JPH11122303A - Mac bridging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a MAC bridging system in which a medium access control(MAC) broadcast frame is not received in duplicate to a MAC terminal in a MAC protocol LAN. SOLUTION: In the case of receiving a MAC frame from a broad band network 1B, a sender MAC address extract section 1L extracts a sender address and it is fed to an address learning table control section 1J, a transfer table is retrieved by using the sender MAC address as a key and in this case, when the MAC frame is registered in other port than a port of the broad network 1B, the MAC frame is aborted by a MAC frame filtering section 1K.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a MAC bridging device useful for logically forming a MAC bridge network on a wide area frame transfer network.

[0002]

2. Description of the Related Art As represented by a learning bridge, a conventional MAC bridging device discards a MAC frame upon receiving a MAC frame by simply learning the source MAC address and referring to the source MAC address. I never did.

[0003]

When the conventional MAC bridging device is used, when the MAC broadcast frame returns to the MAC bridging device of the transmission source,
There is a problem that the MAC terminal in the MAC protocol LAN accommodated in the transmission source MAC bridging device receives the MAC broadcast frame doubly.

An object of the present invention is to provide a MAC protocol LAN
It is an object of the present invention to provide a MAC bridging device that does not allow a MAC terminal within the same to receive a MAC broadcast frame redundantly.

[0005]

According to the present invention, there is provided a learning bridge type MAC bridging device accommodating a wide area frame transfer network and a MAC protocol LAN, which is provided with a MAC address from a wide area frame transfer network.
When a frame is received, the transfer table is searched using the source MAC address extracted from the MAC frame as a key. If the source MAC address is learned by a specific port other than the port that received the MAC frame, this is searched. It is characterized by having a disposal means.

According to the present invention, a MAC broadcast frame is broadcast in a MAC protocol LAN, and is transmitted through a MAC bridging device.
It is also broadcast outside the MAC protocol LAN. At this time, if the MAC broadcast frame returns to the source MAC bridging device,
The source MAC address of the C frame has been learned by the port on the MAC protocol LAN side. Therefore, source M
If the received MAC frame is discarded when the AC address has been learned by a specific port other than the port that has received the MAC frame, the broadcast is not performed again in the MAC protocol LAN. Therefore, the MAC terminal in the MAC protocol LAN does not receive the MAC broadcast frame redundantly.

[0007]

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

FIG. 1 is a block diagram of the MAC bridging device of the present invention, FIG. 2 is an operation flowchart of an address learning table control unit of the present device, FIG. 3 is a network model showing an application example of the present device, and FIG. FIG. 5 shows a communication procedure using a conventional MAC bridging device, and FIG. 5 shows a communication procedure using a conventional MAC bridging device.

First, the MAC bridging device shown in FIG. 1 will be described. LAN 1A and wide area network 1B
Is connected to the MAC bridging device 1C.
C frame transmission / reception unit 1D, source MAC address extraction unit 1E, destination MAC address extraction unit 1F, MAC frame filtering unit 1G, core frame encapsulation / decapsulation unit 1H, core frame transmission / reception unit 1I, address learning table control unit 1J, It comprises a MAC frame filtering unit 1K and a source MAC address extracting unit 1L.

In such a configuration, a frame transferred from the LAN 1A to the MAC bridging device 1C is input to the MAC frame transmitting / receiving unit 1D. MAC
The frame transmitting / receiving unit 1D receives the M input from the LAN 1A.
The AC frame is transferred to the source MAC address extraction unit 1E.

[0011] The source MAC address extraction unit 1E outputs
The source MAC address is extracted from the MAC frame received from the C frame transmission / reception unit 1D, notified to the address learning table control unit 1J, and the received MAC frame is transferred to the destination MAC address extraction unit 1F. If the source MAC address does not exist on the transfer (learning) table, the address learning table
Register the address.

The destination MAC address extracting unit 1F extracts a destination MAC address from the frame received from the source MAC address extracting unit 1E, notifies the address learning table control unit 1J of the received MAC frame, and converts the received MAC frame into a MAC frame filtering unit. Transfer to 1G.

If the destination MAC address exists in the learning table, the address learning table
It instructs the frame filtering unit 1G to discard the MAC frame, and if the destination MAC address does not exist in the learning table, the MAC frame filtering unit 1G
Instruct transfer of C frame.

The core frame encapsulation / decapsulation unit 1H, which has received the MAC frame from the MAC frame filtering unit 1G, encapsulates the core frame into a core frame and transfers it to the core frame transmission / reception unit 1I. The core frame transmitting / receiving unit 1I transfers the received frame to the wide area network 1B.

On the other hand, the frame transferred from the wide area network 1B to the MAC bridging device 1C is input to the core frame transmitting / receiving unit 1I. Core frame transceiver 1I
Transfers the frame input from the wide area network 1B to the core frame encapsulation / decapsulation unit 1H.

The core frame encapsulation / decapsulation unit 1H decapsulates the MAC frame into a MAC frame,
Transfer to C address extraction unit 1L. The source MAC address extraction unit 1L extracts the source MAC address from the frame received from the core frame encapsulation / decapsulation unit 1H, notifies the address learning table control unit 1J, and filters the received MAC frame by MAC frame filtering. Transfer to unit 1K.

If the source MAC address is present in the learning table, the address learning table
It instructs the C frame filtering unit 1K to discard the MAC frame, and if the source MAC address does not exist in the learning table, instructs the MAC frame filtering unit 1K to transfer the MAC frame.

The MAC frame transmitting / receiving section 1D receiving the frame transfers the MAC frame to the LAN 1A.

Next, the operation of the address learning table control unit will be described with reference to the flowchart of FIG.

FIG. 2 is a flow chart showing LA in FIG.
A step 2A of obtaining the source MAC address from the source address extracting unit 1F, which is different between when bridging from the N side to the wide area network side and when bridging from the wide area network side to the LAN side in FIG. Step 2B of analyzing whether or not the source MAC address exists in the learning table; Step 2 of obtaining the destination MAC address from the destination MAC address extracting unit 1F
C, a step 2D of analyzing whether or not the destination MAC address exists in the learning table; a step 2E of instructing the MAC frame filtering unit 1G to discard the MAC frame; a step 2F of writing the address to the learning table 2F; a MAC frame filtering unit 1G 2G instructing the transfer of the MAC frame to the client, the step 2H of obtaining the source MAC address from the source MAC address extracting unit 1L, the source MA
Step 21 for analyzing whether or not the C address exists in the learning table;
It comprises a step 2J for instructing discard of the C frame, and a step 2K for instructing the MAC frame filtering unit 1K to transfer the MAC frame.

First, the operation of the address learning table control unit at the time of bridging from the LAN side to the wide area network side will be described.

The address learning table controller 1J obtains the source MAC address from the source MAC address extractor 1E (2A). If the source MAC address does not exist on the transfer table (2B), the address is written to the learning table (2F). If the source MAC address exists in the forwarding table (2B), the destination MAC
The destination MAC address is obtained from the address extraction unit 1F (2C).

If the destination MAC address does not exist in the learning table after the above operation is completed (2D), the MAC
It instructs the frame filtering unit 1G to transfer the MAC frame (2F). If the destination MAC address exists in the learning table, the MAC frame filtering unit 1G
To discard the MAC frame (2E).

Next, the operation of the address learning table control unit when bridging from the wide area network to the LAN will be described.

The address learning table controller 1J obtains the source MAC address from the source MAC address extractor 1L (2H). If the source MAC address does not exist in the learning table (2I), the MAC frame filtering unit 1K is instructed to transfer the MAC frame (2).
K). If the source MAC address exists in the learning table (2 #), the MAC frame filtering unit 1K is instructed to discard the MAC frame (2J).

Next, the operation of the network when this apparatus is used will be described.
This will be described using the network model of FIG.

The MAC bridge network 3D shown in FIG. 3 is a core network (CLS conforming to ITU-TI.364).
F network) 3A. M
The communication devices on the AC bridge network 3D include the MAC bridging devices 3E and 3F, the MAC bridging server 3
G and MAC terminals 3H, 3I, 3J.

The function of each device will be described. MAC terminal: a terminal that enables mutual communication by transmitting and receiving a MAC frame MAC bridging device: a proposed MAC bridging device MAC bridging server: a server that resolves the destination of a MAC frame In such a configuration, a MAC bridge network It is assumed that addresses are allocated to communication devices on 3D as follows. MAC terminal 3H: MAC. 1 MAC terminal 3I: MAC. 2 MAC terminal 3J: MAC. 3. Further, it is assumed that addresses are allocated to the communication devices on the core network 3A as follows. MAC bridging server 3G: CORE. 2.1 MAC bridging device 3E: CORE. 1.1 MAC bridging device 3F: CORE. 1.2 Here, the connection relation of the devices will be described. The MAC bridging server 3G, MA
C bridging devices 3E and 3F are connected. Further, the MAC terminal 3E is located ahead of the MAC bridging device 3E.
H and 3I are connected, and a MAC terminal 3J is connected beyond the MAC bridging device 3F.

The proposed MA on this MAC bridge network 3D
A communication procedure using the C bridging device will be described with reference to a communication procedure diagram of FIG.

The communication procedure shown in FIG. 4A includes the transmission of the MAC frame of the MAC terminal 3H (4A) and the transmission of the MAC frame of the MAC terminal 3I.
Frame reception (4B), MAC frame transfer of MAC bridging device 3E (4C), broadcast transfer of MAC bridging server 3G (4D), MAC bridging device 3
F MAC frame transfer (4E), MAC frame discarding of MAC bridging device 3E (4F), MAC terminal 3
Discard J MAC frame (4G), M of MAC terminal 3H
AC frame reception (4H), MAC frame transmission of AC terminal 3I (4I), M of MAC bridging device 3E
AC frame discarding (4J), MAC frame transmission of MAC terminal 3J (4K), M of MAC bridging device 3F
AC frame transfer (4L), broadcast transfer of MAC bridging server 3G (4M), MAC bridging device 3F
Discard MAC frame (4N), transfer MAC frame of MAC bridging device 3E (4O), MAC terminal 3I
MAC frame reception (4P), MAC of MAC terminal 3H
C frame discard (4Q).

FIG. 4B shows address information (address table 4R) in the MAC bridging device 3E, and FIG. 4C shows address information (address table 4S) in the MAC bridging device 3F.

Here, the MAC terminal 3H and the MAC terminal 3I
When the MAC terminal 3H communicates, the MAC terminal 3H transmits the MAC frame to the MAC terminal 3I and the MAC bridging device 3E (4A).

The MAC terminal 3I receives the MAC frame (4B). Upon receiving the MAC frame, the MAC bridging device 3E transmits the source MAC address MAC. 1 is registered on the transfer table 4R, and the MAC frame is transferred to the MAC bridging server 3G (4C).
MAC bridging server 3 that has received the MAC frame
G is a source MAC address MAC. 1 and the source core address CORE. 1.1 is registered on the transfer table, and the MAC frame is broadcast to the MAC bridging devices 3E and 3F (4D).

The MAC bridging device 3F that has received the MAC frame transfers the MAC frame to the MAC terminal 3J (4E). The MAC terminal 3J that has received the MAC frame discards the MAC frame (4G). The MAC bridging device 3E discards the MAC frame (4
F).

After the above operation is performed, the MAC terminal 3I
When the terminal communicates with the MAC terminal 3H, the MAC terminal 3I
Transmits the MAC frame to the MAC bridging device 3E and the MAC terminal 3H (4I).

The MAC terminal 3H receives the MAC frame (4H). Upon receiving the MAC frame, the MAC bridging device 3E transmits the source MAC address MAC. 2 is registered in the transfer table, and the AC frame is discarded (4J).

After the above operation is performed, the MAC terminal 3J
When the terminal communicates with the MAC terminal 3I, the MAC terminal 3J
Transmits the MAC frame to the MAC bridging server device 3
Transfer to F (4K).

Upon receiving the MAC frame, the MAC bridging device 3F transmits the source MAC address MAC. 3 is registered on the transfer table 4S, and the MAC frame is transferred to the MAC bridging server 3G (4L).
MAC bridging server 3 that has received the MAC frame
G is a source MAC address MAC. 3 and the source core address CORE. 1.2 is registered on the transfer table, and the MAC frame is broadcast to the MAC bridging devices 3E and 3F (4M).

The MAC bridging device 3F that has received the MAC frame discards the MAC frame (4N).
The MAC bridging device 3E converts the MAC frame into MA
Transfer to C terminals 3I and 3H (4O). At this time, MAC
The terminal 3H discards the MAC frame (4Q), and the MAC terminal 3I receives the MAC frame (4P).

Next, on the MAC bridge network 3D, the conventional M
A communication procedure using the AC bridging device will be described with reference to FIG.

The communication procedure shown in FIG.
C frame transmission (5A), MAC frame reception of MAC terminal 3I (5B), MA of MAC bridging device 3E
C frame transfer (5C), MAC bridging server 3
G broadcast transmission (5D), MAC frame transfer of MAC bridging device 3F (5E), MAC frame transfer of MAC bridging device 3E (5F), MAC frame discard of MAC terminal 3J (5G), MAC terminal 3I MAC
Frame reception (5H), MAC frame discard of MAC terminal 3H (5I), MAC frame transmission of MAC terminal 3I (5J), MAC frame reception of MAC terminal 3H (5I)
K), MAC frame discard of the MAC bridging device 3E (5L), MAC frame transmission of the MAC terminal 3J (5
M), MAC frame transfer of MAC bridging device 3F (5N), broadcast transfer of MAC bridging server 3G (5O), MAC frame transfer of MAC bridging device 3F (5P), MAC of MAC bridging device 3E
Frame transfer (5Q), MAC frame discard of MAC terminal 3J (5R), MAC frame reception of MAC terminal 3I (5S), MAC frame discard of MAC terminal 3H (5R)
T).

Here, the MAC terminal 3H and the MAC terminal 3I
When the MAC terminal 3H communicates with the MAC terminal 3H, the MAC terminal 3H transmits the MAC frame to the MAC terminal 3I and the MAC bridging device 3E (5A).

The MAC terminal 3I receives the MAC frame (5B). Upon receiving the MAC frame, the MAC bridging device 3E stores the source MAC address MAC. 1 and transfer the MAC frame to the MAC bridging server 3G (5C). M
MAC bridging server 3G that has received the AC frame
Is the source MAC address MAC. 1
And the source core address CORE. 1.1 and register the MAC in the MAC bridging devices 3E and 3F.
Broadcast the frame (5D).

The MAC bridging device 3F that has received the MAC frame transfers the MAC frame to the MAC terminal 3J (5E). The MAC bridging device 3E that has received the MAC frame transfers the MAC frame to the MAC terminals 3I and 3H (5F). At this time, the MAC terminal 3H,
3J discards the MAC frame (5I) (5G),
C terminal 3I receives the MAC frame (5H).

When the MAC terminal 3I and the MAC terminal 3H communicate after performing the above operation, the MAC terminal 3I
The MAC frame is transmitted to the MAC bridging device 3E and the MA
It transmits to C terminal 3H (5J).

The MAC terminal 3H receives the MAC frame (5K). Upon receiving the MAC frame, the MAC bridging server 3E stores the source MA in the forwarding table.
C address MAC. 2 and discard the MAC frame (5L).

When the MAC terminal 3J and the MAC terminal 3I communicate after performing the above operation, the MAC terminal 3J
The MAC frame is transferred to the MAC bridging server device 3F (5M).

Upon receiving the MAC frame, the MAC bridging device 3F transmits the source MAC address MAC. 3 in the forwarding table, and the MAC frame
The data is transferred to the AC bridging server 3G (5N). MA
C bridging server 3G stores the source MAC address MAC. 3 and source core address COR
E. FIG. Register 1.2 and broadcast the MAC frame to the MAC bridging devices 3E and 3F (50).

[0049] Upon receiving the MAC frame, the MAC bridging device 3F transfers the MAC frame to the MAC terminal 5J (5P). The MAC bridging device 3E that has received the MAC frame transfers the MAC frame to the MAC terminals 3H and 3I (5Q). At this time, the MAC terminal 3J,
3H discards the MAC frame (5R) (5S), MA
The C terminal 3I receives the MAC frame (5T).

As described above, when the conventional MAC bridging device is used, when the broadcast is used, the frame is double-broadcast in the transmission source Ethernet, which means that the traffic in the network increases. Which is not preferred. However, by using the device of the present invention,
Even if broadcast is used, filtering based on registered addresses can be performed, and unnecessary traffic can be suppressed. Therefore, it can be said that the device of the present invention is more effective than the conventional device.

[0051]

As described above, according to the present invention,
Even when the MAC frame broadcast-transmitted from the MAC bridging device returns to the original MAC bridging device, the MAC terminal in the MAC protocol LAN does not receive the MAC broadcast frame redundantly. Therefore, it is possible to easily realize a wide area broadcast function between LANs required for connection between LANs, and to reduce the cost of providing a MAC bridging service in a wide area.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a MAC bridging device of the present invention.

FIG. 2 is an operation flowchart of an address learning table control unit in FIG. 1;

FIG. 3 is a diagram showing a network model using the present apparatus.

FIG. 4 is a diagram showing a communication procedure using the present apparatus and an example of setting an address table.

FIG. 5 is a diagram showing a communication procedure using a conventional MAC bridging device.

[Explanation of symbols]

1A: LAN, 1B: Wide area network, 1C: MAC bridging device, 1D: MAC frame transmitting / receiving unit, 1E, 1L:
Source MAC address extraction unit, 1F: Destination MAC address extraction unit, 1G, 1K: MAC frame filtering unit, 1H: Core frame encapsulation / decapsulation unit,
1I: core frame transmitting / receiving unit, 1J: address learning table control unit, 3A: core network, 3B, 3C: Ethernet, 3D: MAC bridge network, 3E, 3F: M
AC bridging device, 3G: MAC bridging server, 3H, 3I, 3J: MAC terminal.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Hara 3-19-2 Nishi Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation

Claims (2)

[Claims] 1. A learning bridge type MAC bridging device accommodating a wide area frame transfer network and a MAC protocol LAN, wherein when a MAC frame is received from the wide area frame transfer network side, a source MAC address extracted from the MAC frame is extracted. The transfer table is searched as a key, and the source MA
A MAC bridging device characterized by comprising means for discarding a C address if it has been learned by a specific port other than the port that received the MAC frame. 2. The MAC bridging device according to claim 1, wherein the specific port is a port for transmitting and receiving a MAC frame to and from a MAC protocol LAN.