JPS5932935B2 - Adjacent station congestion control method in packet-switched networks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a congestion control method for reducing packet relay processing of a station whose common resource usage rate reaches a certain rate or more determined by a packet network.

Conventionally, the regulation of relayed packets at packet switching centers was as follows:
A packet switching center whose common resource usage rate has reached a certain rate or more determined by the packet network notifies neighboring stations of the regulation of all packets, and also requests all packet switching centers accommodating data terminals to self-register. A method was adopted in which communication restrictions with station-accommodating terminals were notified and packet reception was restricted until the common resource usage rate fell below a certain value determined by the network.

However, with this method, packets whose destination is the packet switching center that has notified the restriction will be invalidly bypassed by the packet switching center that is adjacent to the packet switching center that has notified the restriction. No input restrictions (including input restrictions from data terminals) were possible for relay packets from each packet switching center that sent packets that were not intended for the destination station.

Due to this, there was a risk that the common resource bandwidth of a specific station would expand to neighboring stations one after another. The purpose of the present invention is to
It is an object of the present invention to provide a control method that eliminates the conventional drawbacks as described above, reduces invalid detour packets, and prevents common resource congestion from spreading to adjacent stations.

That is, in order to prevent invalid packets from being detoured and common resource congestion from spreading to adjacent stations due to full input restrictions in a packet switching network, the present invention sets levels for input restrictions from adjacent stations and Before full regulation is implemented, a packet switching center that detects that the common resource usage rate of a packet switching center has reached a certain value or more determined by the packet network will send an adjacent station congestion notification packet to all neighboring packet switching centers. By sending out packets other than those whose destination is the local station and diverting them to other exchanges at neighboring stations, restrictions on packets whose destination is the local station are reduced, invalid packets are less likely to be detoured, and specific packets are This prevents exchange congestion from spreading to the entire packet network.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an example of the configuration of a packet switching network. As shown in FIG. 1, the packet switching network 10 includes a plurality of switching stations such as packet switching stations 1, 2, 3, and 4, and interoffice trunk lines 20, 21, 22, and 22 connecting the respective packet switching stations.
Each packet switching station 1, 2, 3, 4 accommodates a data terminal 11, and each data terminal 11 communicates via the packet switching network. Each packet switching center 1 to 4 has a common resource usage rate measurement table 25 shown in FIG. 2a and an adjacent station congestion resource usage rate measurement value table 26 shown in FIG. and the adjacent station congestion limit value, and when the common resource usage rate is greater than the limit value, an adjacent station congestion notification packet shown in FIG. 3 is sent to all adjacent packet switching stations.

The state of adjacent station convergence control will be explained below using the configuration shown in FIG. 1 as an example.

In FIG. 1, when the common resource usage rate in the packet switching center 3 exceeds the restriction value shown in the adjacent station congestion resource usage rate restriction value table 26 shown in FIG.
The neighbor station congestion notification packet 30 shown in the figure is sent to the packet switching stations 1, 2, and 4 shown in FIG. Instruct 1, 2, 4.

In addition, in Fig. 3, 31 is the destination station number (DNOC).
, 32 indicates a transmitting station number (SNOC), and 33 indicates packet format identification information (PTYP), respectively. Each of the packet switching stations 1, 2, and 4 that has received the adjacent station congestion notification packet 30 uses the inter-relay station line selection table 4 shown in FIG.
0, adjacent station congestion light display table 60 shown in FIG. 6a, No. 6
It has an adjacent station number registration table 62 shown in FIG. It is displayed in the adjacent station convergence display (P) 61 of the display table 60.

When packet switching stations 1, 2, and 4 send a packet between other packet stations, they first select the inter-relay station line selection shown in FIG. 4 using the destination station number (DNOC) 53 of the packet 50 shown in FIG. The table 40 is indexed and the exchange center determination display (PI
) 44 to obtain the first inter-station route number (RUTl) 41 to be sent, and by indexing the adjacent station number registration table 62 shown in FIG. Identify whether the station is the target station or not, and if it is not the target station, display the adjacent station ring display table 6 shown in Figure 6a.
Check 0.

If the adjacent station congestion ring display (P) 61 is a light congestion display, obtain the second inter-office route number (RUT2) 42, and select the bucket sending inter-office route using the same procedure as the first route selection. Make a selection. If the adjacent station congestion ring indication 61 is not a congestion indication, the packet is detoured to that inter-office route number (RUT-). The data communication packet 50 shown in FIG. 5 includes a destination station number (DNOC) 51, a source station number (SNOC) 52,
Packet format identification information (PTYP) 53, communication message 54
Consists of etc. When the destination station of the processed packet is the packet switching center 3, the packet is sent to the first inter-office route number (RUTl) regardless of the presence or absence of the adjacent station congestion indicator (P) 61.

Although the above description has been made using the congestion of the packet switching center 3 as an example, congestion control can be performed in the packet switching centers 1, 2, and 4 in exactly the same manner.

As described above, according to the present invention, when the common resources of a packet switching center become congested, packets other than those whose destination station is the congested station are detoured to the adjacent station, thereby reducing the packet relay processing of the congested station. This makes it possible to process packets other than those whose destination is a ring station at a station other than the ring ring station, making it possible to distribute relay processing within the packet network and prevent congestion from a particular station from spreading to the entire network. This has the advantage of being preventable. It also has the advantage of being economical since no special equipment is required.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of a packet switching network, FIG. , Figure 3 is a diagram showing the format of an adjacent station congestion notification packet that notifies an adjacent packet switching center of congestion at a packet switching center, and Figure 4 is a diagram showing the format of an adjacent station congestion notification packet that notifies an adjacent packet switching center of congestion at a packet switching center. Figure 5 is a diagram showing an example of the configuration of a line selection table, Figure 5 is a diagram showing the format of a packet for data communication, Figure 6a is an adjacent station congestion ring display table, and Figure 6 b is an adjacent station number registration table showing adjacent station numbers. It is a figure showing an example of composition. 1, 2, 3, 4: Packet switching center, 10: Packet switching network, 11: Data terminal, 20, 21, 22, 23, 24
: Inter-station relay line, 25: Common resource usage rate measurement table, 26: Adjacent station congestion resource usage rate regulation value table,
30: Adjacent station congestion notification packet, 31, 51: Target station station number? DNOC), 32, 52: Source station number (SNOC)
), 33, 53: Packet format identification information (PTYP),
40: Inter-relay station line selection table, 41, 42, 43:
Interoffice route number (RUT), 44: Switching center determination display (PI
), 50: Data communication packet, 54: Communication message, 6
0: Adjacent station convergence ring display table, 61: Convergence ring display (P),
62: Adjacent station number registration table.

Claims (1)

[Claims] 1 In a packet switching network, when a packet switching station that makes up the network detects that the usage rate of common resources for switching processing at that station has reached a certain rate or more determined for the packet network, all adjacent packet switching stations The adjacent station that receives the adjacent station congestion signal transmits the adjacent station congestion signal, except for packets whose destination station is the exchange that sent the adjacent station congestion signal. An adjacent station congestion control method in a packet switching network characterized by detouring packets to a station other than the packet switching center.