JP3003667B2 - Packet relay device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packet communication method for exchanging data between devices connected to a communication network by using data called a packet obtained by adding destination information to data to be transferred in data communication. The present invention relates to a packet relay apparatus having a plurality of inputs and outputs, and relaying a packet therebetween using the destination information thereof.

[0002]

2. Description of the Related Art FIG. 2 is a diagram showing a configuration example of a conventional packet relay device. Hereinafter, the operation of the packet relay will be described with reference to FIG. Note that the input buffer unit 12 is configured by a first-in first-out memory (hereinafter, referred to as a FIFO memory), and it is assumed that once read data cannot be referred to again. (1) When a packet is sent from the external communication line a to the relay device, the packet is extracted by the packet extraction unit 111 of the line input unit 11 and the data of the packet is written to the input buffer unit 12. Here, b is input packet data and a write control signal to the input buffer unit 12. (2) Next, the transfer control unit 14 sends a read signal d to the input buffer unit 12, and reads the header part of the packet (from the beginning of the packet to the destination information part) into the internal header storage 142. Here, c is output data of the input buffer unit 12. (3) The transfer control unit 14 sends the destination information e in the header storage 142 to the route control unit 13. (4) The path control unit 13 determines the transfer destination using the destination information e, sends the transfer destination information to the internal combining unit 2, and waits for the completion of the setting. Here, f is a transfer destination designation and setting completion signal. After the setting of the internal coupling unit 2 is confirmed, a transfer permission signal j is sent to the transfer control unit 14. (5) When the transfer control unit 14 receives the transfer permission signal j,
First, the data in the header storage 142 is sent to the internal connection unit 2. g is transfer data and a transfer control signal. (6) The transfer control unit 14 monitors the packet data transferred by the transfer end detection unit 141, and reads the signal d from the input buffer unit 12 until the end of the packet data is detected.
And transfer the read data c to the internal coupling unit 2 (g). (7) When the transfer is completed, the transfer control unit 14 sends a transfer end signal k to the path control unit 13. Upon receiving the transfer end signal, the path control unit 13 sends a connection release request to the internal coupling unit 2. (8) The output unit 3 outputs the packet data sent from the internal coupling unit 2 to the external line i. Here, h is transfer data and a transfer control signal.

[0003]

However, the conventional packet relay apparatus has the following problems. (A) When the input buffer unit 12 is constituted by a FIFO memory, the head part of the packet data read out by the route control unit 13 to obtain the destination information is temporarily stored in another storage area, and the internal coupling unit 2 FI at the time of transfer in
Prior to reading from the FO memory, a mechanism for transferring the head portion is required. (B) It is desirable to discard a packet in which an error is detected at the time of reception and a packet for which destination information is not appropriate in the relay device and not to retransmit the packet to an external line. However, a mechanism for realizing the packet is complicated. (C) When the input buffer unit 12 is configured by a FIFO memory, when the line input unit 11 detects an error during the reception of a packet, a mechanism for discarding the already written packet up to the middle is realized. Is difficult. (D) Since the path control unit 13 needs to observe the read side of the input buffer unit 12, the control of the output side of the input buffer unit 12 is complicated, and the realization of a high-speed packet transfer mechanism by the internal coupling unit 2 is realized. Hindered. (E) In order for the internal coupling unit 2 to detect the end of the packet, it is necessary to observe the read side of the input buffer unit 12, so that speeding up of data transfer from the input buffer unit 12 to the internal coupling unit 2 is hindered. Have been. Therefore, an object of the present invention is to solve the conventional problems as described above by simplifying the read-side mechanism of the input buffer unit, and at the same time, transferring data from the input buffer unit to the output unit via the internal coupling mechanism. It is an object of the present invention to provide a higher performance packet relay device with higher speed.

[0004]

In order to achieve the above object, a packet relay device of the present invention uses an external communication line.
A line input unit for receiving packet data from the
An output unit for transmitting data to an external line;
An input buffer unit for holding packet data;
A path control unit that determines the data transfer destination
The packet data in the input buffer section.
A transfer control unit for reading and transferring;
An internal coupling unit that transfers packet data to the output unit.
A packet relay device comprising:
Is an input packet extractor that extracts input packets
And a destination for extracting destination information included in the input packet.
Information extraction unit and input packet to measure the input packet length
And the input buffer unit.
A packet buffer that holds the output packet and a destination
Index buffer that holds packet length information
And the path control unit is configured to
Packet using the destination information without waiting for the entire packet to arrive.
It is characterized by performing the process of determining the transfer destination of
You. This allows packet length information to be index buffered.
When the data is written to the
Confirm that the data has been inserted and transfer the data immediately.
High-speed data relay processing
become.

[0005] The transfer control unit transmits a packet
When transfer is not required, the path control unit
From the input buffer after issuing a connection release request
Another feature is that an empty reading section for reading is arranged.
That is, an instruction to discard a packet is issued from the route control unit 13.
When received, one packet of data is received from the input buffer unit 12.
It is possible to discard packets by reading empty data.
You. As a result, the input buffer unit 12
Can easily introduce a packet discarding mechanism.
It becomes possible.

[0006]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of a packet relay device according to a first embodiment of the present invention. In the embodiment of FIG. 1, a destination information extraction unit 112 is newly provided in the packet extraction unit 111 of the line input unit 11. By directly sending the destination information extracted by the line input unit 11 to the route control unit 13, a mechanism for reading the header portion from the conventional input buffer unit 12 to obtain the destination information becomes unnecessary. For this reason, the transfer control unit 14 does not need the header storage 142, and when transferring a packet, it is sufficient to simply read out the input buffer unit 12 and transfer it to the internal coupling unit 2; No control related to 142 is needed. Hereinafter, the operation of the packet relay will be described with reference to FIG. It is assumed that the input buffer unit 12 is formed of a FIFO memory, and cannot read data once read out.

(1) When a packet is sent from the external communication line a, the line input unit 11 extracts the packet and writes the packet data into the input buffer unit 12. Also, 1 (lowercase L (ell)) extracted by the destination information extraction unit 112 is sent to the route control unit 13. Note that b is input packet data and a write control signal to the input buffer unit 12. (2) The path control unit 13 determines the transfer destination using the destination information, sends the transfer destination information to the internal coupling unit 2, and waits for the completion of the setting. Then, after confirming the setting of the internal coupling unit 2, it sends a transfer permission signal j to the transfer control unit 14. Here, f is a transfer destination designation and setting completion signal. (3) Upon receiving the transfer permission signal, the transfer control unit 14 sends a read signal d to the input buffer unit 12 and reads out the packet data c in the input buffer unit 12. The read data is transferred to the output unit 3 via the internal coupling unit 2. Here, h is transfer data and a transfer control signal. (4) The transfer control unit 14 monitors the packet data transferred by the transfer end detection unit 141 and continues reading from the input buffer unit 12 until the end of the packet data is detected. (5) Upon detecting the end of the transfer, the transfer control unit 14 ends the reading of the input buffer unit 12, and the transfer end signal k
To the path control unit 13. Upon receiving the transfer end signal k, the path control unit 13 sends a connection release request to the internal coupling unit 2. (6) The output unit 3 outputs the packet data sent from the internal coupling unit 2 to an external line. Here, h is transfer data and a transfer control signal, and i is an external communication line output.

FIG. 3 is a block diagram of a packet relay apparatus according to a second embodiment of the present invention. In FIG. 3, a destination information extraction / packet length measurement unit 113 is newly provided in the packet extraction unit 111 of the line input unit 11, and a counter circuit 143 is newly provided in the transfer control unit 14. That is, the packet length is measured in the line input unit 11 and the information is transmitted to the transfer control unit 1 via the route control unit 13.
Send to 4. Note that m is destination information and packet length information, and n is packet length information. The transfer control unit 14 generates a timing (time) required for transfer by a simple counter circuit 143 based on the packet length information, and transfers the packet. For this reason, the transfer control unit 14 does not need a mechanism for monitoring packet data and detecting the end of transfer, so that the data transfer system from the input buffer unit 12 to the internal coupling unit 2 is simplified. Hereinafter, the operation will be described with reference to FIG.

(1) When a packet is sent from the external communication line a, the line input unit 11 extracts the packet and writes the packet data into the input buffer unit 12. b is input packet data and a write control signal to the input buffer unit. Also, the destination information extraction unit 113
The destination information extracted in step (1) and the packet length information measured by the packet length measuring unit 113 are sent to the path control unit 13 (m). (2) The path control unit 13 determines the transfer destination using the destination information, sends the transfer destination information to the internal coupling unit 2, and waits for the completion of the setting. f is a transfer destination designation and setting completion signal. After the setting of the internal coupling unit 2 is confirmed, the packet length information n is sent to the transfer control unit 14. (3) Upon receiving the packet length information n, the transfer control unit 14 sends a read signal d to the input buffer unit 12 and reads out the packet data c in the input buffer unit 12. The read data is transferred to the output unit 3 via the internal coupling unit 2. h is transfer data and a transfer control signal. (4) The transfer control unit 14 determines the time required to transfer the packet based on the packet length information n by the counter circuit 143.
, And the reading of the input buffer unit 12 is continued during that time. (5) Upon detecting the end of the transfer by the counter circuit 143, the transfer control unit 14 ends the reading of the input buffer unit 12, and sends a transfer end signal k to the path control unit 13. Upon receiving the transfer end signal, the path control unit 13 sends a connection release request to the internal coupling unit 2. (6) The output unit 3 outputs the packet data h sent from the internal coupling unit 2 as an external line output i.

FIG. 4 is a configuration diagram of a packet relay device according to a third embodiment of the present invention. In FIG. 4, a packet buffer 121 and an index buffer 122 are newly provided in the input buffer unit 12. That is, it has a packet buffer 121 for holding input packets and an index buffer 122 for holding destination information, and writes the destination information extracted by the destination information extracting unit 112 into the index buffer 122. The path control unit 13 monitors the index buffer 122 and
When there is data in 22, data is read out and the packet is transferred. Therefore, by providing a buffer between the line input unit 11 and the route control unit 13, each can be operated autonomously, and control is simplified. Even when short packets arrive continuously, the buffer reduces the time constraint of the path control unit 13.

FIG. 5 is a block diagram of a packet relay apparatus according to a fourth embodiment of the present invention. In FIG. 5, a packet buffer 121 for holding input packets and an index buffer 122 for holding destination information and packet length information are provided in the input buffer unit 12, and a counter circuit 143 is provided in the transfer control unit 14. . The destination information is written into the index buffer 122 by the destination information extracting unit 113 of the line input unit 11 when the destination information arrives from the external line a. When the end of the packet is detected by the line input unit 11, the packet length information is written into the index buffer 122. Destination information and packet length information are alternately written to the index buffer 122.

FIG. 7 is a flowchart showing the processing operation of the route control unit in FIG. The path control unit 13 monitors the presence or absence of data in the index buffer 122,
When data exists in the index buffer 122 (step 101), the path control unit 13 reads the index buffer 122 (step 102). The read data is destination information of the packet to which the line input unit 11 has written. Using this destination information, the output unit 3 of the transfer destination is determined (step 103). Route control unit 13
Monitors the presence or absence of data in the index buffer 122 again, and when there is data in the index buffer 122 (step 104), the path control unit 13 reads out packet length information from the index buffer 122 again (step 105). This packet length information is the information that the line input unit 11 has written in the index buffer 122.

Next, the route control unit 13 confirms the end of the previous packet transfer in the internal coupling unit 2 (step 10).
6) After the transfer of the previous packet is completed, the transfer destination information of the packet is transmitted to the internal coupling unit 2 (Step 107). After the internal coupling unit 2 is also set, the packet length information is transmitted to the transfer control unit 14 (Step 107). 108). The above operation is repeatedly executed. Thereby, control on the output side of the input buffer unit 12 is simplified. A simplified packet data transfer path within the device from the output side of the input buffer unit 12 to the input side of the output unit 3 via the internal coupling unit 2, which is important when configuring a high-performance packet relay device. So that
A high-performance packet relay device is realized. Since the line input unit 11, the route control unit 13, and the internal coupling unit 2 can perform independent control, the design can be simplified. The route control unit 13 can know the arrival of the data of the entire packet by the arrival of the packet length information. Therefore, the transfer destination is determined using the destination information without waiting for the arrival of the data of the entire packet (previous destination search). Can be performed.

Next, a fifth embodiment of the present invention will be described. Although a diagram of this embodiment is not shown, in this embodiment, when an error occurs during the reception of a packet to the line input unit 11, error information is output and the packet is discarded using the error information. . As a method of discarding packets,
(1) a method of erasing the packet data in the input buffer unit 12, (2) a method of performing idle reading of the input buffer unit 12 (a device based on a seventh embodiment described later), and (3) discarding in the output unit 3. There are ways to do that.

FIG. 6 is a diagram showing the contents of an address translation table used in a sixth embodiment of the present invention. In the sixth embodiment, the route control unit 13 detects inappropriate destination information. Packets for which inappropriate destination information is specified are discarded by the packet discarding method described in the fifth embodiment. Here, an example of a mechanism for detecting inappropriate destination information using an address conversion table will be described. An address conversion table shown in FIG. 6 is provided in the route control unit 13. The path control unit 13 draws a conversion table using the received destination information as an address. The conversion table has a bit indicating discard together with the transfer destination information. If the discard bit is 1, the destination packet is discarded because an inappropriate address is specified.

Next, a seventh embodiment of the present invention will be described. In the seventh embodiment, when a packet to be discarded is detected in the device according to the fifth embodiment or the sixth embodiment, the route control unit 13 does not send the transfer destination information to the internal coupling unit 2. That is, in a state where the input of the internal coupling unit 2 is not coupled to the output unit 3, the transfer request of the packet is transmitted to the transfer control unit 14. As a result, the transfer control unit 14 reads the input buffer unit 12, and the read data is not transferred anywhere because the internal coupling unit 2 is in the open state. As a result, the input buffer unit 12
Is performed, and the packet is discarded. With the mechanism of the present embodiment, a single discarding unit can be realized for the two types of packets in the fifth and sixth embodiments without requiring a special mechanism.

[0017]

As described above, according to the present invention,
As compared with a conventional packet relay device, a packet can be relayed by simple control, and a high-performance packet relay device can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a packet relay device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration example of a conventional packet relay device.

FIG. 3 is a configuration diagram of a packet relay device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a packet relay device according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a packet relay device according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing the contents of an address conversion table used in a sixth embodiment of the present invention.

FIG. 7 is a flowchart of a processing operation of a route control unit in FIG. 5;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... input part, 2 ... internal coupling part, 3 ... output part, 11 ... line input part, 12 ... input buffer part, 13 ... route control part, 14 ... transfer control part, 111 ... packet extraction part, 112 ... destination information Extraction unit, 113: destination information extraction / packet length measurement unit, 121: packet buffer, 122: index buffer, 141: transfer end detection unit, 142: header storage, 143: counter circuit, 145: address conversion table.

Continued on the front page (72) Inventor Tetsu Yagi Inside Nippon Telegraph and Telephone Corporation 3-2-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo (72) Inventor Takeshi Ogura 3-2-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Sun (56) References JP-A-6-224932 (JP, A) JP-A-3-209947 (JP, A) JP-A-9-247213 (JP, A) JP-A-10-13434 (JP, A) JP-A-11-32052 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04L 12/56

Claims (2)

(57) [Claims] A line input unit for receiving packet data from an external communication line; an output unit for transmitting the packet data to an external line; an input buffer unit for holding the packet data waiting to be transferred; a route control unit for determining a transfer destination, the input by receiving the transfer permission
Transfer that reads and transfers the packet data in the buffer
A packet relay device comprising: a control unit; and an internal coupling unit that transfers packet data from the transfer control unit to the output unit, wherein the line input unit includes an input packet extraction unit that extracts an input packet. A destination information extraction unit for extracting destination information included in the input packet;
An input packet length measuring unit to be measured, and the input buffer unit holds the extracted packet.
Packet buffer and destination and packet length information.
And an index buffer to be held, respectively, and the path control unit does not wait for the entire packet to arrive.
A process for determining a destination of packet data transfer using the destination information
Packet relay device according to feature to make a sense. 2. The transfer control unit according to claim 1, wherein the transfer of the packet is
When unnecessary, connect to the internal connection from the path control unit
Empty read from the input buffer after requesting
2. An empty reading unit for performing the reading is arranged.
Packet relay device.