JPH06103891B2 - Routing method for packet switching network - Google Patents

Description

TECHNICAL FIELD The present invention relates to a routing method in a packet switching network composed of a terminal accommodating exchange accommodating terminals and a transit exchange.

[Conventional technology]

In the case of the pocket exchange network, when the transit exchange is congested, it is necessary to have a means for controlling the traffic to the transit exchange. In the conventional packet switching network, since the packet transfer method in the network adopts the datagram method, the relay path is not fixed for each packet. It was not possible to determine whether or not the packet passed through the transit switch, and it was not possible to selectively restrict the input of only the packets that passed through the specific relay route.

[Problems to be Solved by the Invention]

For this reason, conventionally, when the transit exchange is congested, in order to regulate the inflow of packets to the transit exchange, in the adjacent exchange, by detouring the transit packet to another non-congested transit exchange, it is possible to take over. Since the method of reducing the load on the congestion transit exchange has been adopted, there is a problem in some cases that the transit exchange at the detour destination is congested and there is a high risk that the congestion will spread.

SUMMARY OF THE INVENTION An object of the present invention is to provide a routing method capable of performing congestion control capable of selectively restricting only packets passing through a congested relay route in order to solve the above problems.

[Means for Solving the Problems]

In the present invention, in order to solve the above-mentioned problems, the packet switching network is regarded as an area and divided into one or a plurality of areas. In each area, a plurality of relay exchanges are placed from the viewpoint of reliability, and all terminals in the area are arranged. While connecting to the accommodation exchange,
Each transit exchange has a network configuration in which it is connected to all other transit exchanges belonging to different areas.

In addition, for communication corresponding to a specific logical channel between the originating and terminating terminals, the same relay path, that is, the same trunk exchange and trunk line should be used fixedly in both directions of transmission and reception during the data transfer phase. , Select relay routes at the originating and terminating exchanges and transit exchanges.

Further, when a failure occurs in the relay route, the relay exchange notifies the originating and destination exchanges of the fault information, so that the communication of the same call is bypassed to another normal relay route by synchronizing with the originating and destination exchanges. The most important feature is to ensure that the relay paths in both the transmitting and receiving directions are the same, including when there is a failure.

[Action]

 The means for solving the problem works as follows.

When a communication call occurs and a packet is transferred from the source terminal to the destination terminal and the transit exchange on the transit route becomes congested, the transit switch congests the transit route to the originating exchange. By notifying that the status is in the state together with the identification information of the congested relay route, it becomes possible to selectively restrict only the input packet from the terminal which uses the relay route in the notified originating and terminating exchanges.

〔Example〕

FIG. 3 is an explanatory diagram showing a configuration example of a packet switching network to which the present invention is applied. In the figure, 1 and 2 are each area when the packet switching network is regarded as an area and divided into a plurality of small areas PA, PAi (i = 1, 2) is the number of each area PA, and 3 to 6 are relays Exchanges TS, TSij (i = 0,1, j = 0,1)
Is the transit switch TS in the number PAi area, j is the transit switch T
Transit exchange TS number in area PA given to S,
7 and 8 are terminal accommodating exchanges LS and 9 within the area of number PA0.
Is a terminal accommodating exchange LS in the area of number PA1, terminals 10 to 13
Indicates terminals accommodated in the terminal accommodating exchanges LS7-9.

Further, each relay exchange TS is connected to all relay exchanges TS of different areas PA by inter-station lines, each terminal accommodating exchange LS is connected to all relay exchanges TS of the area PA by inter-station lines, and each terminal is The line is connected to the terminal accommodating exchange LS accommodating the terminal.

FIG. 1 and FIG. 2 show the originating and terminating exchange LS when implementing the present invention.
FIG. 5 is an explanatory diagram showing an example of correspondence between a relay route connecting a relay exchange TS and a logical relay route identification number. In the figure, 20 is an area PA, 21 is a repeater exchange TS in each area, 22
Indicates the identification number of the relay route.

FIG. 4 is an explanatory diagram showing a detour method when a relay route fails. In the figure, 30 and 31 are terminal accommodation exchanges L
S, 32, and 33 are relay exchanges TS, 34 and 35 are relay route failure notifications from the TS to the LS, and 36 to 38 are detour destination cases when the relay route fails.

Here, a case where the repeater exchange TS in the area PA is two units will be described as an example.

Hereinafter, description will be given using these figures. The case where the relay route identification number is assigned in the range of 0 to 63 is shown.

First, regarding the relay route between the originating and terminating exchanges accommodated in different area PAs, if i <j as shown in FIG. 1 depending on the magnitude relationship between the own PA number i and the partner PA number j in advance (first In the figure (a)), for the relay route connecting TSi0 of PAi and TSj0 of PAj, 0 to 15 are identified as identification numbers, and similarly, TSi0 and
16 to 31 as an identification number for the relay path connecting TSj1
32 to 47 as an identification number for the relay route connecting TSi1 and TSj0, and for the relay route connecting TSi1 and TSj1 as
Be sure to assign 48 to 63 as the identification number.

If i> j, PAi in FIG.
0 to 15 as the identification number for the relay route connecting TSi0 and TSj0 of PAj, and similarly, 32 to 47 as the identification number for the relay route connecting TSi0 and TSj1 and connecting TSi1 and TSj0. For the relay route, use 16-31 as the identification number and TSi1
48-63 as the identification number for the relay route connecting TSj1
To be assigned.

As a result, if the calling party's PA number is larger than the calling party's PA number, on the receiving side, the calling party's PA number will be smaller than the calling party's PA number.Therefore, the crossed relay route connecting TSi0 and TSj0 Corresponding to the above, it is possible to make the relay route connecting the originating TS and the terminating TS corresponding to the same identification number the same for both transfer directions of the originating and terminating LS.

The relay route between the originating and terminating exchanges accommodated in the same area PA is i = j (Fig. 1 (b)),
In order to select the same TS from both the originating and terminating LS, the relay route identification number is 0 for TSi0 (= TSj0).
31 to 32, and 32 to 63 are assigned to TSi1 (= TSj1).

Figure 2 shows the case where a pure relay TS is inserted in the middle, and in this case as well, the allocation of the identification number to the relay route connecting the TS of PAi and the TS of PAj is exactly the same as in the case of Figure 1. Can be thought of. In this case, the relay route is relay
Which of the TSs is used has nothing to do with the relay route itself connecting the originating and terminating TSs.

Next, in FIG. 3, a case where the terminal 10 of the terminal accommodating exchange LS7 and the terminal 13 of the LS9 which are accommodated in different areas PA communicate with each other will be described as an example.

When a packet is received from the terminal 10, the LS7 indexes the link memory based on the terminal accommodation position and the logical channel number in the packet, and the unit number of the LS9 in which the destination terminal is accommodated and the area in which the LS9 is accommodated. Ask for a PA number.

After that, the own PA number i and the partner PA number j are compared, and according to the magnitude relation, the selection is made based on the random number generated from the logical channel information according to the correspondence relation between the identification number and the relay route shown above. Select the arrival / departure TS from the identification number.

Next, in FIG. 3, a case where the terminal 10 of the terminal accommodating exchange LS7 and the terminal 12 of the LS8 which are accommodated in the same area PA communicate with each other will be described as an example.

When a packet is received from the terminal 10, the LS7 searches the link memory based on the accommodation position of the terminal and the logical channel number in the packet, and the unit number of the LS8 in which the destination terminal is accommodated and the area in which the LS8 is accommodated. Ask for a PA number.

After that, the own PA number i compares the other party's PA number j, and the other party's PA number j
Since the number is equal to its own PA number, according to the correspondence relationship between the identification number and the relay route shown above, from the identification number selected based on the random number or the like generated from the logical channel information,
Select the same TS.

Next, referring to FIG. 4, a detour method when a failure occurs in the relay route will be described. For example, if a failure occurs in the relay route between the originating and terminating TSs 32 and 33,
At 33, a failure is detected, and the identification number corresponding to the failed relay route is notified to each of the originating LS30 and the terminating LS31. Upon receipt of the failure notification 34, the originating LS 30 evenly selects the identification numbers of all the remaining relay routes except the relay route in the failure state,
Make detours to distribute the load. Specifically, in the case of bypassing the destination TS33 as in 36, in the case of bypassing the originating TS32 as in 37, and in the case of bypassing the destination TS32, 33 as in 38.
There is a street. Similarly, the destination LS31 that has received the failure notification 35 is also detoured, and the same identification number is selected by the originating and destination LS so that the relay routes after the detour for the same call become equal.

〔The invention's effect〕

As described above, according to the present invention, when a transit exchange is congested, only packets passing through the exchange can be selectively identified and the input of packets to the congestion transit exchange can be restricted. Further, since the uplink and downlink of the call pass through the same relay route, there is an advantage that the originating and terminating exchanges can be synchronously regulated for each call, and excessive regulation can be prevented.

[Brief description of drawings]

FIG. 1 and FIG. 2 are explanatory views showing examples of correspondence between a relay route connecting the originating and terminating exchange LS and the transit exchange TS and a logical route identification number in carrying out the present invention, and FIG. FIG. 4 is an explanatory diagram showing a configuration example of a packet switching network to be implemented, and FIG. 4 is an explanatory diagram showing a detouring method when a relay route fails. Explanation of reference numerals 1, 2 ... transit switch accommodation area in packet switching network, 3 to 6 ... transit exchange, 7 to 9 ... terminal accommodating exchange, 10 to 13 ... terminal, 20 ... transit exchange accommodating area, twenty one
…… Relay switch, 22 …… Relay route identification number, 30,31…
… Terminal accommodating exchange, 32,33 …… Transit exchange, 34,35 …… Notification of relay route failure, 36 ～ 38 …… Detour destination when relay route fails.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichi Mukai 1-1-6 Uchiyuki-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (56) Reference JP-A-61-116642 (JP, A) JP Flat 1-98344 (JP, A)

Claims (1)

[Claims] 1. When performing communication for each specific logical channel between a given arbitrary terminal and another terminal in a packet switching network composed of a terminal accommodating exchange accommodating terminals and a transit exchange, A common identification number is assigned in advance to both the transmitting and receiving directions for the relay path consisting of the relay exchange connecting the exchanges accommodating the originating and terminating terminals, and the same originating and terminating logic is used in communication between specific logical channels between the originating and terminating terminals. For packets sent from any terminal between channels, select the identification number corresponding to the same relay route connecting the originating and terminating exchanges, and also when the relay route fails, Notify the route identification number, bypass the faulty relay route in the originating switch, and select the same normal relay route in both transmitting and receiving directions as in normal route selection. By this, packets sent from either terminal will be transferred to the other terminal via the same relay path, that is, the same repeater exchange and relay line, not only in normal times but also when making a detour due to a failure in the relay path. By doing so, it is possible to selectively restrict only the communication between the specific logical channels passing through the corresponding relay route with respect to the congestion of the specific relay route.