JPH09186715A - Network frame repeater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a network frame repeater transferring data at a high speed even in a broadcast introducing the concept of a VLAN by storing information representing cross reference between an address of a terminal equipment and a port through which data are sent when the terminal equipment acts as a sender of the data. SOLUTION: This network repeater stores a MAC address and information to which VLAN a terminal equipment belongs and generates a MAC-VLAN table (A). The MAC-VLAN table (A) is converted into a VLAN-MAC table (B) to retrieve a MAC address from a VLAN. Further more, in the repeater, a MAC-port table (C) representing the cross reference between a MAC address and a port is generated. The VLAN-MAC table (B) and the MAC-port table (C) are merged into an entry port table (D).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network frame repeater provided in a network system for relaying transmission of network frames.

[0002]

2. Description of the Related Art Conventionally, in a network system,
For example, there is a network frame repeater called a “hub” or the like that relays transmission of a network frame as a chunk of information transmitted and received in the network. FIG. 4 is a circuit block diagram showing a configuration example of a conventional network frame repeater.

The network frame repeater 1 shown here
0 is provided with n port controllers 12_1, ..., 12_n connected to the bus 11, and each port 13_1, ..., 13_n corresponding to each port controller 12_1 ,.
, 14_n, a plurality of terminals A, B, ..., C;
...; E, F, ..., G are connected.

Further, the bus 11 stores a search table 15a indicating the correspondence between the address of each terminal and the port number, and the search table 15a is searched to convert the address of the terminal into the port number. A memory (content address memory; CAM) 15, a sequencer 16 that controls the entire network frame repeater 10, and a packet memory 17 that temporarily stores the transmitted network frame are provided.

The network frame repeater is usually further provided with various devices and the like, but since they are not directly related to the description here, their illustration and description are omitted. Here, LAN14_1
It is assumed that certain information having the format of the network frame is transmitted from the terminal B connected to the terminal B to the terminal E connected to the LAN 14_n.

At this time, in the header of the network frame, a destination address of the information, that is, a destination address indicating the terminal E, and a source of the information, that is, a source address indicating the terminal B are recorded.
The network frame transmitted from the terminal B via the port 13_1 is transmitted to the port controller 12 1 and then via the bus 11 to the packet memory 17
Is accumulated in After that, the sequencer 16 extracts the destination address representing the data transfer destination (terminal E in this example) from the header portion in the network frame stored in the packet memory 17 to obtain the CAM.
Send to 15. The CAM 15 has terminals A, B, ..., C; ...; E, F ,.
G and their respective terminals A, B, ..., C; ...; E, F ,.
A correspondence table 15a with a port number indicating which port 13_1, ..., 13_n G is connected to is stored, and the CAM 15 inputs the destination address and indicates the destination address. Outputs the port number that indicates the connection destination of the terminal.

Based on this port number, the sequencer 16
Recognizes that the current network frame is a network frame to be transmitted from the port 13_n. When the port number is output from the CAM 15 in this manner, subsequently, the network frame is
It is input from the packet memory 17 to the port controller 12_n via the bus 11, is transmitted to the terminal E via the port 13_n, and further via the LAN 14_n.

About the network frame configured as described above, a virtual LAN (VLAN; Vertu)
The concept of "al Local Area Network" is considered. FIG. 5 is a schematic diagram for explaining the concept of VLAN. The network frame relay 10 has ports 0 (port 0) to n (port).
It is assumed that n + 1 ports up to n) are prepared, terminals A and B are connected to port 0, terminals C and E are connected to port 1, and terminal D is connected to port 2 as illustrated.

Here, it is assumed that the terminals A and B belong to the group VLAN1, the terminals B and E belong to the group VLAN2, and the terminals C, D, and E belong to the group VLAN3. At this time, for example, a plurality of methods are conceivable as a method of transmitting data originating from the terminal E.

One of the plurality of transmission methods is shown in FIG.
This is a transmission method called unicast in which only one data transmission destination is specified and transmitted as described above, and as described above, for example, when the destination is the terminal D, the header of the network frame Then, the address of the terminal D is written as the destination address and transmitted.

The second communication method among the plurality of transmission methods is a multicast in which a plurality of terminals, for example, terminals B and D, are designated as transmission destinations from the transmission source terminal E and transmitted. Is a communication method called. Further, when the above-mentioned concept of VLAN is introduced, another transmission method is conceivable. That is, an unspecified terminal belonging to the group of VLANs to which the terminal E that is the source belongs (in the example shown in FIG.
Is a communication method for transmitting data to a terminal B belonging to the terminal B and terminals C and D belonging to the VLAN 3. Here, this is called a broadcast. The present invention is mainly concerned with this broadcast.

[0012]

As described above, the VLAN is used.
Introduce the concept of broadcast (broadcas
t) When the communication method is introduced, the problem is how fast the network frame sent to the network frame repeater is determined, and the port for transmitting the network frame is determined and the network frame is transmitted from the port. Become.

In view of the above circumstances, it is an object of the present invention to provide a network frame repeater capable of quickly determining a port for outputting a network frame, including the broadcast transmission mode.

[0014]

SUMMARY OF THE INVENTION To achieve the above object, a network frame repeater of the present invention is a source of a network frame as a block of information including a source address indicating a source and a destination address indicating a destination. Alternatively, it has a plurality of ports for transmitting and receiving network frames, each of which can be connected to one or more terminals that can be receiving destinations, and a receiving network frame received at any port is received by the receiving network frame. In the network frame relay that transmits from the port to which the destination terminal is connected, the address of the terminal connected to the port is stored and the same address as the destination address or source address included in the received network frame is stored. Stored Correspondence between the address of the terminal of the destination of the network frame and the port to which the terminal of the destination is connected, provided with an associative memory for searching whether The relationship and the information indicating the correspondence between the address of the source terminal of the network frame and the port to which the terminal of the destination of the network frame transmitted from the source terminal address is connected are stored and received. An address conversion circuit that searches the associative memory based on a destination address or a source address included in the network frame, and that specifies a port that transmits the received network frame based on the above information, and the received network frame to the address Is the port specified by the conversion circuit Characterized by comprising a transmission control circuit for transmitting.

The network repeater of the present invention is information indicating the correspondence between the address of the terminal of the destination of the network frame and the port to which the terminal of the destination is connected (this information is the above-mentioned unicast case). Information) that indicates the correspondence between the address of the source terminal of the network and the port to which the terminal receiving the network frame sent from the source terminal address is connected. In the case of broadcasting, since the port information is obtained based on the source address in the network frame indicating the originator during broadcasting, high-speed data transfer is possible even during broadcasting.

Here, in the network repeater of the present invention, the associative memory stores a correspondence table of addresses of terminals connected to the ports and ports to which the terminals are connected. The conversion circuit includes the associative memory, and the associative memory
A memory is provided at an address corresponding to the address where the address of the terminal connected to the above-mentioned port is stored, which stores information indicating the port to which the terminal which is the destination of the network frame transmitted from the terminal is connected. Is preferred. In this case, the memory capacity of the associative memory itself can be reduced.

Further, in the network frame repeater of the present invention, it is preferable that the information designating the port is represented by a bit pattern in which each bit is associated with each port. In this way, when the port instruction information is represented by a bit pattern in which each bit is associated with each port, the bit pattern is instructed to each port as to whether or not to transmit the network frame. It can be used as the control data to be used, and the data transfer can be further speeded up in the case of Marchast.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a diagram showing a correspondence table of an address of a terminal and a port to which a terminal which is a receiver of a network frame when the terminal is a source is connected, in an embodiment of the network frame repeater of the present invention. It is a schematic diagram which shows the process. Here, the VL shown in FIG.
An AN structure is assumed.

First, according to the specifications of the user of this network frame repeater, the MAC address (the address of each terminal described above; the MAC addresses of the terminals A, B, ... Are Ma, Mb ,. And the VLAN to which the terminal belongs is stored, and the MAC-VLAN table shown in (A) is created. This MA
The C-VLAN table is converted into a VLAN-MAC table (B) that searches a MAC address from the VLAN. Further, in this network frame repeater, while the network frame is being communicated, the MA
M representing the correspondence between the MAC address indicating the port to which the terminal having the C address is connected and the port
An AC-port table (C) has been created. This MAC-port table is constantly updated with new table information from the correspondence between the header information of the network frame and the port to which the network frame is transmitted while the network frame relay device relays the network frame. Has been updated.

Here, the VLA created in this way
The N-MAC table (B) and the MAC-port table (C) are merged (mixed) to create an entry port table (Entry-ports table) shown in (D). This entry port table shows that each MAC address is associated with each port, and that a network frame whose source is each MAC address is transmitted to the port of bit '1'. For example, the network frame originating from the terminal E (MAC address Me) shown in FIG.
It indicates that the data should be transmitted to the three ports 1 and 2. However, in this embodiment, the MAC address and the port number are not directly associated with each other, and the HHA (Highest Hit Address) described later is used.
Are associated with each other.

FIG. 2 is a block diagram showing the configuration of an embodiment of the network frame repeater of the present invention, and FIG.
It is a figure which shows the structure of the table in AM. As shown in FIG. 3, the CAM stores a table showing a correspondence relationship between a 48-bit MAC address, 2-bit cast information, and 8-bit port number. Here, in the cast information, "00" is unicast and "0".
1'represents multicast and '10' represents broadcast.

Further, the network frame repeater shown in FIG. 2 outputs a header information of the network frame, that is, a header bus (Header Bus) 11_ to which the destination address and the source address are output.
1 and a switched bus (Switched Bus) 11_2 to which the frame data following the header is output.

The operation of this network frame repeater will be described below. The configuration of this network frame repeater will be described together with its operation.
When a network frame is transmitted to one of the n port controllers 12_1, ..., 12_n, for example, the port controller 12_1, the port controller 12_1 receives the search request signal (Search).
h Request) is output to the sequencer 21. The sequencer 21 includes buses 11_1 and 11_2 and a CA.
Judging free information of M15, etc., the port controller 12
_1 may occupy the bus, the search grant signal (Sear) may be directed to the port controller 12_1.
ch Grant) is output. Port controller 1
When 2_1 receives the Search Grant, the destination address (DA; Destination Address) in the transmitted network frame indicating the destination of the network frame.
Is output to the header bus 11_1. At the same time, the sequencer 21 receives the input port (IP; Inp) of the CAM 15.
A write signal (write) is output to ut Port), whereby the search by the destination address is performed in the CAM 15. CAM15
Is a hit / miss-hit signal (hit / hit) indicating whether or not the address data corresponding to the destination address is stored in the CAM 15 as a result of the search.
(miss) is returned to the sequencer 21. Sequencer 21
At this time, the output port (OP; Out of the CAM 15
The type of the destination address (unicast, multicast, or broadcast) read from the put port) is received as a cast signal (cast), and the sequencer 21 receives the result of hit / miss as follows. Perform processing.

(1) If the destination address is a multicast address, the sequencer 21
Is the port controller to which the network frame was sent (port controller 12_1 in this example)
To the switched bus 11 in response to the read signal (Read) sent to the port controller 12_1.
The frame data is output to _2. At the same time, the sequencer 21 sends the write signal (Wr
ite). As a result, the port controller 12
The frame data is transferred from _1 to the packet memory 17.

In the case of multicasting, the handling of the frame data differs depending on the user, so that the frame data is transferred to the packet memory 17 and the subsequent processing is entrusted to the CPU 24, as in the conventional case. (2) When the destination address is a unicast address, the sequencer 21 sends a read signal to the output port of the CAM 15 to transfer the frame data to the destination port to which the destination terminal is connected. Send control signal. Then CA
The M15 outputs the destination port number from its output port OP according to the control signal, and the port number is input to the decoder 22. Further, the sequencer 21 outputs an enable signal (Enable) to the decoder 22, and the decoder 22 receives the signal and decodes the port number to write to the port controller (for example, the port controller 12_n) of the destination port. The signal is output.
The write signal is input to the port controller of the destination port. Along with this, the sequencer 21 outputs a read signal to the port controller (port controller 12_1 in this example) of the source port (port to which the network frame is sent), and the port controller 12_1 responds to this by switching bus. The frame data is output to 11_2. This frame data is received by the port controller (port controller 12_n in this example) to which the write signal output from the decoder 22 is input, and is transmitted to the LAN connected to the port controller 12_n. (3) If the destination address is a broadcast address, or if the destination address is not registered in the table in the CAM 15 (misses), the sequencer 21
Outputs a write signal to the input port IP of the CAM 15. The port controller 12_1 outputs to the header bus 11_1, following the destination address, a source address indicating the source of the network frame, and the CAM 15 receives the write signal from the sequencer 21 and, in the future, outputs it. A search is performed based on the source address. When the search based on the source address is successful (hit), the sequencer 21
This time, the read signal and the control signal are output to the output port OP of the CAM 15, and the CAM 15 receives the control signal and receives the highest priority hit address (HHA; Highest Hit A) from the output port OP.
output). With this HHA, there were multiple hits in the search by source address (CAM15
If there are a plurality of tables matching the source address in the table in the above), it indicates the highest priority address according to a predetermined priority order among the plurality of table addresses. However, considering the meaning of the source address, if there are multiple hits, there is an error in the table configuration.

When the table structure is correct and only one hit is found by the search by the source address, the address of the table hit by only one becomes the HHA. This network frame repeater has a table memory 2 storing the entry port table shown in FIG.
3 is provided and HHA output from CAM15
Is input to the table memory 23, and the destination port information stored in the memory area corresponding to the input HHA is output from the table memory 23. In this destination port information, 1 bit is assigned to each port, and it becomes a write signal to each port controller as it is. The sequencer 21 outputs the read signal to the source port controller (the port controller 12_1 in this example), and the source port controller 12_1 outputs the frame data to the switched bus 11_2. The frame data output to the switched bus 11_2 is
The above-described destination port information for the HHA is received as it is by one or more destination ports written as a write signal, and the destination port information is received via the LAN (see FIG. 4) connected to the destination port. It is sent to the terminal.

Two entry port tables are stored in the table memory 23, one of which is always in an active state which is a target of access in a normal routine, and the other is a target of access in a normal routine. It is in the inactive state. In revising this entry port table, the CPU 24 rewrites the entry port table in the inactive state by learning the MAC address, and when the rewriting is completed, the sequencer 21 changes the table to the control bus (ta).
ble bus). Then, the sequencer 21 sends a switch signal (Switch) to the table memory 23 to change the table in the inactive state up to the active state and the table in the active state up to the inactive state. . In this way, the table memory 23
The entry port table stored in is updated.

The table in the CAM 15 is also constantly updated, but this update is the same as the conventional one, and detailed description thereof will be omitted.

[0029]

As described above, the present invention stores information indicating the correspondence between the address of a terminal and the port that sends the data when the terminal becomes the source of the data. For this reason, extremely high-speed data transfer is possible even in broadcasting in which the so-called VLAN concept is introduced.

[Brief description of the drawings]

FIG. 1 is a table showing correspondence between an address of a terminal and a port to which a terminal which is a receiver of a network frame when the terminal is a source is connected, in an embodiment of the network frame repeater of the present invention. It is a schematic diagram which shows the process.

FIG. 2 is a block diagram showing the configuration of an embodiment of a network frame relay device of the present invention.

FIG. 3 is a diagram showing a structure of a table in a CAM.

FIG. 4 is a circuit block diagram showing a configuration example of a conventional network frame repeater.

FIG. 5 is a schematic diagram for explaining the concept of VLAN.

[Explanation of symbols]

11_1 Header Bus (Header Bus) 11_2 Switched Bus (Switched Bu)
s) 12_1, ..., 12_n Port controller 15 CAM 17 Packet memory 21 Sequencer 22 Decoder 23 Table memory 24 CPU

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Yoshizawa 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Inside Kawasaki Steel Works (72) Inventor Yoshihiro Ishida 2-3-2 Uchisaiwaicho, Chiyoda-ku, Tokyo Saki Steel Co., Ltd.

Claims (3)

[Claims] 1. One or more terminals, each of which can be a source or a destination of a network frame as a block of information, including a source address representing a transmission source and a destination address representing a reception destination are connectable. A network frame repeater that has a plurality of ports for transmitting and receiving network frames, and transmits a received network frame received at any port from a port to which a terminal that is the receiving destination of the received network frame is connected An associative memory for storing the address of the terminal connected to the port and searching for the same address as the destination address or the source address included in the received network frame, Inside or associative memory In a memory different from the memory, the correspondence relationship between the address of the terminal receiving the network frame and the port to which the terminal receiving the network frame is connected, and the address of the terminal sending the network frame and the address of the terminal sending the network frame The information indicating the correspondence relation with the port to which the terminal of the destination of the network frame transmitted from is connected is stored, and the associative memory is searched based on the destination address or the source address included in the received network frame. And an address conversion circuit that specifies a port for transmitting the received network frame based on the information, and a transmission control circuit that transmits the received network frame from the port specified by the address conversion circuit. In a network frame characterized by Vessel. 2. The associative memory stores a correspondence table between an address of a terminal connected to the port and a port to which the terminal is connected, and the address conversion circuit includes the associative memory. At the same time, in the associative memory, at the address corresponding to the address in which the address of the terminal connected to the port is stored, the information indicating the port to which the terminal receiving the network frame transmitted from the terminal is connected is stored. The network frame repeater according to claim 1, further comprising: 3. The network frame repeater according to claim 2, wherein the information indicating the port is represented by a bit pattern in which each bit is associated with each port.