JPH11112547A - Switching hub - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely realize communication to which real time ability is requested by preferentially transferring an Ethernet frame to which a specified virtual LAN number is added compared to the other frames. SOLUTION: It is assumed that a switching hub 10 simultaneously receives the Ethernet frames 11 and 12 addressed to a terminal 15 from a terminal 14 and a terminal 16. The switching hub 10 recognizes that the terminal 14 and the terminal 15 belong to virtual LAN number =1 and the terminal 15 and the terminal 16 to a virtual LAN number = 2. At that time, the switching hub 10 transfers the Ethernet frame 11 to which the virtual LAN number = 1 with high priority is added to the terminal 15 and transfers the Ethernet frame 12 to the terminal 15. When the number of the received Ethernet frames exceeds the maximum processing ability of the switching hub, the switching hub 10 transfers the Ethernet frame 11 to the terminal 15 and cancels the Ethernet frame 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a switching hub, and more particularly, to a switching hub having a priority when transferring an Ethernet frame on a LAN.

[0002]

2. Description of the Related Art A switching hub is an important device indispensable for data transfer on a LAN.

FIG. 3 is a schematic configuration diagram of a communication system using a switching hub. Terminals 41 to 44 are connected to the switching hub 20. Switching hub 2
0 indicates data transfer from the terminal 41 to the terminal 42 and the terminal 44
From the terminal 43 to the terminal 43 at the same time.

FIG. 4 is a schematic configuration diagram of a communication system using a switching hub with a virtual LAN function. Virtual LA
Terminals 45 to 48 are connected to the switching hub 21 with the N function. The switching hub 21 limits data transfer between terminals belonging to the same virtual LAN number, and prevents unnecessary frames from flowing on the network. FIG.
, The terminals 45 to 47 belong to the virtual LAN number = 1, and the terminal 48 belongs to the virtual LAN number = 2. The switching hub 21 transfers data from the terminal 45 to the terminal 46, but does not transfer data from the terminal 48 to the terminal 47. Here, the data transfer is specifically an Ethernet frame transfer, and not performing the transfer means discarding the Ethernet frame.

FIG. 5 is a configuration diagram of an Ethernet frame. The virtual LAN number to which the source terminal belongs is added to the Ethernet frame 30 and transmitted to the switching hub 21. The virtual LAN number to which the destination terminal belongs is recognized by referring to a table in the switching hub 21 that associates the address of each terminal with the virtual LAN number.

FIG. 6 shows a switching hub 2 in a communication system using a switching hub with a virtual LAN function.
FIG. 1 is an explanatory diagram in the case where 1 relays an Ethernet frame. A terminal 49 having an address = A, a terminal 50 having an address = B, and a terminal 51 having an address = C are connected to the switching hub 21, and the terminal 49 has a virtual LAN number = 1, the terminal 51 has a virtual LAN number = 2, The terminal 50 belongs to both the virtual LAN numbers = 1 and 2. Further, the table 31 inside the switching hub 21 includes an address = A and a virtual LAN number = 1, an address = B and a virtual LAN number = 1,
Address = B and virtual LAN number = 2, and address = C and virtual LAN number = 2 are registered in association with each other.

When the switching hub 21 receives the Ethernet frame 30 addressed to the terminal 50 from the terminal 49, the switching hub 21 recognizes that the virtual LAN number to which the source terminal 49 belongs is 1 from the Ethernet frame 30,
And the virtual L to which the terminal 50 with the destination address = B belongs
It recognizes that the AN number is 1. In this case, the switching hub 21 transmits the Ethernet frame 30 to the terminal 50 because the virtual LAN numbers to which the source terminal 49 and the destination terminal 50 belong are the same.

FIG. 7 shows a switching hub 2 in a communication system using a switching hub with a virtual LAN function.
FIG. 1 is an explanatory diagram in a case where an Ethernet frame is not relayed. When the switching hub 21 receives the Ethernet frame 30 addressed to the terminal 51 from the terminal 49, the virtual LAN to which the source terminal 49 belongs from the Ethernet frame 30.
It recognizes that the number is 1 and also recognizes that the virtual LAN number to which the terminal 51 having the destination address = C belongs is 2 with reference to the table 31. In this case, the source terminal 4
The switching hub 21 discards the Ethernet frame 30 because the virtual LAN numbers to which the destination terminal 50 and the destination terminal 9 belong are different.

[0009]

The conventional switching hub with a virtual LAN function limits the transfer of Ethernet frames between terminals belonging to the same virtual LAN number, and prevents unnecessary frames from flowing on the network. Since the priority of the Ethernet frame transfer cannot be controlled, there is a problem that data having high real-time properties such as video and audio are discarded. For example, if the number of received Ethernet frames is close to or exceeds the maximum processing capacity limit of the switching hub, the switching hub gives priority to data with high real-time properties, that is, high urgency, in the received Ethernet frames. Must be transferred. Otherwise, the switching hub cannot transfer data, and loses data with high real-time properties.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a switching hub which can solve the above-mentioned drawbacks of the prior art and can transfer an urgent Ethernet frame with priority.

[0011]

In order to achieve the above object, according to the present invention, a switching hub for transferring an Ethernet frame on a LAN (Local Area Network) reads a virtual LAN number added to the Ethernet frame, An Ethernet frame to which a specific virtual LAN number is added is transferred with higher priority than other frames.

If the number of received Ethernet frames exceeds the maximum processing capacity of the switching hub, a priority is set to the virtual LAN number added to the Ethernet frame, and a virtual LAN with a higher priority is set. An Ethernet frame having a number may be preferentially transferred without being discarded.

The transfer of the Ethernet frame may be performed only to terminals having the same virtual LAN number.

[0014]

FIG. 1 is a configuration diagram of a communication system using a switching hub with a virtual LAN function according to the present invention. The switching hub 10 has terminals 14, 15, 16
Is connected. The switching hub 10 is a virtual LA
The priority of the group of virtual LAN number = 1 is set higher than the group of N number = 2. A terminal 14 having an address = A, a terminal 15 having an address = B, and a terminal 16 having an address = C are connected to the switching hub 10, and the terminal 14 has a virtual LAN number = 1 and the terminal 16 has a virtual LAN number.
The terminal 15 belongs to both the virtual LAN numbers = 1 and 2 for the number = 2.

Further, a table 13 inside the switching hub 10 has an address = A and virtual LAN number = 1, an address = B and virtual LAN number = 1, an address = B and virtual LAN number = 2, and an address = C and virtual LAN number = 2. LAN number = 2 is registered in association with each other.

Referring to FIG. 1, a switching hub 10 includes an Ethernet frame 11 from a terminal 14 to a terminal 15;
When the switching hub 10 receives the Ethernet frame 12 addressed to the terminal 15 from the terminal 16 at the same time, the switching hub 10
4 and terminal 15 both belong to virtual LAN number = 1, and terminal 1
5 and the terminal 16 recognize that both belong to the virtual LAN number = 2. At this time, the switching hub 10 transfers the Ethernet frame 11 to which the high priority virtual LAN number = 1 is added to the terminal 15 first, and then transfers the Ethernet frame 12 to the terminal 15.

FIG. 2 is an explanatory diagram of frame processing when an Ethernet frame is received near the limit of the maximum processing capacity of the switching hub 10 or exceeding the processing capacity in the same network configuration as in FIG.
When the switching hub 10 simultaneously receives the Ethernet frame 11 addressed to the terminal 15 from the terminal 14 and the Ethernet frame 12 addressed to the terminal 15 from the terminal 16, the switching hub 10 transmits the Ethernet frame to which the high priority virtual LAN number = 1 is added. The frame 11 is transferred to the terminal 15 and the Ethernet frame 12 to which the low priority virtual LAN number = 2 is added is discarded. In this way, data with high urgency is not lost.

[0018]

According to the switching hub of the present invention, the priority of transfer is recognized based on the virtual LAN number, and the Ethernet frame to which the virtual LAN number having the higher priority is added can be transferred with priority over other Ethernet frames. Therefore, communication that requires real-time properties such as video and audio can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a communication system using an embodiment of a switching hub of the present invention.

FIG. 2 is an explanatory diagram of frame processing when the switching hub is near or beyond the processing capacity limit in FIG.

FIG. 3 is a schematic configuration diagram of a communication system using a conventional switching hub.

FIG. 4 is a schematic configuration diagram of a communication system using a conventional switching hub with a virtual LAN function.

FIG. 5 is a configuration diagram of an Ethernet frame used in the communication system of FIG. 4;

FIG. 6 is an explanatory diagram of frame transfer in a conventional communication system using a switching hub with a virtual LAN function.

FIG. 7 is an explanatory diagram of frame discarding in a conventional communication system using a switching hub with a virtual LAN function.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Switching hub 11, 12 Ethernet frame 13 Table 14, 15, 16 terminal 20 Switching hub 21 Switching hub with virtual LAN function 30 Ethernet frame 31 Table 41-51 Terminal

Claims (3)

[Claims] 1. A switching hub for transferring an Ethernet frame on a LAN (Local Area Network),
A switching hub for reading a virtual LAN number added to an Ethernet frame and transferring the Ethernet frame added with a specific virtual LAN number with priority over other frames. 2. When the number of received Ethernet frames exceeds the maximum processing capacity of a switching hub, a priority is set to a virtual LAN number added to the Ethernet frame, and a high priority is set. 2. The switching hub according to claim 1, wherein the Ethernet frame having the virtual LAN number is preferentially transferred without being discarded. 3. The switching hub according to claim 1, wherein the transfer of the Ethernet frame is performed only to terminals having the same virtual LAN number.