JPH022761A - Congestion control system - Google Patents

Abstract

PURPOSE:To prevent a call to a exchange in which congestion is generated from issuing by sending a test packet to an opposite packet exchange, and monitoring a congestion state based on difference between a delivery time and an arrival time by receiving a returned test packet. CONSTITUTION:The packet exchange (PS1-PS5) are started up periodically, and send the test packets from test packet modules A, and receive the packets returned from the test packet return module C of the opposite exchange. And a congestion decision module B takes the difference between the delivery time and the arrival time between the test pattern, and compares it with a prescribed reference value, then, decides the congestion state of a targeted packet exchange. In such a way, when the congestion is generated in the PS3 at the time of performing communication from a terminal TTY1 to a TTY2, the PS2 sets a route via the PS4. Therefore, it is possible to prevent the call to the exchange in which the congestion is generated from issuing.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a method of controlling the number of packet switches in a switching network, and in particular, congestion control in which a test packet is sent out to monitor the number of other packet switches. Regarding the method.

[Conventional technology]

Conventionally, in this type of congestion control method, each packet switch constantly monitors the usage rate of its own processor, and when it detects congestion on its own switch, it restricts calls from connected packet switches. The exchange is controlling the detour.

[Problem to be solved by the invention]

In the conventional congestion control method described above, each packet switch constantly monitors the usage rate of its own processor, and when it becomes busy, it controls the congestion by restricting calls from other switches. Therefore, the exchange that originates the call cannot recognize which route to send the call to to avoid congestion. Therefore, if a certain first selection route is a connection to a congested exchange, once a call is made to the congested exchange and the call is recognized as being restricted and cannot be connected, the user must search for another route. There must be.

[Means to solve the problem]

The congestion control method of the present invention transmits the test packets from a first packet switch having means for periodically transmitting test packets containing a transmission time to a second packet switch having means for returning the test packets as they are. sending out,
The first packet switch that receives the returned test packet has means for calculating the difference between the sending time and the arrival time and determining that the packet is too thick if it exceeds a predetermined reference value. The configuration is such that calls to the second packet switch are detoured.

〔Example〕

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

FIG. 1 is a configuration diagram of a packet network to which an embodiment of the congestion control method of the present invention is applied. Psi to PS5 are packet switching devices that constitute a packet network, respectively. TTYI
, TTY2 each indicate a terminal, packet switch PS
1 to PS5 are a test packet sending module A that is activated periodically and sends out test packets, a congestion determination module B that uses the returned packets to determine whether there is a problem with the opposite packet switch, and a test packet return module that returns test packets as they are. Each module has a module C.

Figure 2 shows the test packet sending module A, vergence determination module B, and test packet return module C shown in Figure 1.
FIG. The test packet sending module A is activated periodically and constantly sends test packets with input sending times to the target packet switch. The test packet return module C in the target packet switch returns the test packet as it is to the sending packet switch, and in the sending packet switch that receives the returned test packet, the congestion judgment module B checks the sending time and arrival time (reception time) in the test packet. time) and determines whether or not the target packet switch is in transit based on a predetermined reference value.

Referring to FIGS. 1 and 2, communication is performed from terminal TTY 1 to terminal TTY 2, and packet switch P
It is assumed that congestion occurs in S3.

Moreover, the packet switch PS2 is
The first selection route to No. 5 is via the packet switch PS3, and the second selection route is via the packet switch PS4. In this case, a call originating from terminal TTY1 is passed through packet switch PS1 to packet switch fiPs2. In the packet switch PS2, the packet switch PS3 . If a test packet is periodically sent to PS4 and a congestion check is performed, and if the packet switch PS3 is recognized as being short-circuited, then the packet switch PS3 is bypassed and the packet switch P
A route via S4 is set, and from terminal TTYI to terminal T
A call to TY2 will be set up.

〔Effect of the invention〕

As explained above, according to the present invention, by monitoring the congestion of the destination packet switch, it is possible to prevent a call from being made to a destination switch.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing one embodiment of the present invention. PS1 to PS5...Packet switch, A...
...Test packet sending module, B...Congestion determination module, C...Test packet return module, TTYl, TTY2...Terminal. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] Sending the test packet to a second packet switch having means for sending back the test packet as it is from the first packet switch having means for periodically sending the test packet containing the sending time, and returning the test packet. The first packet switch that receives the packet has a means for calculating the difference between the sending time and the arrival time and determining that there is congestion when a predetermined reference value is exceeded, and when it is determined that there is congestion, the packet is sent to the second packet switch. A congestion control method characterized by diverting calls.