JPH1174923A - Switching hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide switching hubs which can recognize that the setting of tag ports is erroneous. SOLUTION: In the switching hub 101 which has plural ports for repeating a frame and can set more than one ports to be the tag ports transmitting/ receiving the tag frame to which virtual LAN information is added, the tag existence notice frame showing the existence of the tag port designating a bridge and a multicast address for bridge that only the switching hub can receive for an address is transmitted from the tag port 145. When the tag port existence notice frame is received from the port 151, the other switching hub 102 does not repeat the frame.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub capable of setting a tag port for transmitting and receiving a tag frame to which virtual LAN information is added, and more particularly to a switching hub capable of recognizing that a tag port setting is erroneous. It is.

[0002]

2. Description of the Related Art In Ethernet defined by IEEE (American Association of Electrical and Electronic Engineers) 802.3, one local area network (LAN) is physically provided.
Is divided into multiple logical networks (virtual LAN)
Is used. Referring to FIG. 1 of the present invention, the physical LAN configured by using the switching hubs 101 and 102 includes virtual LANs 131 and 13.
2 are formed.

[0003] In order to exchange virtual LAN information between switching hubs, a method of adding and transmitting virtual LAN information called a tag to a frame and transmitting / receiving the frame is being discussed by the IEEE 802.1q committee.

In FIG. 1, ports 141, 142, 1
The ports 54 and 155 belong to the virtual LAN 131, and the ports 143, 144, 152 and 153 belong to the virtual LAN 132. The ports 145 and 151 are connected to the virtual LA
It belongs to two virtual LANs, N131 and virtual LAN132. When one port belongs to a plurality of virtual LANs, that port is called a tag port. The tag port transmits a special frame (tag frame) having a virtual LAN identification field corresponding to a tag in a normal frame. Ports 145 and 151 in FIG. 1 are tag ports.

[0005] The tag frame has a format shown in FIG. That is, the tag frame is
It consists of a destination address field DA, a source address field SA, a virtual LAN identification field TAG, a type field TYPE, a data field DATA, and a frame inspection sequence field FCS. Of these, the virtual LAN identification field TAG starts with a type field TYPE, Flag field FLAG, priority field P, virtual LANID field V
ID.

The tag port adds a tag when transmitting a frame, and upon receiving a tag frame, determines the virtual LAN to which the frame belongs by checking the contents of the tag, Remove the tag and relay the frame.

An example of transmitting a frame from communication terminal 124 to communication terminal 126 will be described with reference to FIG. First, the communication terminal 124 sends a normal Ethernet frame to port 1
Send to 44. The port 144 determines that the communication terminal 126 is located beyond the port 145 to relay the received frame, and transfers the frame to the port 145. Since the port 145 is a tag port, the received frame is tagged and transmitted. The transmitted tag frame reaches the port 151 through the transmission path 111. Port 1
51 receives the tag frame, removes the tag, determines the destination of the frame, and transfers the frame to the port 153. When the port 153 transmits a frame, the communication terminal 126 receives the frame.

[0008]

The setting of the tag ports of the switching hubs 101 and 102 shown in FIG. 1 is all performed by the user. For example, if the port 151 forgets to set the port 151 as a tag port, when the port 151 receives the tag frame addressed to the communication terminal 126 from the port 145, the port 151 performs only the destination determination and transfers the frame without removing the tag. 153. Even if the communication terminal 126 receives this frame, the tag cannot be analyzed and the frame is discarded. Therefore, the port 145
The frames transmitted from are unnecessary traffic.

In the prior art, there is no means for recognizing that the setting of the tag port is erroneous. Therefore, if the setting of the tag port is erroneous as described above, unnecessary traffic is generated.

An object of the present invention is to solve the above-mentioned problems and to provide a switching hub that can recognize that a tag port setting is incorrect.

[0011]

In order to achieve the above object, the present invention has a plurality of ports for relaying a frame, and transmits and receives a tag frame to which virtual LAN information is added to at least one of the ports. In a switching hub that can be set as a tag port, a tag port presence notification frame indicating the presence of a tag port that has specified a bridge multicast address that can be received only by the bridge or switching hub as the destination is transmitted from the tag port, and from another switching hub When the tag port presence notification frame is received, this frame is not relayed.

When the tag port does not receive a tag port presence notification frame from another switching hub even after a certain period of time, it may recognize that the setting of the tag port is incorrect.

[0013] When recognizing that the setting of the tag port is incorrect, a network error notification frame for notifying that the setting of the tag port is incorrect may be transmitted to a network management apparatus to which an address is set in advance. .

[0014]

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

As shown in FIG. 1, virtual LANs 131 and 132 are formed on a physical LAN configured using the switching hubs 101 and 102 according to the present invention. The switching hub 101 has ports 141 to 14
5 and ports 141 to 144 have communication terminals 121 to 121.
124 are connected. The switching hub 102
It has ports 151 to 155, and communication terminals 125 to 128 are connected to the ports 152 to 155 (1
28 is a network management device). Port 145, 151
Are interconnected.

In FIG. 1, ports 141, 142, 1
The ports 54 and 155 belong to the virtual LAN 131, and the ports 143, 144, 152 and 153 belong to the virtual LAN 132. The ports 145 and 151 are connected to the virtual LA
It is a tag port belonging to two virtual LANs, N131 and virtual LAN132.

These switching hubs 101 and 102
Means that at least one tag port is set on the network as shown in FIG. 3 from the port set as the tag port.
One transmits a frame indicating that it is present (hereinafter, referred to as a tag port presence notification frame) at regular time intervals. The tag port presence notification frame includes a destination address field DA, a source address field S
A, type field TYPE, data field DA
It comprises a TA and a frame inspection sequence field FCS, and a value indicating that this frame is a tag port presence notification frame is set in the type field TYPE. A bridge multicast address is specified as the destination address in the destination address field DA.
The bridge multicast address is an address that is received only by a bridge or a switching hub and not received by a communication terminal such as a personal computer. This allows transmission to all switching hubs on the network and prevents the tag port presence notification frame from imposing an extra load on communication terminals such as personal computers.

The switching hubs 101 and 102
When a tag port presence notification frame is received from another switching hub, the frame is not relayed by not performing a transfer process of transferring the frame to a port other than the reception port. Therefore, the tag port presence notification frame is not relayed to another switching hub via one or more switching hubs, and when the tag port receives the tag port presence notification frame, the paired tag ports are the same. It can recognize that it is on the network.

In the network of FIG. 1, when a user newly sets a tag port in the switching hubs 101 and 102, the switching hub 10
1, 102, the reception waiting time of the tag port presence notification frame for the tag port is set. When the switching hubs 101 and 102 do not receive the tag port presence notification frame even after the reception waiting time has elapsed at the newly set tag port, the tag port that is a pair of the tag port does not exist on this network. It is determined that the tag port setting is incorrect, and a frame (network error notification frame) for notifying the determination is transmitted to the network management device to which the address is set in advance. The user can recognize through the network management device that the setting of the tag port is incorrect.

If the newly set tag port is the first tag port on the network, no tag port presence notification frame is received from another tag port. Set the frame reception waiting time to indefinite. By doing so, it is possible to prevent the switching hub having the first tag port from transmitting a network error notification frame while setting another tag port.

An operation example of the switching hub in the network of FIG. 1 will be described.

First, when the user sets a tag port for the port 145 of the switching hub 101, at this time, a tag port that is a pair of the port 145 has not been set on the network yet, and the switching hub 101 has a tag port. Since the notification frame is not received, the reception waiting time of the tag port presence notification frame for the port 145 is set indefinitely, and the network error notification frame is received even if the port 145 does not receive the tag port presence notification frame. Not to be sent.

Thereafter, the switching hub 101 transmits the tag port presence notification frame shown in FIG. 3 from the port 145 at a fixed time interval (here, 30 seconds). That is, a bridge multicast address is described in the destination address field DA of this frame, and a value indicating that this frame is a tag port presence notification frame is set in the type field TYPE.

Here, it is assumed that the user newly sets the port 151 of the switching hub 102 as a tag port and sets the reception waiting time of the tag port presence notification frame to 60 seconds. As a result, the tag port paired with the port 145 of the switching hub 101 is set, and the reception wait time of the tag port presence notification frame at the port 145 is changed from indefinite to 60 seconds.

Since the switching hub 101 transmits a tag port presence notification frame to the switching hub 102 from the port 145 at intervals of 30 seconds, the switching hub 102 transmits the tag 151 to the port 151 during the reception waiting time of 60 seconds.
Can receive the tag port presence notification frame. Thus, the switching hub 102 can recognize that at least one tag port for receiving the transmitted tag frame exists on the same network.

If the port 151 is set as a tag port in a state where the port 145 is not set as a tag port, the port 151 receives the tag port existence notification frame even after the reception waiting time of 60 seconds has elapsed. Therefore, the switching hub 102 transmits a network error notification frame to the network management device 128.
Thereby, the user can recognize in the network management device that the setting of the tag port is incorrect.

As described above, according to the present invention, it is possible to detect the presence of an unpaired illegal tag port on a network. As a result, by setting the tag port correctly by the user, unnecessary traffic can be prevented from flowing on the network. In addition, since the tag port presence notification frame uses the bridge multicast address as the destination address, it can be received by all switching hubs on the network and does not impose an extra load on communication terminals such as personal computers.

[0028]

The present invention exhibits the following excellent effects.

(1) When there is no paired tag port on the same network, it is notified that the setting of the tag port is erroneous, so that unnecessary traffic on the network can be reduced.

(2) Since the bridge multicast address is used in the tag port presence notification frame, no extra load is applied to the communication terminal such as a personal computer.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a network using a switching hub according to an embodiment of the present invention.

FIG. 2 is a format diagram of a tag frame.

FIG. 3 is a format diagram of a tag port presence notification frame.

[Explanation of symbols]

 101,102 switching hub 121-128 communication terminal 131-132 virtual LAN 141-145,151-155 port

Claims (3)

[Claims] 1. A virtual LAN having a plurality of ports for relaying a frame, of which at least one port is a virtual LAN.
In a switching hub that can be set as a tag port that transmits and receives tag frames with added information, a tag port presence notification frame that indicates the presence of a tag port that specifies a bridge or a bridge multicast address that can only be received by the switching hub is sent to the tag port. The switching hub does not relay the frame when the tag port presence notification frame is transmitted from another switching hub. 2. The apparatus according to claim 1, wherein when the tag port does not receive a tag port presence notification frame from another switching hub within a predetermined time, it recognizes that the setting of the tag port is erroneous. Switching hub. 3. Recognizing that the setting of the tag port is incorrect, transmitting a network error notification frame notifying that the setting of the tag port is incorrect to a network management device to which an address is set in advance. The switching hub according to claim 1 or 2, wherein