JPS6384227A - Congenstion control system for packet network - Google Patents

Abstract

PURPOSE:To minimize the effect due to traffic restriction by supervising traffic state and using an information bit when the traffic reaches a prescribed level or over so as to apply stepwise traffic restriction. CONSTITUTION:A TYPE bit is added to a packet signal as an information bit representing whether it is a connection set packet or a connectionless packet. A traffic supervisory circuit 15 in terminal interface circuits 1-3 supervises a traffic state on a bus 100 and in detecting a traffic of a prescribed level or over, it is informed to a TYPE bit detection circuit 12. The circuit 12 inhibits the write of the connectionless packet signal into a transmission buffer 11 among packet signals from the terminal equipment. Thus, the input of the connectionless type packet to the packet network is restricted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to traffic regulation control during times of congestion in a packet network, and particularly relates to a connection establishment type packet that performs communication after establishing a connection between communication devices. This invention relates to a congestion control method for a packet network that accommodates communication and connectionless packet communication that does not set up a connection.

[Prior art and its problems]

-i, when the network receives traffic exceeding its processing capacity, it restricts input to eliminate the overload condition. The same applies to packet networks, but if such regulations are enforced uniformly, the following problems will arise. Packet communication includes connection-setting type communication in which communication is performed after a connection is established between communication devices, and connection-less type communication in which communication is not established. In the former, flow control is normally performed based on land control. That is, until a response signal is returned from the receiving side communication device, the sending side communication device holds an outstanding number of packets in preparation for retransmission. If traffic regulation is uniformly applied to such communications, packets may accumulate within the transmitting device, which may cause new congestion.

An object of the present invention is to perform traffic regulation in stages to further reduce the influence of this regulation.

[Means for solving problems]

The present invention is a congestion control method for a packet network that accommodates connection-setting type packet communication in which communication is performed after setting up a connection between communication devices, and connection-less type packet communication in which a connection is not set up. An information bit indicating whether the packet is a connectionless packet is added to the packet signal, and the packet network monitors the traffic status within the network. If the traffic exceeds a certain level, the packet network uses the information bit to determine if the packet It is characterized by performing traffic control in advance.

[Effect]

A packet signal has an identification information bit attached to it indicating whether it is a connection setup type packet or a connectionless type packet, and when a congestion state occurs as a result of monitoring the traffic status, the latter is identified using the information bit. Traffic control for types of traffic is first performed. Traffic regulation for such preceding connectionless packets prevents new causes of congestion, such as the accumulation of connection setup packets in the transmitting device, and prevents packet communication of both types. Even in a packet network that accommodates packet networks, it is possible to perform traffic regulation control without the inconveniences that would occur if traffic regulation was performed strictly.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

A first embodiment of the present invention will be described using FIGS. 1 and 2. FIG. 1 shows a packet network in which terminals 19.29.39 are connected to a bus 100 via terminal interface circuits 1.2.3. The terminal interface circuit 1 includes a transmission buffer 11 that receives and transmits a packet signal from a terminal 19, and a TYPE bit added to the packet signal as an information bit indicating whether it is a connection setting type packet or a connectionless type packet as described later. a detection circuit 12, a reception buffer 13 that receives the packet signal via the bus 100 and supplies it to the terminal 19;
An address filter 14 that monitors the destination address of a packet signal, a traffic monitoring circuit 15, and a control circuit 16.
It consists of The monitoring circuit 15 is a circuit that monitors the traffic state on the bus 100.

The terminal interface circuits 2 and 3 also have the same configuration as the terminal interface circuit 1.

FIG. 2 shows the frame structure of a packet signal used in this embodiment, which is delimited by a start delimiter SD and an end delimiter ED, and includes a TYPE bit indicating whether the packet is a connection setting type or a connectionless type as header information.
It has a destination address, a source address DA, SA, a control I field C used for flow control, etc., as well as an information field INFO and a frame check sequence FC.
It is composed of 3. In this way, the TYPE bit is added to the packet signal as an information bit indicating whether it is a connection setting type packet or a connectionless type packet.

Each terminal interface circuit 1 to 3 connects the bus 100 when a packet signal from the terminal is received by the transmission buffer 11.
The above state is monitored, and if it is idle, the transmission buffer 11 is activated and transmission is performed. At this time, if a collision occurs on the bus 100, transmission control is performed again. - On the other hand, in reception,
The address filter 14 is the destination address D of the packet signal.
Monitor A, and if it is addressed to you, receive it. The packet signal received by the reception buffer 13 is subjected to an error check based on the frame check sequence FC8, and if the reception is normal, it is supplied to the terminal.The traffic monitoring circuit 1
5 monitors the traffic state on the bus 100, and if traffic exceeding a certain level is detected, it notifies the TYPE bit detection circuit 12 of this fact. This traffic state can be detected, for example, based on the number of collisions within a certain period of time. In a traffic congestion state, the detection circuit 12 prohibits writing of a connectionless type packet signal among packet signals from a terminal into the transmission buffer. This prohibition control is maintained until the monitoring circuit 15 detects that the traffic has fallen below a certain level and notifies the detection circuit 12. This control 2g restricts input of connectionless packet signals to the packet network. In this way, the packet network congestion control method of this embodiment is applicable to a packet network that accommodates connection-setting type packet communication in which communication is performed after setting up a connection between communication devices, and connection-less type packet communication in which a connection is not set up. , an information bit indicating whether the packet is a connection setup type packet or a connectionless type packet is added to the packet signal, and the packet network monitors the traffic status within the network, and if the traffic exceeds a certain level, the information bit indicates that the packet is connectionless. Input into the packet network of packet signals indicating that the type is

In this way, when controlling traffic regulation during congestion in such a packet network, instead of restricting traffic strictly, when traffic congestion occurs in the packet network, traffic regulation for connectionless packets is carried out in advance. In this embodiment, input into the packet network is restricted as traffic restriction. In this case, connection setup type packet signals are communicated without being subject to this regulatory control, so the retention time of packet signals held in terminals for flow control between terminals is regulated by connectionless communication packet signals. It will be shorter by the amount of time.

FIG. 3 shows a second embodiment of the invention. In the first embodiment, each terminal interface circuit monitors traffic in a distributed manner, whereas in this embodiment, this function is performed centrally.

That is, in the case of this embodiment, each of the terminal interface circuits 1 to 3 has a transmission buffer 11 . Detection circuit 12. Receive buffer 13. Address filter 14.
A monitoring circuit 101 and an arbiter circuit 102 are provided for the terminal interface circuits 1 to 3, including the control circuit 16. In the arbiter circuit 102,
Signals S1-1n S2-1゜53-1 are supplied from the control circuits 16 of each terminal interface circuit 1 to 3 as transmission request signals, and to each control circuit 16,
Signal S I-2) S R-2+ from the arbiter circuit 102
32-2 is selectively supplied as a permission signal.

In this embodiment, the arbiter circuit 102 uses the signal S
A transmission request signal from the control circuit 16 of each terminal interface circuit 1 to 3 such as I-1 is input, one terminal interface circuit to which transmission is to be permitted is specified, and the signal S, for example, is inputted.
-2 is supplied as a permission signal.

A traffic monitoring circuit 101 monitors transmission requests sent to the arbiter circuit 102 from these terminal interfaces, counts the duration of a state in which at least one transmission request is supplied, and detects traffic if this time exceeds a certain value. is determined to be congested, and instructs the detection circuits 12 of all terminal interface circuits 1 to 3 to start input restriction similar to the first embodiment.

FIG. 4 is a diagram showing the configuration of a terminal interface circuit used in the third embodiment of the present invention. In the first and second embodiments, only the input to the transmission buffer 11 was restricted, but in this embodiment, the traffic that is input to the transmission buffer 11 is restricted. It realizes control. In addition to the configuration shown in FIG. 1, the terminal interface circuit has a management table 17 indicating the storage status of packet signals in the transmission buffer 11. This table 17 includes the storage start address and length information of each packet signal waiting to be transmitted, as well as the detection circuit 12.
The TYPE bit of the packet signal detected in is written as management information. The control circuit 16 is
When traffic regulation is instructed by the monitoring circuit 15, the table 17 is referred to and the management information of the packet signal whose TYPE bit indicates that it is a connectionless type is deleted from the table 17. With this control, the transmit buffer l
Connectionless packet signals that are waiting to be transmitted and remain within l are discarded.

In this way, in the packet network congestion control method using the terminal interface circuit configured as shown in FIG.
In a packet network that accommodates connection setup type packet communication in which communication is performed after a connection is established between communication devices, and connectionless type packet communication in which a connection is not established, an information bit indicating whether the packet is a connection setup type packet or a connectionless type packet is used. In addition to packet signals, the packet network monitors the traffic status within the network, and if the traffic exceeds a certain level, the information bits of the connectionless packet signals staying within the packet network are Discard packet signals indicating that

The traffic regulation control based on the congestion state of the bus in the packet network has been described above, and the control for overflow of the reception buffer of each terminal interface circuit will be described below. In this case, in each terminal interface circuit that performs control based on the destination information of the packet signal, that is, based on the route information, when the usage status of the reception buffer 13 exceeds a certain level, for example, the usage of the buffer is When the area exceeds a certain amount or when the frequency of overflow exceeds a certain number of times, the control circuit 16 instructs the control circuits of all other terminal interface circuits to start regulating transmission via the bus 100. . Now, suppose that, as shown in FIG. 1 or 3, there are terminal interface circuits 1, 2.3 connected to each terminal 19, 29, 39, and the received traffic increases in terminal interface circuit 2. . When the control circuit 16 of the terminal interface circuit 1 receives this transmission restriction instruction signal, it instructs the detection circuit 12 to determine the own destination address D of the transmission packet signal from the terminal 19.
The transmission buffer 11 where A indicates the terminal 29 and the TYPE bit of the packet indicates connectionless type.
Instructs to prohibit writing to.

This restriction restricts the input of connectionless packet signals to the terminal 29.

In such a case, in a packet network that accommodates connection-setting type packet communication in which communication is performed after setting up a connection between communication devices, and connection-less type packet communication in which a connection is not set up,
An information bit indicating whether the packet is a connection setup type packet or a connectionless type packet is added to the packet signal, and the packet network monitors the traffic status of each route within the network, and if the traffic on that route exceeds a certain level. , restricts the input into the packet network of packet signals whose destination address indicates the use of such a route and whose information bits indicate that it is connectionless. In this way, control during congestion in such a packet network may be performed.

In addition, using the configuration shown in FIG. 4, packets that accommodate connection setting type packet communication in which communication is performed after setting up a connection between communication devices and connectionless type packet communication in which no connection is set up as a congestion control method for a packet network. In the network, an information bit indicating whether the packet is a connection setup type packet or a connectionless type packet is added to the packet signal, and the packet network monitors the traffic status of each route in the network, and if the traffic on that route exceeds a certain level. In this case, it can be used as a control method to discard packet signals whose destination address indicates the use of this route and whose information bits indicate that they are connectionless, among the packet signals remaining in the packet network. good.

That is, by adding the destination address information of the transmission packet as management information to the management table 17 of the terminal interface circuit shown in FIG.

FIG. 5 shows a fourth embodiment of the present invention, and shows a first embodiment of the present invention.
．． The network shown in the embodiment 2.3 is used as a subsystem, and a packet network consisting of a plurality of these subsystems is shown.

This network consists of three subsystems 110, 210
310, each subsystem 110, 210
．． 310 is a control unit indicated by 111 or 211;
It has trunk buffer circuits shown at 112, 113, 212, 213, etc. This trunk buffer circuit 1
12.113, 212゜213 is for communication between subsystems, and has a reception buffer for receiving packet signals from other subsystems and a transmission buffer for buffering packet signals to other subsystems, For example, communication between subsystems 110, 210 occurs via trunk buffer circuits 112.212.

Each subsystem 110.210.310 also includes:
It has terminal interface circuits 1-3, 4-6 each connected to a bus 100, 200, each of which is connected to a terminal (not shown).

Assuming that the traffic on the bus 200 of the subsystem 210 is now congested, the control unit 211 instructs the terminal interface circuit 4.5.6 to restrict transmission, and also controls the control unit 111 of the subsystem 110 and the subsystem 310.
to the control unit. In the subsystem 110,
Based on this, 1. By the same method as shown in the third embodiment, input of connectionless packet signals from the terminal interface circuit to the transmission buffer (not shown) in the trunk buffer circuit 112 is prohibited. Alternatively, the connectionless packet signal in the transmission buffer is discarded. If congestion occurs in a receiving buffer (not shown) in the trunk buffer circuit 212 that receives a packet signal from the subsystem 110, the control unit 211 issues such an instruction only to the subsystem 110.

Note that communication between the control units of each subsystem 110, 210, and 310 may use the same communication network as the communication between terminal interface circuits, or may be performed via a communication network dedicated to control signals, such as a common line signal network. You may go. If traffic congestion occurs in the receive buffer of a certain terminal interface circuit in the subsystem 210, traffic regulation for connectionless packet signals addressed to that terminal interface circuit is applied to the transmit buffers and trunk buffer circuits of all terminal interface circuits. This is done for the receive buffer.

In addition, although the explanation has been given above as an example in which the traffic regulation control between the subsystems 110, 210, and 310 is performed in the trunk buffer circuit and control is not performed in each terminal interface circuit, the first. The second and third embodiments may be implemented in each terminal interface circuit in the same manner as in the third embodiment. That is, the control unit of each subsystem 110, 210, and 310 notifies each interface circuit of the details based on the traffic regulation control instruction from the control unit of the other subsystem. For example, if congestion occurs in the trunk buffer circuit of the subsystem 210 or in the bus 200, the control unit 111 of the subsystem 110 sends a connectionless packet signal addressed to the subsystem 210 to the terminal interface circuits 1, 2.3. order to restrict the transmission of If congestion occurs in the reception buffer of the terminal interface circuit 4, transmission of connectionless packet signals addressed to this terminal interface circuit is restricted.

In the former, control is performed by referring to the part indicating the subsystem of the destination address DA of the transmitted packet, and in the latter, control is performed by referring to the entire destination address DA.

[Effects of the Invention] As described above, according to the present invention, when performing traffic regulation control during congestion in a packet network that accommodates connection setup type packet communication and connectionless type packet communication, Since traffic regulation can be carried out in stages rather than by regulation, the following effects can be obtained.

(1) When traffic congestion occurs in the packet network, by prioritizing traffic regulation for connectionless packets, it is possible to improve the throughput for connection-setting packet signals, and it is possible to improve the throughput for connection-setting packet signals. The residence time of such packet signals within a terminal or within a network can be reduced.

(2) When local traffic congestion occurs in a packet network, traffic control can be performed by identifying connectionless packet signals that pass through such locations, minimizing the impact of traffic regulation. can be suppressed to

(3) Since it is possible to identify whether a packet signal is a connectionless type packet signal or a connection setting type packet signal simply by referring to the flag information in the header of the packet signal, traffic regulation control can be easily and quickly realized.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the invention, FIG. 2 is a diagram showing an example of the frame structure of a packet signal used in the invention, and FIG. 3 is a diagram showing a second embodiment of the invention. , FIG. 4 is a diagram showing an example of the configuration of a terminal interface circuit used in a third embodiment of the present invention, and FIG. 5 is a diagram showing a fourth embodiment of the present invention. 1 to 6...Terminal interface circuit 11...
...Transmission buffer 12...Detection circuit 13...Reception buffer 14...Address filter 15, lot...Monitoring circuit 16... ... Control circuit 17 ... Management table 19, 29.39 ... Terminal 100.200 ... Bus 102 ... Arbiter circuit 110.210.310 ... Sub System 111.
211...Control unit 112.113, 212.213...Trunk buffer circuit

Claims (5)

[Claims] (1) A congestion control method for a packet network that accommodates connection-setting type packet communication in which communication is performed after setting up a connection between communication devices, and connection-less type packet communication in which a connection is not set up; An information bit indicating whether the packet is a connectionless type packet is added to the packet signal, and the packet network monitors the traffic status within the network. If the traffic exceeds a certain level, the packet network uses the information bit to reduce the traffic to the connectionless type bucket. A congestion control method for a packet network characterized by performing control in advance. (2) In the congestion control method for a packet network according to claim 1, the traffic control regulates the input of a packet signal whose information bit indicates that it is a connectionless type into the packet network. A congestion control method for packet networks characterized by the following: (3) In the congestion control method for a packet network according to claim 1, the traffic control is based on information bits indicating that the information bits of the packet signals staying in the packet network are of a connectionless type. A congestion control method for a packet network, characterized in that it is performed by discarding packet signals that are present. (4) In the congestion control method for a packet network according to claim 1, monitoring of the traffic state is performed by monitoring the traffic state for each route in the network, and the traffic on such route is When a certain level is exceeded, traffic control is achieved by restricting the input into the packet network of packet signals whose destination address indicates the use of such a route and whose information bits indicate that it is connectionless. A congestion control method for packet networks characterized by: (5) In the congestion control method for a packet network as set forth in claim 1, monitoring of the traffic state is performed by monitoring the traffic state for each route in the network, and the traffic on such route is When the level exceeds a certain level, traffic control is applied to packets whose destination address indicates the use of this route and whose information bits indicate that they are connectionless, among the packet signals remaining in the packet network. A packet network congestion control method characterized by discarding signals.