JPH09149069A - Switching hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To omit the transfer of frames to a port not required even when an object port is unclear and frames are transferred to all ports. SOLUTION: Number of destination addresses registered in a path table of the switching hub 101 is designated in advance to ports 1-4. When a destination address of a frame sent from a station is not registered in any path table of ports, it is discriminated that no destination station is in existence to ports to which a designated number of addresses is already registered, and the frame is transferred to other ports, then occurrence of undesired track to a transmission line to a station not needing the reception of the frame is prevented and the operating efficiency of the network is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub that switches a transmission line between ports according to a destination of a frame to perform a transfer process, and is particularly necessary when a frame is transferred to all ports because the corresponding port is unknown. The present invention relates to a switching hub in which transfer to a port without a port can be omitted.

[0002]

2. Description of the Related Art As a network concentrator, there is known a switching hub which connects a plurality of terminals and switches a transmission path according to a destination of a frame transmitted by these terminals to perform a transfer process.

An embodiment of the present invention will be described with reference to FIG. 1. In the network system shown in FIG. 1, each terminal communicates at a transmission speed of 10 Mbps Ethernet. It is a relay device (concentrator) that establishes a plurality of transmission lines connected one-to-one and allows terminals to communicate with each other on each transmission line.

Further, the switching hub 101 has a route table for registering the source address of the received frame for each port, and by connecting the source address of the received frame to the route table, the switching hub 101 is connected to the port. It has the function of learning which stations are in use.

When the switching hub 101 receives the frame transmitted from the terminal, the switching hub 101 holds the destination address of the frame, and refers to the above-mentioned routing table to send the frame only to the port where the address is registered. Forward.

If the destination address of the received frame is not registered in the route table of any port, the switching hub 101 cannot determine the port to which the terminal having the destination address is connected, so that the frame must be the destination. Forward the frame to all ports to reach the terminal.

[0007]

As described above, in the conventional switching hub, when the destination address of the received frame is not registered in the route table of any port, the port to which the destination station is connected is selected. It can't know and forwards frames to all ports. As a result, unnecessary traffic is generated on the transmission path to the terminal that does not need to receive the frame, and communication of the terminal is disturbed.

[0008] Therefore, an object of the present invention is to solve the above problems and to provide a switching hub capable of omitting forwarding to unnecessary ports even when the relevant port is unknown and frames are forwarded to all ports. .

[0009]

In order to achieve the above object, the present invention has a plurality of ports, has a routing table for registering a source address of a frame received for each port, and receives from a certain port. In a switching hub that can transfer a frame to the corresponding port by referring to the routing table with the destination address of the frame, specify the number of addresses that can be registered in the routing table for each port in advance, and the destination of the received frame When the address is not registered in the route table of any port, the frame is transferred only to the port where the number of addresses specified above has not been registered yet.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The gist of the present invention is to specify in advance the number of destination addresses to be registered in the routing table of a switching hub for each port, and the destination address of a frame transmitted from a certain station If it is not registered in the table, it is judged that the destination station does not exist in the port where the specified number of addresses have already been registered, and the frame is received only by transferring the frame to other ports. It is possible to prevent unnecessary traffic from being generated in a transmission path to a station that does not need to operate, and to improve network use efficiency.

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

As shown in FIG. 1, the switching hub 101 has a plurality of ports 1 to 4 and has a routing table (FIG. 2) for registering the source address of the frame received for each port. The frame received from the frame can be transferred to the corresponding port by referring to the routing table with the destination address of the frame. For each port 1 to 4,
The terminals 111, 112, 113 or the repeater 121 are connected. Terminals 114 and 115 are connected to the repeater 121, and therefore terminals 114 and 11 are connected to the port 3.
5 is connected.

Further, as shown in FIG. 2, the route table is
It is composed of a destination address storage unit 201 and a designated number storage unit 202. The destination address storage unit 201 registers the source address of the frame received by the port, and the designated number storage unit 202 can be registered in advance in the routing table. The number of addresses is specified. The MAC address is used as the destination address here.

Next, the operation will be described.

First, the number of destination addresses that can be registered in the routing table of the switching hub 101 is designated. Here, only one terminal is connected to each of port 1 and port 2, and the number of registered destination addresses of port 1 and port 2 is designated as 1. Nothing is specified for port 3 and port 4 where the number of terminal connections is not determined.

By learning, the MAC address A1 of the terminal 111 is stored in the destination address storage section of the port 1, and the MAC address B of the terminal 112 is stored in the destination address storage section of the port 2.
1 and M of the terminal 114 in the destination address storage of port 3
It is assumed that the MAC address D1 of the terminal 113 is registered in the AC address C1 and the destination address storage unit of the port 4. A frame has not yet been received from the terminal 115 whose MAC address is C2, and a connection port has not been learned.

In this state, from the comparison between the designated number and the actually registered number, there is no terminal with an address other than A1 in port 1, there is no terminal with an address other than B1 in port 2, There may be a terminal with an address other than C1 on port 3, Q1 on port 4.
It can be determined that there is a possibility that there is a terminal with an address other than.

Here, when the terminal 113 transmits a frame to the terminal 115, the switching hub 101 operates on the port 4
Refers to the routing table with the destination MAC address (C2) of the received frame, and finds that this MAC address (C2) is not registered in the routing table of any port. Therefore, in the conventional case, the frame is transferred to all ports. However, in the present invention, since one designated MAC address has already been registered in each of port 1 and port 2, it can be determined that there is no destination terminal in those ports. On the other hand, no specified number is specified for port 3, and therefore it is possible to register two or more MAC addresses and the currently registered MAC
There is one address. That is, since the specified number of MAC addresses have not been registered yet, there is a possibility that a terminal having an unlearned MAC address (C2) is connected. Port 4 is a receiving port. Therefore, the frame is transferred only to the port 3. As a result, the frame transmitted from the terminal 113 to the terminal 115 reaches the terminal 115 from the port 3.

By thus designating the number of destination addresses to be registered in the routing table in advance, if the destination address of the frame received by the switching hub 101 is not yet registered in the routing table, the specified number of destination addresses is registered. It can be determined that the target terminal does not exist at the port whose address has already been registered.

Further, by not transferring the frame to the port where the target terminal does not exist, unnecessary traffic is not transmitted to the transmission line to which the terminal that does not receive the frame is connected, thereby improving the efficiency of use of the network. You can

For example, in the configuration of FIG. 1, when the frame addressed to the terminal 115 from the terminal 113 is being transferred from the port 4 to the port 3 as described above, the frame addressed to the terminal 111 from the terminal 111 is changed to the port 1 If it is received by the device, it can be immediately forwarded to port 2.

In the above embodiment, the port 3
Although no designation was made for the designated number of, the number of designations such as 2, 3, ... May be designated.

[0023]

The present invention exhibits the following excellent effects.

(1) Even when the frame is transferred to all ports because the corresponding port is unknown, the frame is transferred only to the port where the specified number of addresses are not yet registered, so that the specified number of addresses are The frame is not transferred to the already registered port, so that unnecessary traffic does not occur in the transmission path to the terminal that does not need to receive the frame, and the use efficiency of the network can be improved.

[Brief description of the drawings]

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

FIG. 2 is a configuration diagram of a routing table according to the present invention.

[Explanation of symbols]

 101 switching hub 201 destination address storage unit 202 designated number storage unit

Claims (1)

[Claims] 1. A routing table, comprising a plurality of ports, for registering a source address of a frame received for each port,
In a switching hub that can transfer a frame received from a port to the corresponding port by referring to the routing table with the destination address of the frame, specify the number of addresses that can be registered in the routing table for each port in advance, Switching characterized in that if the destination address of the received frame is not registered in the routing table of any port, the frame is transferred only to the port where the number of addresses specified above has not been registered yet. Hub.