JP3299095B2 - Network frame relay device and network frame relay system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network frame relay device provided in a network system for relaying the transmission of a network frame, for example, a so-called port controller or bus bridge controller, and a network using the device. It relates to a frame relay system.

[0002]

2. Description of the Related Art Conventionally, in a network system,
For example, there is a network frame relay system called a hub or the like that relays transmission of a network frame as a block of information transmitted and received in the network. FIG. 13 is a circuit block diagram showing a configuration example of a conventional network frame relay system.

The network frame relay system 10 shown here is connected to n port control blocks 12_1,..., 12_n connected to a bus 11, and each port control block 12_1,
, 12_n are LAN13_1, ..., 13_, respectively.
n, a plurality of terminals A, B,..., C;.
..., G are connected.

This network frame relay system 1
Reference numeral 0 denotes a system that relays transmission and reception of a network frame extending over a plurality of port control blocks. The bus 11 has a CPU 14 for controlling the entire network frame relay system 10, an associative memory (content addressable memory; CAM) 15 for converting a destination address, which will be described later, into a port number, and a transmitted network. A packet memory 16 for temporarily storing frames is provided.

[0005] The network frame relay system is usually provided with various devices and the like. However, since they are not directly related to the description here, their illustration and description are omitted. Here, LAN
13 From terminal B connected to LAN 13 It is assumed that certain information in the form of a network frame is transmitted to the terminal E connected to n.

At this time, the network frame contains
Indicates the destination of information reception, that is, terminal E
Destination address, information source, and
That is, the source address indicating the terminal B is recorded.
Terminal B to LAN 13 1 that was sent via
The network frame is port control block 1
2 1 and then via the bus 11
It is stored in the memory 16. After that, the CPU 14
Of the network frame stored in the
From the header part to the data transfer destination (in this example, the terminal
Extract the destination address that represents E)
Send to CAM15. CAM15 has this network
Each terminal A, B,..., C;.
F,..., G and their respective terminals A, B,.
Which port control block 12 is F, ..., G
1, ..., 12 Indicates whether the connection has been established via n
The port number is stored in the CAM15
Enter the destination address and enter
Port indicating the connection destination of the terminal indicated by the
Output the default number.

[0007] By this port number, in this example, the port
Remote control block 12 n is this network
Network frame received by the LAN 13 output to n
Recognize that this is a network frame to be performed. This
The port number is output from the CAM 15 as in
And the network from the packet memory 16
Network frame via the bus 11
Le Block 12 n and its port control
Le Block 12 n and the LAN 13 through n
Transmitted to the terminal E.

[0008]

In the conventional network frame relay system, the relay of the network frame is generally performed according to the above-described procedure. 1 and the packet memory 1 via the bus 11
6 and then the destination address in the network frame stored in the packet memory 16 is sent to the CAM 15 via the bus 11, and the network frame stored in the packet memory 16 is further transferred via the bus 11 Port control block 12
n for a single relay
1 is used many times, so that it takes a long time to relay the network frame, and there is a problem that the communication speed is reduced.

[0009] In view of the above circumstances, the present invention
It is an object to provide a network frame relay device suitable for relaying a network frame in a short time, and a network frame relay system for relaying a network frame in a short time using the device.

[0010]

According to the present invention, there is provided a network frame relay device for relaying a transmission of a network frame as a block of information to which a header including a destination address indicating a destination is added. In a network frame relay device, first and second terminals for inputting and outputting a network frame between each other, and destination address extracting means for extracting a destination address from a network frame input from the first terminal And a third terminal for outputting a destination address extracted from the network frame input from the first terminal by the destination address extracting means.

Here, in the above-mentioned network frame relay device of the present invention, the destination address extracting means extracts a destination address from a network frame inputted from a first terminal, and a second destination address extracting means. The network frame input device extracts the destination address from the network frame input from the terminal of the network frame, and the network frame relay device is input from the second terminal by the destination address extracting means. Ru der those with a fourth terminal for outputting the destination address extracted from the network frame.

Further, the network frame of the present invention described above
A relay device for relaying the transmission of the network frame as a chunk of information, the relay device having a header including a source address indicating a source and a destination address indicating a destination; First and second terminals for inputting / outputting the data, address extracting means for extracting a source address and a destination address from a network frame input from the first terminal, and address extracting means for extracting the source and destination addresses from the first terminal. A third terminal for outputting a source address and a destination address extracted from the input network frame may be provided.

In this case, the address extracting means extracts the source address and the destination address from the network frame inputted from the first terminal, and extracts the network frame inputted from the second terminal. Also extracts a source address and a destination address from the network frame. The network frame relay device is extracted from the network frame input from the second terminal by the address extracting means. der those with a fourth terminal for outputting the source address and destination address Ru.

[0014]

[0015]

Further, nets <br/> work frame relay system of the present invention to achieve the above object, a header containing a destination address representing a destination is attached, transmitting network frames as chunks of information A network frame relay system comprising: a plurality of network frame relay devices for relaying a network address; and a plurality of information conversion devices for converting a destination address into information indicating a network frame relay device to which a network frame is to be transmitted. Each of the frame relay devices has first and second terminals for inputting and outputting a network frame between each other, and a destination address extracting means for extracting a destination address from the network frame input from the first terminal. And a third terminal for outputting a destination address extracted from the network frame input from the first terminal by the destination address extracting means, and at least one of the network frame relay devices. First
The destination address extracting means of the network frame relay device extracts the destination address from the network frame input from the first terminal, and also extracts the network address input from the second terminal. A destination address is extracted from the network frame, and the first network frame relay device extracts the destination address extracted from the network frame input from the second terminal by the destination address extracting means. A fourth terminal for outputting a nation address, the network frame relay system comprising: a second terminal of the first network frame relay device; and a first terminal of the network frame relay device. First and bus connecting the second terminal to each other of at least one second network frame relaying devices except Tsu network frame relaying devices,
The third terminal of the first network frame relay device and the third terminal of the second network frame relay device are connected to each other, and the destination address output from the third terminal is output from the information conversion device. A second bus to be sent to the first information conversion device, a first terminal of the first network frame relay device, and a first network frame relay device and a second network frame relay device among the network frame relay devices A third bus connecting the second terminals of at least one third network frame relay device excluding both, a fourth terminal of the first network frame relay device, and a third bus.
The third terminals of the network frame relay devices are connected to each other, and the destination address output from the fourth terminal to the third terminal is changed to the second information conversion device different from the first information conversion device. The first network frame relay device extracts a destination address from a network frame input from a first terminal and passes through a second bus to the information conversion device. And sends the network frame input from the first terminal to the first bus and sends the destination address from the network frame input from the second terminal to the first information conversion device. Extract and fourth
And the network frame input from the second terminal is output to the third bus via the second bus, and the second network relay device transmits the network frame from the first terminal to the second information conversion device via the first terminal. A destination address is extracted from the input network frame, sent to the first information conversion device via the second bus, and outputs the network frame input from the first terminal to the first bus. And the third network relay device extracts a destination address from a network frame input from the first terminal and sends the destination address to the second information conversion device via the fourth bus. And sending the network frame input from the first terminal to the third bus.

[0017] Here, upper pressure rams Tsu network frame relay system relays the transmission of the network frame header including destination address representing a source address and a destination representing the source is attached, as a mass of information Register the correspondence between a plurality of network frame relay devices, addresses and network frame relay devices, and set the destination address as
The information is converted into information indicating the network frame relay device to which the network frame is to be transmitted, and whether or not the correspondence between the source address and the network frame relay device is registered is searched. In a network frame relay system including a plurality of information conversion devices for registering correspondence, each of the network frame relay devices includes a first terminal and a second terminal for inputting and outputting a network frame between each other, and a first terminal. Address extraction means for extracting a source address and a destination address from a network frame input from
A third terminal for outputting a source address and a destination address extracted from the network frame input from the first terminal by the address extracting means, and a third terminal for outputting at least one of the network frame relay devices. The address extracting means of one network frame relay device extracts a source address and a destination address from a network frame input from a first terminal, and extracts a network frame input from a second terminal. Also extracts the source address and the destination address from the network frame, and the first network frame relay device is inputted from the second terminal by the address extracting means. A fourth terminal for outputting a source address and a destination address extracted from the network frame, the network frame relay system comprising: a second terminal of the first network frame relay device; and a fourth terminal of the network frame relay device. A first bus connecting the second terminals of at least one second network frame relay device excluding the first network frame relay device, and a third bus of the first network frame relay device
And the third terminal of the second network frame relay device are connected to each other, and the source address and the destination address output from the third terminal are sent to the first information conversion device among the information conversion devices. A second bus, a first terminal of the first network frame relay device, and at least one first of the network frame relay devices excluding both the first network frame relay device and the second network frame relay device; A third bus connecting second terminals of the third network frame relay device, a fourth terminal of the first network frame relay device, and a third terminal of the third network frame relay device; And output from the fourth terminal to the third terminal. And a fourth bus for transmitting the source address and the destination address to a second information conversion device different from the first information conversion device among the information conversion devices, wherein the first network frame relay device includes a first bus. A source address and a destination address are extracted from the network frame input from the terminal and sent to the first information conversion device via the second bus, and the network frame input from the first terminal is output to the first terminal. And a source address and a destination address extracted from the network frame input from the second terminal and sent to the second information conversion device via the fourth bus. For outputting a network frame input from a terminal of the third bus to a third bus Yes, the second
Network relay device extracts a source address and a destination address from a network frame input from a first terminal and sends the extracted source address and destination address to a first information conversion device via a second bus. And the network relay device outputs the source address and the destination address from the network frame input from the first terminal. Then, the network frame may be sent to the second information conversion device via the fourth bus, and the network frame input from the first terminal may be output to the third bus.

[0018] Incidentally, in the Netw network frame relay system of the present invention, the first network frame relay device, a connection state of a terminal connected to the second network frame relay device or the third network frame relay devices It is preferable to have a mailbox register that can be written and read from both the first bus side and the third bus side for storing.

[0019]

Embodiments of the present invention will be described below. FIG. 1 is a circuit block diagram showing an embodiment of the network frame relay system of the present invention, which includes one embodiment of the network frame relay device of the present invention.

The network frame relay system 20 shown in FIG. 1 is provided with two buses, a first bus 21 and a second bus 22. The first bus 21 has a plurality of port control blocks 23 provided therein.
1, ..., 23 n is a bus used for relaying a network frame over any two on n. The second bus 22 is connected to each port control block 23 as described later. 1, ..., 23 The bus through which the source address and the destination address extracted in n are transmitted.

Each port control block 23 1,
…, 23 n is the network frame relay data of the present invention.
Device, each port control
Lock 23 1, ..., 23 n is the first terminal 23
1 1, ..., 23 n 1, each second terminal 23 1
2, ..., 23 n 2, and each third terminal 23 1
3, ..., 23 n 3, each of the first terminals
23 1 1, ..., 23 n 1 is each LAN 24 1,
…, 24 n and each second terminal 23 1 2,
…, 23 n 2 are connected to a first bus 21 and each third
Terminal 23 of 1 3, ..., 23 n 3 is the second bus 22
It is connected to the. Each LAN 24 1, ..., 24 to n
Are a plurality of terminals A, B, ..., C; ...; E, F,
..., G are connected. Also, the first bus 21 has
C which controls the entire network relay system 10
PU25 temporarily stores network frames as needed.
The memory 28 to be stacked and the
Control block 26 is connected,
A destination address is provided on the second bus 22.
A CAM 27 that converts the information to a port number is connected.
Have been. CAM (associative memory) itself is widely used.
Because it is well known, description of itself is omitted here.
You.

The bus arbiter 29 controls the first bus 21.
It plays the role of controlling the authority, CPU 25 and
From the routing control block 26
Input a request signal indicating a request to use the bus 21
At the same time, only one of them uses the first bus 21.
It outputs a grant signal indicating use permission. Here, L
AN24 1 through port control block 23
1 from the terminal B connected to through n
Port control block 24 n connected to terminal n
To the network frame where the specified information is stored.
Shall be transmitted.

FIGS. 2 and 3 show examples of the data structure of the network frame. As shown in FIGS. 2A and 3A, a preamble for synchronization and a start delimiter for determining a start point of the network frame are added to the network frame in order from the front end in the transmission direction. Then, in the data link layer (MAC), a MAC destination address designating a receiving terminal (here, terminal E 2 ) and a MAC source designating a transmitting terminal (here, terminal B) in the data link layer. A header consisting of an address and information which is information to be actually transmitted are continuous. As shown in FIG. 3A, for example, a header of the IP layer also exists inside the information, and an IP destination address which is a destination address in the IP layer may exist there.

Since the layer structure of the network frame is widely known, the description of the layer structure itself is omitted. 2 (B) to 2 (E) and 3 (B) to 3 (E)
Will be described below with reference to the flowchart of FIG. FIG. 4 is a cross-sectional view of FIG.
2 is a flowchart illustrating an operation sequence of the network frame relay system 20 illustrated in FIG. 1 when a network frame having the data structure illustrated in FIG. The operation sequence shown in FIG. 4 is stored in the form of a microprogram in the routing control block 26 shown in FIG.

FIG. 5 is a diagram showing the structure of data input to the CAM 27 via the second bus 22.
Is a diagram showing the structure of data stored in the CAM 27. A network frame having the data structure shown in FIGS. 2A to 3A is sequentially transmitted from the Port control block 23 via 1 1, the first terminal 23 1 Input from 1. Then, the port control block 23 In FIG. 1, as shown in FIGS. 2B and 3B-1, the MAC destination address of the network frame is extracted and the third terminal 23 is extracted. 1
3 is output.

The MAC destination address extracted at this time may be the MAC address of each terminal (for example, terminal E) or the MAC address of the network frame relay system 20 itself. Then, it is searched whether or not the MAC destination address just extracted indicates the network frame relay system 20 itself. To this end, as shown in FIG. 5B, the port control block 23_1 adds an additional bit '01' to the extracted MAC destination address, and
Is output to the bus 22.

At this time, in order to prevent a plurality of port control blocks from using the second bus 22 at the same time, a second bus is sent from the port control block that has received the network frame from the LAN side to the routing control block 26. After outputting a risk quest signal indicating that the user wants to use the second bus 22 and receiving a grant signal for permitting use of the second bus 22 from the routing control block 26, the M
Outputs AC destination address.

When the MAC destination address to which the additional bit '01' is added is input to the CAM 27 via the second bus 22, the search is started from the routing control block 26 to the CAM 27. Instructed search signal SRCH is sent, and CAM
At 27, a search is made for a match between the input data and the data stored inside the CAM 27.

As shown in FIG. 6, the MAC address of the relay system 20 to which the additional bit '01' is added is stored in the CAM 27. In the search in step (a) of FIG. , The MAC destination address to which the additional bit '01' is input, and the M of the relay system to which the additional bit '01' stored inside the CAM 27 are added.
A match or mismatch with the AC address is detected, and from the CAM 27 to the routing control block 26,
A hit / miss signal H / MH_ representing match (H) and mismatch (MH_) is output.

The routing control block 26 uses the hit / miss signal H / MH_ to generate a CA signal.
It is determined whether the MAC destination address sent to M27 is the MAC address of the network frame relay system 20 (step (b) in FIG. 4). Here, it is assumed that the MAC destination address sent to the CAM 27 is not the MAC address of the network frame relay system 20, and the description will be continued with reference to FIG. 2 among FIGS. 2 and 3. . The case of the MAC address of the relay system 20 will be described later.

This network frame relay system 2
If the MAC address is not 0, step (c)
Proceed to. In this step (c), using the MAC destination address extracted as shown in FIG.
Another search is performed. That is, in this case, a grant signal is output again from the routing control block 26 to the port control block 23_1. Then, the port control block 23_
1 is the already extracted MA, as shown in FIG.
This time, an additional bit '00' is added to the C destination address, and output to the second bus 22. This additional bit '00' indicates that the search is for a MAC address of a terminal connected to the relay system 20. As shown in FIG. 6, inside the CAM 27, each MAC address of a large number of terminals connected to the relay system 20, and a port number indicating which port (port control block) each terminal is connected to Is stored. Incidentally, inside the CAM 27,
As shown in FIG. 6, the correspondence between the address and the time aging field is also stored. This time aging field will be described later.

As described above, the MAC destination address to which the additional bit '00' is added is the CAM 27
When the search signal SRCH is input from the routing control block 26,
At the same time, the search is performed. When the hit / miss signal H / MH_ and the match (H) are indicated, the port number corresponding to the MAC address is also output.

In step (d), the routing control block 26 sets the hit / miss signal H / MH.
Recognize _. If there is no match (MH_), the MAC that matches the input MAC destination address
This means that the address is not registered in the CAM 27, that is, a terminal having such a MAC address does not exist in this network, and after a frame end process to be described later is started (step (e)), port control is performed. A discard signal is output to block 23_1 to delete the network frame, and the port control block 23_1 deletes the currently transmitted network frame.

In step (d), when the routing control block 26 confirms the match (H), the process proceeds to step (f), where the port number corresponding to the MAC address output from the CAM 27 is stored in the routing control block 26. The data is stored in a destination register of the internal DMA controller (DMAC). After that, a frame end process to be described later is started (step (g)), and then the process proceeds to step (h). In step (h), as shown in FIG. 2C, the routing control block 26 sets the port address indicating the port number of the receiving side so as to precede the MAC destination address of the network frame on the first bus 21. To the first bus 21 from the port control block 23_1 by the DMAC of the routing control block 26.
, The network frame is transferred to the port control block 23_n. When using the first bus 21, the bus arbiter 29
Its use has been coordinated.

Each port control block 23 1,
…, 23 n, each temporary buffer 23 1a,
…, 23 na is provided, and in the above example, the terminal
B to port control block 23 Sent to one
The top part of the network frame
Port control block 23 to n
Until the transfer is started, the temporary buffer 23
1a is temporarily on standby and when in that state,
By the DMAC of the
Thus, the DMA transfer of the network frame is performed.

In the port control block 23_n,
When a network frame having the data structure of FIG. 2C is transferred, the port control block 23_
n, as shown in FIG. 2 (D), adds a preamble and a start delimiter suitable for the LAN 24_n connected to the port control block 23_n to a position preceding the MAC destination address ,
LAN and type of network frame shown in FIG. 2 (D)
24_n.

The terminal E connected to the LAN 24_n
Is sent, and recognizes that the format network frames from the MAC destination address of the network frames to be received himself in shown in FIG. 2 (D) receives the network frame. Next, when a match is recognized in step (b) shown in FIG.
In the search in step (a) shown in FIG.
7, the MAC destination address sent to the network frame relay system 20 shown in FIG.
The case of the C address will be described with reference to FIG. 3 of FIGS.

The MAC destination address extracted by the port control block 23_1 (FIG. 3B
If -1)) is the MAC address of the relay system 20, the process goes through steps (a) and (b) in FIG. 4, further activates the frame end processing in step (i), and then proceeds to step (j). move on. In step (j), the IP destination address (FIG. 3 (B-2)) is extracted again by the port control block 23_1.
The extracted IP destination address has
Additional bit '1 X' indicating that a P address (X
May be either '0' or '1') and input to the CAM 27. Inside the CAM27, as shown in FIG. 6, the additional bit '1 X' is added, and the IP addresses of all the terminals connected to the system, the port to which the terminal is connected to each IP address port The CAM 27 detects a match or mismatch between the input IP destination address and the IP address stored inside the CAM 27 in the same manner as described above. The hit signal H / MH_ and the port number in the case of a match (H) are output. In response to the hit / miss signal H / MH_, the routing control block 26 determines whether the same IP address as the input IP destination address is stored in the CAM 27 (step (k)). ). Mismatch (MH_
In the case of ()), the discard signal is sent to the port control block 23_1. When the discard signal is sent, the port control block 23_1 deletes the currently input network frame.
On the other hand, if a match (H) is recognized in step (k), the DMAC of the port control block 26 operates, and the network frame being input to the port control block 23_1 is transmitted from the port control block 23_1 to the first bus. 21 and the memory 2
8 (step (l)).

The right to use the first bus 21 at this time is adjusted by the bus arbiter 29 as described above. The routing control block 26 transfers the network frame to the memory 28, and proceeds to step (m). In step (m), network management described below is performed on the network frame stored in the memory 28. Here, the routing control block 26 merely sends an interrupt signal to the CPU 25 via an interrupt control line (not shown), and network management is performed by the CPU 25 that has received the interrupt signal.

The network management refers to, for example, a process of decrementing TTL (Time to Live) during the formation of a network frame. The TTL means the lifetime of the network frame. The TTL is introduced to prevent the network frame from being sequentially transferred, for example, by searching for a destination and remaining indefinitely. This is for extinguishing the network frame.

The MAC address of the network frame relay system 20 is originally recorded in the portion of the MAC destination address in the network frame stored in the memory 28. the destination address, rewriting the MAC address of the terminal E which receives the network frame is rewritten further MAC address of the middle Tsugishi stem 20 the source address.

Thereafter, the routing control block 26 fetches the port number output from the CAM 27 (step (n)), and receives the port number before the MAC destination address of the network frame as shown in FIG. 2C. The port address representing the port number of the side (in this example, the port number of the routing control block 23 — n) is output to the first bus 21, and then the first bus 21 is output from the memory 28 by the DMAC of the routing control block 26. 21 and the port control block 23_n
Is forwarded to (step 0).

When the network frame having the structure shown in FIG. 3C is transferred to the port control block 23_n, the port control block 23_n, as shown in FIG. 3D, stores the MAC destination address (as described above). The MAC destination address is transmitted to the relay system 2 by the CPU 25.
0 is rewritten from the MAC address of the terminal E to the MAC address of the terminal E), a preamble and a start delimiter that are compatible with the LAN 24_n connected to the port control block 23_n are added, and FIG. Let L be a network frame of the form shown
Output to AN24_n. The terminal E connected to the LAN 24 — n recognizes that it is a network frame to be received by the MAC destination address of the network frame of the format shown in FIG. Receive.

FIG. 7 is a circuit block diagram showing a circuit portion for extracting a destination address from a transmitted network frame in the port control block shown in FIG. Here, the port control block 23 shown in FIG. 1 will be described. The network frame having the data structure shown in FIG. 2A to FIG. 1 through the port control block 23 1 is input to the first network adapter block 231. The network adapter block 231 generates a clock CLK so as to synchronize with the preamble portion of the input network frame, detects a start point of the network frame by a start delimiter following the preamble, and converts a network frame after the start point into a network frame. 8 as serial data
The bit is input to the shift register 232. At the same time, the generated clock CLK is also input to the shift register 232. The control block 23
3 is set in advance with a parameter indicating at which position of the network frame the destination address to be extracted is located, and the control block 233 receives the clock CLK generated by the network adapter 231 as input. Then, the frequency is divided by 1/8 and input to the shift register 232, and the cut control signal CTL indicating the timing of the start and end of the destination address to be extracted in the network frame is output to the cut logic 234. I do.

The shift register 232 sequentially takes in and shifts the serial data sent from the network adapter block 231 in synchronization with the clock CLK sent from the network adapter block 231, and shifts the serial data. In synchronization with the clock CLK1, that is, every time 8 bits of serial data are taken in, the 8-bit parallel data is converted into the cut logic 234 and the packet buffer 2
Output to 36. Based on the cut control signal CTL sent from the control block 233, the cut logic 234 passes only the destination address to be extracted from the data sequentially sent in 8-bit units from the shift register 232 in parallel. To the header buffer 235. Here,
It is assumed that the destination address to be extracted is not divided into bit units shorter than 8 bits.

Thus, the header buffer 235 stores only the data of the extracted destination address and source address, while the packet buffer 236 stores the preamble of the format shown in FIG. And the data of the entire network frame from which the start delimiter is deleted is stored. The data stored in the header buffer 235 and the packet buffer 236 are respectively transmitted to the second bus 2 at the above-described timing.
2. Output to the first bus 21.

In FIG. 7, the extraction of the destination address has been described, but the extraction of the source address is also performed in the same manner. FIG. 8 is a flowchart showing a routine executed by the CPU for deleting data registered in the CAM. The CPU 25 shown in FIG. 1 updates the contents of the time aging register (TAR) in the routing control block 26 every predetermined time (step (p)). In the example shown here, for example, every 10 minutes, the time aging registers are 1, 2,.
Are cyclically rewritten between 1 and 8, such as 1, 2,.

On the other hand, in the CAM 27, as shown in FIG. 6, the contents of the time aging register (TAR) at the time when the corresponding data is stored or at the time of retrieval are added to the correspondence between the address and the port number. Any one of numerical values 1 to 8) is stored for each corresponding data. This storage processing will be described later. When the contents of the time aging register (TAR) are updated in step (p) of FIG. 8, the process proceeds to step (q), and a PURGE signal for instructing erasure of data is sent from the CPU 25 to the CAM 27. The CAM 27 receives the PURGE signal and updates the updated time aging register (TA).
R) The data corresponding to the address and the port number having the time aging field that matches the content of the CAM 27
Is deleted from. That is, if the contents of the time aging register are updated from 1 to 2 this time, CAM2
The data having the time aging field in which the numerical value '2' is registered is deleted in FIG.

FIG. 9 shows steps (e), (g),
It is a flowchart of the frame end processing routine started in (i). This frame end processing is executed by the routing control block 26 shown in FIG.
When the frame end processing routine shown in FIG. 9 is started, first, it waits until the reception of the frame being received is completed (step (r)). This end of reception is determined by a reception end signal from the port control block receiving the frame. When the reception of the frame is completed, the process proceeds to step (s), and it is determined whether or not the received frame has an error. The determination of the presence or absence of this error is also made based on a signal from the port control block that has received the frame. If it is determined in step (s) that an error exists,
That is, without writing to the CAM 27,
finish.

When it is determined in step (s) that there is no error, the process proceeds to step (t), and the source address of the frame is output to the second bus 22. At this time, an additional bit '00' representing the MAC address is added to the head of the source address. The output of the source address to the second bus 22 is performed in the same manner as in the case of the output of the destination address, so that a plurality of port control blocks do not use the second bus 22 at the same time. A request signal indicating that the second bus 22 is to be used is output from the block to the routing control block 26, and after receiving a grant signal for permitting use of the second bus 22 from the routing control block 26, 2 outputs the MAC source address to the second bus 22.

When the search based on the MAC source address is performed, a match (H) and a mismatch (MH) are sent from the CAM 27 to the routing control block 26.
_- hit miss signal H / MH representing a) _- it is output. In the routing control block 26, the hit miss signal H / MH _- by, CAM27
It is determined whether or not the MAC source address sent to is registered in the CAM 27 (step (u)). If registered, the process proceeds to step (v) and the CAM 27
Of the current time aging register (TAR) is written in the time aging field corresponding to the MAC source address. This is the MAC
In response to the communication from the source address, the time aging field is rewritten so that data on the MAC source address is not deleted.

If it is determined in step (u) that the MAC source address is not stored in the CAM 27 (miss hit), the process proceeds to step (w),
The source address is added with an additional bit '00' indicating that it is a MAC address, is associated with the port number of the port control that has received the frame having the MAC source address, and further has a current time aging register (TAR). ) Is added and registered.

As described above, the information of the address which is never accessed during the cycle of the contents of the time aging register (TAR) is deleted from the CAM 27, and when accessed, the accessed data is replaced by the time of the access. From at least the time aging register (T
AR) is kept registered in the CAM 27 during one cycle. The information registered in the CAM 27 is deleted because it is necessary to delete the registration of the terminal that has stopped participating in communication, for example, when the power of the terminal is turned off.

Although the MAC source address has been described here, the same applies to the IP source address. FIG. 10 is a circuit block diagram showing another embodiment of the network frame relay system of the present invention. still,
In FIG. 8, each terminal A, B,.
, E, F,..., G are not shown.

The network frame relay system shown in FIG. 10 has two network frame relay sub-systems having the same configuration as the network frame relay system 20 shown in FIG. 1 except for a bus bridge control block (BBC) 30 shown in the center of the figure. The system is composed of systems 20A and 20B. Therefore, in FIG. 10, each block except the BBC 30 has the same reference numerals as those assigned to the constituent circuit blocks of the network frame relay system 20 shown in FIG. 1, and the two network frame relay subsystems 20A and 20B have the same reference numerals. FIG. 1 is a diagram to which reference numerals to which A and B are added are attached.
Of the network frame relay system 20 will be omitted, and only the BBC 30 will be described. Here, the buses on the network frame relay subsystem 20B side corresponding to the first bus 21A and the second bus 22A on the network frame relay subsystem 20A side are respectively referred to as a third bus 21B and a fourth bus 21B. Bus 22B.

The BBC 30 provided in the network frame relay system of FIG. 10 includes port control blocks 23_1A,..., 23_nA;
, 23_nB is an embodiment of the network frame relay device according to the present invention. This BBC3
0 is provided with four terminals, that is, a first terminal 30_1, a second terminal 30_2, a third terminal 30_3, and a fourth terminal 30_4. It is connected to a bus 21A, a second bus 22A, and a fourth bus 22B.

[0057] The BBC30, when viewed from the network frame relay subsystem 20A side acts port control block 23_1A constituting the network frame relay subsystem 20A, ..., the 23_nA the <br/> Similarly, the network frames When viewed from the relay subsystem 20B side, it operates similarly to each of the port control blocks 23_1B,..., 23_nB configuring the network frame relay subsystem 20.

Network frame relay subsystem 2
On the 0B side, for example, the port control block 23_1
When the network frame output from B to the third bus 21B is input from the first terminal 30_1 of the BBC 30 via the third bus 21B, the network frame is transmitted to the BBC 30 by, for example, the port control block 23_1A. As in the case of the input, the destination address is extracted from the input network frame, and the extracted destination address is sent to the CAM 27A via the third terminal 30_3 and the second bus 22A. After the above-described predetermined procedure, the network frame is transferred to the second terminal 30.
_2 to the first bus 21A.

On the other hand, the first bus 21 is connected to the BBC 30.
A, when a network frame is input via the second terminal 30_2, the BBC 30 also extracts a destination address from the network frame input from the second terminal 30_2,
The signal is sent to the CAM 27B via the fourth terminal 30_4 and the fourth bus 22B. After that, the network frame input from the second terminal 30_2 is output to the third bus 22B after the above-described predetermined procedure.

When a network frame is input from the first terminal 30_1 of the BBC 30 to the BBC 30, the bus on the network frame relay subsystem 20A side is not empty or the second terminal 30 of the BBC 30
_2, when a network frame is input to the BBC 30, the network frame relay subsystem 2
In some cases, the bus on the 0B side may not be empty.
To cope with this, the BBC 30 is provided with a temporary buffer 30a that can temporarily store one network frame as a whole.

The BBC 30 is provided with a mailbox 30b. Next, the mailbox 30b will be described. When a network frame is transmitted from a terminal on the network frame relay subsystem 20A side (for example, the terminal A) to a terminal on the network frame relay subsystem 20B side (for example, the terminal B), the network frame relay subsystem transmitted from the terminal A is transmitted. The network frame sent to 20A needs to be sent to the network frame relay subsystem 20B via the BBC 30. Therefore, the CAM on the network frame relay subsystem 20A side
27A, network frame relay subsystem 2
All terminals on the 0B side need to be registered in association with the port number of the BBC 30.

Similarly, in the CAM 27B on the network frame relay subsystem 20B side, the information needs to be registered for all the terminals on the network frame relay subsystem 20A side. In other words, even if the terminal connected to the network frame relay subsystem 20A is connected to the network frame relay subsystem 20A or the terminal connected to the network frame relay subsystem 20B, the two CAMs 27A , 27B need to be registered. Moreover, these two C
The information registered in the AMs 27A and 27B must always maintain consistency. For example, the information of the terminal X is CAM2
It must not be registered in 7A but not in CAM 27B.

By the way, as described above, the CPU 25A or the routing control block 26A on the network frame relay subsystem 20A side receives the C from the network frame relay subsystem 20A side.
The terminal information can be deleted or registered for the AM 27A, but the terminal information cannot be deleted or registered for the CAM 27B on the network frame relay subsystem 20B side. Therefore, the CPU 25A on the network frame relay subsystem 20A side
Writes the registered contents in the mailbox 30b of the BBC 30, when the above-mentioned source address is registered. Then, the BBC 30 inputs an interrupt signal to the CPU 25B on the network frame relay subsystem 20B side via an interrupt control signal line (not shown). Then, the CPU 25B knows that something has been written to the mailbox 30b of the BBC 30, reads the content, and registers it in the CAM 27B on its own side according to the content. By doing so, the two CAMs 27
A and 27B are always kept in a state where consistent information is stored.

FIG. 11 is a diagram showing the data structure of the mailbox 30b of the BBC 30 shown in FIG. Here, a bit indicating whether or not the information stored in the mailbox 30b is valid data is added to the address of the terminal to be registered.

For example, if the address of the terminal A connected to the network frame relay subsystem 20A is CAM2
When the address is newly registered in 7A, the address is written into the mailbox 30b of the BBC 30 together with the additional bit '1'. The network frame relay subsystem 20 having received the write notification by the interrupt signal
The CPU 25B on the B side is the mailbox 3 of the BBC 30.
0b, the information of the terminal A is to be registered, the information of the terminal A is registered in the CAM 27B on its own side, and the valid / invalid bit of the mailbox 30b of the BBC 30 is invalidated. Rewrite to 0 '. By doing so, the network frame relay subsystem 20
The side A can know that the contents of the mailbox 30b of the BBC 30 have been read by the network frame relay subsystem 20B side and that the mailbox 30b of the BBC 30 can be used again.

In this embodiment, writing data from the network frame relay subsystem 20A to the mailbox 30b of the BBC 30 and reading the data from the network frame relay subsystem 20B has been described. Writing data to the mailbox 30b of the BBC 30 from the side and reading the data from the network frame relay subsystem 20A side is performed in the same manner.

FIG. 12 is a diagram showing a connection method between the network frame relay subsystem and the BBC. FIG.
As described with reference to FIG. 0, a plurality of network frame relay subsystems can be connected by using the BBC. FIG. 10 is a diagram showing an example in which two network frame relay subsystems 20A and 20B are connected. However, three or more network frame relay subsystems may be connected by BBC.

FIGS. 12A and 12B show four network frame relay subsystems 20A and 20B.
This is an example of a network frame relay system including B, 20C, and 20D. As shown in FIG. 12A, a BBC is arranged so that a BBC is arranged between any two network frame relay subsystems. May be
As shown in FIG. 12B, a BBC may be arranged only between two adjacent network frame relay subsystems. In the case of the system as shown in FIG. 12A, for example, the
Network frames can be transferred to B, 20C, and 20D by one relay, but a large number of BBCs are required. In the case of the system shown in FIG. 12B, for example, in order to transfer a network frame from the subsystem 20A to the subsystem 20D, the subsystem 20A transmits the network frame to the subsystem 20B, the subsystem 20B transmits the network frame to the subsystem 20C, and the subsystem 20C transmits the network frame. It is necessary to perform the transfer to the subsystem 20D three times, and the transfer takes a corresponding amount of time, but the number of BBCs is small and an inexpensive relay system is constructed.

Incidentally, a relay system intermediate between FIGS. 12A and 12B may be constructed.

[0070]

As described above, according to the present invention, the destination address of the network frame transmitted by the network frame relay device is extracted and passed through the dedicated bus to the information conversion device (in the above example, the information conversion device). CAM), so that network frames can be relayed and transferred at high speed.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram illustrating an embodiment of a network frame relay system of the present invention including an embodiment of a network frame relay device of the present invention.

FIG. 2 is a diagram illustrating an example of a data structure of a network frame.

FIG. 3 is a diagram illustrating an example of a data structure of a network frame.

FIG. 4 is a flowchart showing an operation sequence of the network frame relay system when a network frame is transmitted.

FIG. 5 is a diagram showing a structure of data input to a CAM.

FIG. 6 is a diagram showing a structure of data stored in a CAM.

FIG. 7 is a block diagram of the port control block shown in FIG.
FIG. 3 is a circuit block diagram illustrating a circuit portion for extracting a destination address from a transmitted network frame.

FIG. 8: CP for deleting data registered in CAM
9 is a flowchart illustrating a routine executed in U.

FIG. 9 is a flowchart of a frame end processing routine.

FIG. 10 is a circuit block diagram showing another embodiment of the network frame relay system of the present invention.

11 is a diagram showing a data structure of a BBC mailbox shown in FIG. 10;

FIG. 12: Network frame relay subsystem and B
It is a figure showing the connection method with BC.

FIG. 13 is a circuit block diagram illustrating a configuration example of a conventional network frame relay system.

[Explanation of symbols]

20 Network frame in Tsugishi stem 20A, 20B, 20C, 20D network frame relay subsystem 21,21A first bus 22,22A second bus 21B the third bus 22B fourth bus 23_1, ..., 23_n; 23_1A , ..., 23_n
A; 23_1B, ..., 23n_B Port control blocks 23_1_1, ..., 23_n_1; 23_1_1A,
, 23_n_1A; 23_1_1B, ..., 23_n_
1B first terminals 23_1_2, ..., 23_n_2; 23_1_2A,
, 23_n_2A; 23_1_2B, ..., 23_n_
2B second terminals 23_1_3, ..., 23_n_3; 23_1_3A,
..., 23_n_3A; 23_1_3B, ..., 23_n_
, 24_n LAN 27, 27A, 27B Associative memory (CAM) 30 Bus bridge control block (BBC) 30_1 First terminal 30_2 Second terminal 30_3 Third terminal 30_4 Fourth terminal

Claims (5)

(57) [Claims] 1. A network frame relay device for relaying transmission of a network frame as a block of information, to which a header including a destination address indicating a destination is attached, wherein a network frame is input and output between the devices. And a second terminal; a destination address extracting unit for extracting a destination address from a network frame input from the first terminal; and a destination address input from the first terminal by the destination address extracting unit. Third output destination address extracted from the network frame
And the destination address extracting means comprises:
A destination address is extracted from a network frame input from the terminal of the second frame, and a destination address is extracted from the network frame also from the network frame input from the second terminal. Wherein the network frame relay device comprises a fourth terminal for outputting a destination address extracted from the network frame input from the second terminal by the destination address extracting means. Network frame relay device. 2. A network frame relay device for relaying transmission of a network frame as a chunk of information, to which a header including a source address indicating a transmission source and a destination address indicating a reception destination is attached, wherein the networks are interconnected. First and second terminals for inputting / outputting a frame; address extracting means for extracting a source address and a destination address from a network frame input from the first terminal; And a third terminal for outputting a source address and a destination address extracted from a network frame input from a terminal of the network frame. From source address And extracting the source address and the destination address from the network frame input from the second terminal, and extracting the source address and the destination address from the network frame. A network frame relay device, comprising: a fourth terminal for outputting a source address and a destination address extracted from a network frame input from the second terminal by the address extraction means. . 3. A destination ad indicating a receiving destination.
Network as a block of information with a header containing the address
Network frame that relays the transmission of a work frame
A plurality of relay devices and the destination address
Network frame to the destination of the network frame.
Information conversion to convert to information instructing the frame relay device
Network frame relay system with multiple devices
System, wherein each of the network frame relay devices
A first for inputting and outputting a network frame between each other;
A second terminal; and a network input from the first terminal.
Extract the destination address from the
Output destination address extracting means;
The first address is extracted by the destination address extracting means.
Extracted from the network frame input from the
Third terminal for outputting the output destination address
And at least one of the network frame relay devices.
And one of the first network frame relay devices
The destination address extracting means is provided at the first end.
From the network frame input from the
To extract the termination address,
To the network frame input from the second terminal
Also, the destination
And extracting the first address.
The network frame relay device is
Input from the second terminal by the location address extracting means.
Destinations extracted from the network frame
And a fourth terminal for outputting the first network address.
The second terminal of the network frame relay device;
And the network frame relay device
At least except for one network frame relay device
Also before one second network frame relay device
A first bus connecting the second terminals to each other;
The third end of the network frame relay device of
And the second network frame relay device
Connected to the third terminals of the
Converts the output destination address to the information
A second of the devices to send to the first information conversion device
A bus and the first network frame relay device
In the first terminal, and in the network frame
Relay device of the first network frame
Device and the second network frame relay device
At least one third network
Connecting the second terminals of the frame relay device
A third bus and the first network frame relay data;
A fourth terminal of the device and the third network.
Connecting the third terminals of the frame relay device
And the data output from the fourth terminal or the third terminal.
The destination address is stored in the information conversion device.
Second information different from the first information conversion device
A fourth bus for sending to the conversion device, wherein the first network frame relay device comprises:
In the network frame input from the first terminal
The destination address is extracted from the second
To the first information conversion device via the
The network frame input from the terminal 1
And the second terminal.
From the network frame input from the
Extraction address via the fourth bus
And sends it to the second information conversion device and the second terminal
The network frame input from the third bus
And the second network relay device is connected to the first terminal.
From the network frame input from the
Extraction address via the second bus
And sends it to the first information conversion device,
The network frame input from the
And the third network relay device further comprises: the first terminal.
From the network frame input from the
Extraction address via the fourth bus
And sends it to the second information conversion device,
The network frame input from the third
A network frame relay system for outputting to a network. 4. A source address indicating a transmission source and a reception address.
Header containing the destination address indicating the trustee
Of the network frame as a chunk of information
Multiple network frame relay devices that relay transmission
, Address and network frame relay device
Of the destination address
Network frame to the destination of the network frame.
And convert it to information that directs the frame relay device.
The source address and the network frame relay data
Search whether the correspondence with the device has been registered and
Information conversion to register the response when the response is not registered
Network frame relay system with multiple devices
System, wherein each of the network frame relay devices
A first for inputting and outputting a network frame between each other;
A second terminal; and a network input from the first terminal.
Source address and destination
Address extraction means for extracting an application address;
Input from the first terminal by the address extracting means
Source address extracted from the network frame
Output destination address and destination address
Terminal, and at least one of the network frame relay devices.
And one of the first network frame relay devices
Address extracting means for inputting the address inputted from the first terminal;
Source address and desktop
To extract the tination address
The network frame input from the second terminal
Source from the network frame.
Extract address and destination address
The first network frame relay device.
A chair from the second terminal by the address extracting means.
The software extracted from the input network frame
Output source address and destination address
A fourth terminal for connecting the first frame to the first frame.
The second terminal of the network frame relay device;
And the network frame relay device
At least except for one network frame relay device
Also before one second network frame relay device
A first bus connecting the second terminals to each other;
The third end of the network frame relay device of
And the second network frame relay device
Connected to the third terminals of the
The output source address and destination address
Dress to a first information conversion device of the information conversion device
A second bus for sending to the device, and the first network
A first terminal of the frame relay device;
The first network among the network frame relay devices.
Workframe relay device and second network
At least one, excluding both
The second network frame relay device of the second
A third bus for connecting terminals, and the first net;
The fourth terminal of the work frame relay device; and
The third network frame relay device of the third
3 terminals are connected to each other, and the fourth terminal or the third terminal
Source address and destination output from pin
Address of the information conversion device.
A second information conversion device different from the first information conversion device
And a fourth bus for sending to the first network.
A frame relay device is input from the first terminal.
Source address from the network frame
Extracting a destination address to the second bus
To the first information conversion device via the
The network frame input from the terminal of
And the second terminal
From the network frame input from
Extract dress and destination address before
Via the fourth bus to the second information conversion device
Network frame input from the second terminal
Output to the third bus, wherein the second network relay device is connected to the first terminal.
Source from network frame input from child
Extract address and destination address
The first information conversion device via the second bus
To the network network input from the first terminal.
Output to the first bus.
To the third network relay device, the first end
Source from network frame input from child
Extract address and destination address
The second information conversion device via the fourth bus
To the network network input from the first terminal.
A network frame relay system for outputting a frame to the third bus . 5. The first network frame relay data.
The device is the second network frame relay device.
Or the third network frame relay device.
Storing the connection state of a terminal connected to the first
Write and read from both the bus side and the third bus side
The network frame relay system according to claim 3 or 4 , further comprising a mailbox register that can be freely put out .