JP2616431B2 - Packet communication system and apparatus for load balancing - 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 system having a redundant configuration in an interface for performing communication by packets or an interface between terminal devices.

[0002]

2. Description of the Related Art A conventional device such as a router has a problem in that, when a plurality of serial interfaces are present between two devices, an I / O interface is required.
In layer 3 such as the P layer, a different interface is selected for each destination subnetwork.

[0003]

In the above-described conventional device such as a router, when a plurality of serial interfaces exist between two devices, the device is connected to a layer 3 such as an IP layer.
Since a different interface is selected for each destination subnetwork, there are the following two problems.

[0004] (1) Since the distribution of packets is performed for each destination subnetwork or for each call as disclosed in Japanese Patent Application Laid-Open No. 02-222340, only static load distribution can be performed regardless of the congestion state of the destination. (2) Since the distribution of the destination is performed irrespective of the traffic of the connection, the load may be concentrated on a specific line.

It is an object of the present invention to provide a packet communication system which solves the above problems and a communication device used for the same.

[0006]

In a packet communication system according to the present invention, communication devices are connected by a plurality of lines as communication paths between the communication devices, and communication between the communication devices is guaranteed regardless of which line is used. A packet transmitting unit for distributing a transmission packet from inside the communication device to a plurality of lines, and a packet to be transmitted to the inside of the communication device after multiplexing packets received from the plurality of lines. In a packet communication system having a receiving unit, a packet receiving unit of each communication device monitors a number of stored packets in a buffer memory for storing received packets, a value of the packet storage counter, and a buffer memory capacity. Has its own station congestion state notifying means for recognizing the congestion state inside the device from the comparison of The packet transmitting unit of each of the communication devices has a congestion state specifying unit that explicitly indicates a congestion state of the packet receiving unit in a congestion notification area provided in the packet, and the packet receiving unit includes The communication device further includes a congestion status notifying unit for recognizing the congestion state of the communication apparatus on the other side for each line by looking at the congestion notification area defined above, and notifying a packet transmitting unit of the result. According to the packet congestion notification of the other communication device from the packet receiving unit, the unit should output the packet to be transmitted to which line, or should notify the signal regulating the transmission to the buffer memory control unit inside the device Selecting means, and in addition, each of the communication devices,
When the other communication apparatus is congested, it has a packet load balancing control unit that makes note of the output of the packet to the packet transmission unit, the operation in the packet load balancing control unit, the path
It is performed autonomously every time a packet is sent and received.

[0007]

The local station congestion status notifying means judges the congestion status of the packet receiving unit from the contents of the packet accumulation counter, and notifies the packet transmitting unit of the congestion when the congestion occurs. Information indicating congestion is written into the congestion notification area of the transmission packet by the explicit means, and a request is made to the other communication apparatus for load distribution of traffic so that the load is not concentrated on a specific line.

Further, the other station congestion state notifying means of the packet receiving unit detects the congestion notification information written on the packet by the other unit packet transmitting unit, avoids the congested line, and sets the same destination device. By transmitting the packet to another line toward the destination, the distribution of the packet is performed according to the congestion situation of the other party. However, when all the lines going to the same destination are congested, the packet load distribution control unit transmits a transmission restriction signal inside the communication device,
The transmission of the packet from the packet transmission unit is temporarily stopped.

In this way, the load of packets on the serial interface of the information communication device can be flexibly distributed according to the congestion state of the communication device, packet discarding due to congestion can be suppressed at the network level, and the network throughput can be reduced. It is possible to raise.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a packet communication system for performing load distribution according to the present invention, and FIG. 2 is a block diagram showing an input / output terminal of a communication apparatus used in the embodiment of FIG. 1 in detail. The communication devices 11, 12, 13, and 14 are switching devices or terminal devices. The devices are connected to each other by a plurality of bidirectional links to form a network, and traffic load among the communication devices can be balanced. It has a configuration.

The input / output terminals of the communication devices 11, 12, 13, and 14 are composed of the same type of packet transmitting unit 10 and packet receiving unit 20 as shown in FIG. That is, the packets input to the packet receiving unit 20 from the transmission lines 102a and 102b are input to the packet receiving processing units 4a and 4b, respectively, and are input to the buffer memories 3a and 3b after being identified as significant packets. .
At this time, the packet reception processing units 4a, 4b notify the packet reception to the packet accumulation number counters 5a, 5b (which may be provided separately) in the buffer memory via the control lines 108a, 108b (for example, Up).

On the other hand, the packet read control units 6a and 6b
The packets stored in the buffer memories 3a and 3b are alternately read out, output to the communication paths 106a and 106b, and read out of the control lines 107a and 1b.
The counters 5a and 5b are notified via 07b (for example, count down). The selector 8 has a communication path 10
6a and 106b, and multiplexes packets coming from
4 to the inside of the communication device.

The counters 5a and 5b are provided in the buffer memory 3
The number of packets in the packets a and 3b is managed. If this number exceeds a certain value, a packet overflow warning signal is sent to the packet transmission unit 1 via the control lines 110a and 110b.
0 to the congestion notification control units 1a and 1b. The congestion notification controllers 1a and 1b explicitly write that congestion has occurred in a congestion notification area provided in a packet. The packet is transferred to the communication device on the other side that caused the packet congestion through the transmission paths 101a and 101b, so that the communication device on the other side knows that congestion has occurred due to its own transmission packet. The congestion notification area of the packet here is premised on the content of the contradiction in the network, and any area may be assigned as long as it does not affect the protocol used in the network.

The congestion notification explicitly described in the packet as described above is detected by the packet reception processing units 4a and 4b of the communication device on the packet receiving side, and the congestion state of the other side is controlled by the control lines 109a and 109b. The opposite device state management unit 7 recognizes this, and controls the selector 2 of the packet transmission unit via the control line 111. The selector 2 is connected to the control line 11
The packet received from the inside of the apparatus via the communication path 103 is referred to the communication path 105 by referring to the congestion state of the link indicated by No. 1.
a or 105b is selected.
If both links (and if there are more links, both links) are congested, the control line 112 is used to regulate the transmission of packets from inside the device.
Activate the regulatory signal.

According to the above configuration, load sharing can be performed using a plurality of links between communication devices, and
Packet transmission is restricted by the congestion state of the partner device, so that packet discarding due to congestion in the entire network can be minimized and the network throughput can be increased.

[0016]

As described above, according to the present invention, communication apparatuses are connected by a plurality of lines, load is distributed according to the congestion state of the lines, and packet discarding due to congestion in the entire network is minimized. Therefore, there is an effect that it is possible to increase the network throughput.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a packet communication system for performing load distribution according to the present invention.

FIG. 2 is a block diagram showing an input / output end of a communication device used in the embodiment of FIG. 1 in detail;

[Explanation of symbols]

11, 12, 13, 14 Communication device 1a, 1b Congestion notification control unit 2 Selector 3a, 3b Buffer memory 4a, 4b Packet reception processing unit 5a, 5b Packet storage number counter 6a, 6b Packet read control unit 7 Opponent device state management unit 8 selector 101a, 101b transmission line 102a, 102b transmission line 103, 104, 105a, 105b, 106a, 10
6b Communication path 107a, 107b Control line for notifying packet readout 108a, 108b Control line for notifying packet reception 109a, 109b Control line for notifying congestion status of other party 110a, 110b Control line for warning of packet overflow 111 Control for selector Line 112 Control line for packet transmission regulation

Claims (2)

(57) [Claims] 1. A communication path between communication devices, wherein the communication devices have a communication device interface such that communication devices are connected by a plurality of lines and communication between the communication devices is ensured regardless of which line is used. In a packet communication system having a packet transmission unit for distributing a transmission packet from inside the communication device to a plurality of lines, and a packet reception unit for multiplexing packets received from the plurality of lines and transmitting the multiplexed packet to the inside of the communication device, The packet receiving unit of the communication device recognizes a congestion state inside the device from a packet storage counter that monitors the number of packets stored in the buffer memory that stores received packets, and compares the value of the packet storage counter with the buffer memory capacity. It has a local station congestion state notifying means for notifying this to a packet transmitting unit, and the packet transmitting unit of each of the communication devices, The congestion notification area includes a congestion state specifying unit that explicitly indicates the congestion state of the packet receiving unit. A communication station that recognizes a congestion state of the communication device for each line, and notifies a packet transmitting unit of the result of the recognition; and the packet transmitting unit further includes: According to the packet congestion notification of the device, to which line the packet to be transmitted should be output, or a selection means for selecting whether to notify a signal regulating the transmission to the buffer memory control unit inside the device, Each communication device, when the other communication device is congested,
Has a packet load balancing control unit that makes note of the output of the packet to the packet transmission unit, the operation in the packet load balancing control unit, said packet
Packet that is performed autonomously every time a packet is transmitted and received
Communication system. 2. As a communication path between communication devices, the communication device has a communication device interface such that communication devices are connected by a plurality of lines, and communication between the communication devices is guaranteed regardless of which line is used. The packet communication system used in a packet communication system having a packet transmission unit for distributing a transmission packet from inside the communication device to a plurality of lines, and a packet reception unit for multiplexing packets received from the plurality of lines and transmitting the multiplexed packet to the inside of the communication device. A communication device, wherein the packet receiving unit of each communication device monitors a number of packets stored in a buffer memory for storing received packets, and a packet storage counter based on a comparison between the value of the packet storage counter and the buffer memory capacity. A self-congestion state notifying unit for recognizing an internal congestion state and notifying the packet transmission unit of the internal congestion state; The packet transmitting unit has a congestion state specifying unit that explicitly indicates a congestion state of the packet receiving unit in a congestion notification area provided in the packet, and the packet receiving unit is defined on the received packet. The packet transmission unit further includes a counterpart station congestion state notifying unit that recognizes a congestion state of the communication apparatus on the other side for each line by looking at the congestion notification area, and notifies a packet transmission unit of the result. Selecting means for selecting a line to which a packet to be transmitted should be output or a signal for restricting transmission to be notified to a buffer memory control unit in the device in accordance with a packet congestion notification of the other communication device from the communication unit In addition, each of the communication devices, when the other communication device is congested,
Has a packet load balancing control unit that makes note of the output of the packet to the packet transmission unit, the operation in the packet load balancing control unit, said packet
Communication that is performed autonomously for each transmission and reception of data
apparatus.