changed every time the terminal was moved to another segment, but in the virtual LAN using the logical segment, the management is simplified and can be realized only by setting the multiport bridge. This is the destination address, source address,
It is realized by analyzing information such as protocols and limiting the relay ports. If this function is developed, various applications are possible, such as changing the group structure for each protocol used and allowing one terminal to belong to a plurality of groups for each protocol.

However, the more the virtual LAN function is enhanced, the longer it takes for the microcomputer unit 40 to process a frame in the multi-port bridge, and another problem is that the communication capacity is increased. there were.

[0006] Conventionally, as a means for solving this problem, it has been considered that a dedicated circuit for frame processing is provided to speed up the processing to prevent the sacrifice of communication capacity. An example is shown in FIG. In the multi-port bridge of FIG. 3, the dedicated circuit 80 performs frame relay processing between the network interfaces 21 to 23, and the microcomputer unit 40 controls it.

[0007]

However, the conventional method has a problem in that the frame processing dedicated circuit 80 becomes complicated. For example, in a logically configured segment, communication limited to the segment may be performed. Broadcast (broadcast) is to send a frame to all terminals in a logical segment, and multicast (group broadcast) is to send a frame to all terminals having a common group address. Broadcast frames and multicast frames have to be selectively relayed to a plurality of ports, and are handled differently depending on the protocol, which is a factor of increasing the complexity and scale of the circuit. Therefore, there are economic demerits such as an increase in size of the device due to an increase in the size of the circuit, an increase in power consumption, and an increase in manufacturing cost. Moreover, since the frame processing method is fixed in the circuit, it is difficult to expand or add the function.

As described above, in the conventional techniques shown in FIGS. 2 and 3,
Virtual LA without compromising communication capacity and expandability
It was difficult to construct N.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve the above problems and provide a multi-port bridge capable of complex frame processing and having a large communication capacity.

[0010]

In order to achieve the above object, the present invention provides a relay process for a broadcast frame and a multicast frame in a multi-port bridge having a plurality of network interfaces and relaying frames between these network interfaces. And a unicast frame relay unit that only relays unicast frames, and selectively transfers the received frame of each network interface to either the microcomputer unit or the unicast frame relay unit. The reception frame determination unit is provided.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The main point of the present invention is that a microcomputer unit performs a relay process of a broadcast frame or a multicast frame by a software process, and a unicast frame dedicated to the relay process of a unicast frame is constituted by a unicast It is what the frame relay unit does. For this purpose, the reception frame judgment unit judges whether the reception frame of each network interface is a broadcast frame, a multicast frame, or a unicast frame from the destination information of the frame, and either the microcomputer unit or the unicast frame relay unit. Select and transfer.

An embodiment of the present invention is shown in FIG. The multi-port bridge 100 includes a plurality of network interfaces 201 to 203 and a reception frame determination unit 3 corresponding to each network interface.
01 to 303, a microcomputer unit 400 for relaying broadcast frames and multicast frames, and a unicast frame relay unit 500 for only relaying unicast frames.

Received frame determination units 301-303
Can selectively transfer the received frame to either the microcomputer unit 400 or the unicast frame relay unit 500 based on the destination information of the frame received by the corresponding network interface. Microcomputer unit 4
00 is operated by software, and virtual LA
In order to realize N, it has a function of analyzing the information such as the destination address, the source address, and the protocol of the received frame and limiting the port for relaying, and is capable of relaying broadcast frames and multicast frames. The unicast frame relay unit 500 is composed of a logic circuit and has a function necessary to relay only a unicast frame.

The operation of the multiport bridge 100 will be described.

When one terminal on the network communicates with another terminal, first, the MAC address of the other terminal is investigated using a broadcast frame or a multicast frame. This is because the address for recognizing the other party in the protocol is different from the MAC address, and therefore the MAC address of the other party needs to be known first for communication.

The terminals 601, 602 and 603 are respectively
Network interfaces 201, 202, 203
Network interface 20
1 and the network interface 202 are set in the same logical segment. TCP / IP is assumed as the protocol.

When the terminal 601 communicates with the terminal 602, the terminal 601 first transmits a broadcast frame.

The network interface 201 is
Upon receiving the broadcast frame from the terminal 601, the received frame is transferred to the received frame determination unit 301. Therefore, the transfer destination is determined depending on whether the frame is a unicast frame. Since this frame is a broadcast frame, it is transferred to the microcomputer unit 400. Microcomputer unit 4
At 00, the relay destination is determined based on the preset logical segment, and the frame is transferred to the network interface 202. Network interface 2
02 transmits the frame to the terminal 602.

At this time, at the same time, the microcomputer unit 400 registers the MAC address of the terminal 601 in the unicast frame relay unit 500 as information of the terminal connected to the network interface 201.

The terminal 602 that has received the broadcast frame transmits a unicast frame to the terminal 601 in order to notify the MAC address of its own station. When the network interface 202 receives this unicast frame, the reception determination unit 302 transfers it to the unicast frame transfer unit 500. The unicast frame transfer unit 500 transfers this frame to the network interface 201 based on the MAC address of the terminal 601 registered previously. The network interface 201 transmits the frame to the terminal 601. When the unicast frame arrives at the terminal 601, the terminal 601 can know the MAC address of the terminal 602.

After that, the terminals 601 and 602 can communicate with each other using a unicast frame.

When communication is attempted from the terminal 601 to the terminal 603, the following occurs. The broadcast frame from the terminal 601 is relayed as before, but this frame is not relayed because the network interface 203 is not set as the same logical segment. Since the broadcast frame does not reach the terminal 603, the terminal 601 cannot know the MAC address of the terminal 603.

As described above, the logical group (segment) can be formed by performing the protocol determination processing on the broadcast frame and the multicast frame. In this case, since it is not necessary to perform the protocol determination for the unicast frame, it is possible to simplify the circuit by deleting the protocol determination function from the unicast frame relay unit 500.

In the description of the present embodiment, TCP / IP is assumed as the protocol, but the same applies to other protocols to use the broadcast frame or the multicast frame to know the MAC address. Virtual LA if managed
N can be realized.

In the embodiment shown in FIG. 1, a 3-port multi-port bridge is used for simplification.
There are no problems with 4 or more ports. Further, for the sake of explanation, each circuit is expressed as an individual circuit, but it is also possible to realize a plurality of functions by one integrated circuit.

As described above, according to the present invention, since the complicated frame processing by the microcomputer and the high-speed frame processing by the logic circuit are made compatible, the complex frame processing can be performed and the multi-frame communication having a large communication capacity is possible. Port bridges can be configured.

[0027]

The present invention exhibits the following excellent effects.

(1) Since a multi-port bridge capable of complicated frame processing and having a large communication capacity can be constructed, a high-speed multi-port bridge rich in virtual LAN function can be realized at a small size and a low price.

[Brief description of drawings]

FIG. 1 is a structural diagram of a multi-port bridge showing an embodiment of the present invention.

FIG. 2 is a structural diagram of a conventional multi-port bridge.

FIG. 3 is a structural diagram of a conventional multi-port bridge.

[Explanation of symbols]

100 multi-port bridge 201,202,203 network interface 301,302,303 reception frame judgment unit 400 microcomputer unit 500 unicast frame relay unit

Claims (1)

[Claims] 1. In a multi-port bridge having a plurality of network interfaces and relaying frames between these network interfaces, only a microcomputer unit for relaying broadcast frames and multicast frames and a relay process for unicast frames are provided. A multi-port bridge comprising: a unicast frame relay unit for performing the received frame determination unit for selectively transferring a received frame of each network interface to either the microcomputer unit or the unicast frame relay unit. .