JPH03112239A - Packet transmission method - Google Patents

Abstract

PURPOSE:To prevent communication interrupted for a long time when a fault occurs on a relay line and to simplify a communication continuation processing by performing the re-connection of a logical route simultaneously only between stations in which faults are detected, and using the similar logical route as the one used before the fault occurs as another logical route. CONSTITUTION:When the fault occurs on the relay line c(6-c) between packet switching stations A and C, the station A generates a re-link setting packet when detecting the fault. Next, the station A transmits the re-link setting packet to a station B after selecting the relay line d(6-d), and also, updates a table 11 as a table 12 temporarily. The station B relays the logical route number p of an input side relay line d to the station C conforming to the logical route number q of an output side relay line l with the table 12 by the same procedure as at the start of ordinary communication. The re-link setting packet arriving at the station C becomes a trigger to copy output side information in the number q in a table 13 to the position of the number q of an input side relay line e. Thereby, it is possible to recover the interruption of communication due to the fault on the relay line with a simple processing without extending for a long time.

Description

[Detailed Description of the Invention] (1) [Industrial Application Field] Particularly, the invention of Party B is directed to a system for transmitting back-cuts to terminals in a bucket-switching network, at the time of starting communication between one terminal.

The present invention relates to a packet transmission method in which packets are transmitted through a logical communication path configured by fixedly connecting logical paths set between two relay stations and a receiving station.

[Conventional technology]

Figure 4 shows 9 For example, "IE Transactions on Communications, VOL.

COM-27, No. 8, August 1979,
115g-=1160 pages, Paper title: Comparative Discussion of Circuits-■S, Packet Switched Voice" (IEE TRANSACTION
S ON COMMUNICATIONS, V
OL.

COM-27, No. 8, Person UGUST
1979. P 1153-11601.

Paper name: compa'rative Discussi
on of C1rcuitVS, Packet-
3witched VoiceJ) is a diagram showing a conventional back-to-back transmission method in a packet switching center of this type, as shown in 3witched VoiceJ).
) is a packet switching center, (5-]) and (5-2) are terminals connected to stations A and (2) and station E, respectively, and (6-a) is a terminal (51
) and the terminal line connecting station A (4-A), (e-b
) is the terminal line connecting terminal (5-2) and station E (4-E), and (8-c) to (8-g) are the terminal lines for each exchange (
4-Mon ~ (Relay line connecting between 4-E1, (8) is station A
A table that associates the input logical communication path number on terminal line a of a packet input from terminal line a (6-a) with the output logical communication path number on trunk line C or d, which is the outgoing route for other stations. , (00) is a table that associates the input logical communication path number in the trunk line C with the output line and the logical communication path therein at station C, which is also a packet switching center (4-C) as in 911, This is a table that associates the input logical communication path number of the trunk line f with the output line and the logical communication path number therein in station E, which is an exchange (4-E).

Next, the operation will be explained. From the terminal (5-1) to the terminal (
When a communication request for 5-2) is sent to station A using logical channel number l in table (8), station A transmits the outgoing relay to station E that accommodates terminal (5-2). Select the line C and the logical communication channel number m therein, and make the correspondence according to the table]8)(3). The communication request is sent to station C.

Station C selects the outgoing trunk line f to station E and the logical communication path number n therein from table (9), and selects the logical communication path number m of the incoming trunk line C and the logic of the outgoing trunk line f. communication channel number n. The communication request is further sent to station E, and similarly, the logical communication path number n of the incoming trunk line f and the logical communication path number 0 of the outgoing terminal line are associated using the table α0). Next, a response is issued from the terminal (5-2), and the above correspondence is determined by following the two opposite routes, and the logical communication path between the terminal (5-1) and the terminal (5-2) is determined. From now on, data transmission/reception (3) will be performed.

During communication using such a logical communication path, for example, if a failure occurs in the trunk line C between station A and station C, the two subordinates and station C each follow the logical communication path and erase it. , the logical communication path is set up again from station A. At this time, station 2 A
Since trunk line C has a fault -C, a logical communication path is set by selecting trunk line d to two stations B, and station B also connects trunk line e to station B.
The station C selects the trunk line f as the logical communication path, and then the station C selects the trunk line f as before the failure, and the logical communication path is re-established.

(4) [Problem to be solved by the invention] Since the conventional packet transmission method is configured as described above, when a failure occurs in the packet switching network, the terminal (5-
1), (5-2)
It is necessary to reset the logical communication path between -A) and (4-E). Therefore, all information on the logical communication channel that had been used up until now was deleted, and a new station (4
Since the logical communication path resetting operation is performed from -A) to the other end unaccommodated station (4-E), there are problems such as a longer interruption time for one communication.

This invention was made to solve the above-mentioned problem, and it simultaneously reconnects the logical paths between the fault detection stations and reconnects the other logical paths as before the fault occurred. To provide a packet transmission method which prevents a long communication interruption time when a failure occurs in a packet switching network due to a communication device being used, and which allows communication continuation processing to be performed easily without being complicated.

[Means to solve the problem]

The packet transmission method according to the invention of Party B is as follows: (5) The stations on both sides of the trunk line that have detected a failure must simultaneously re-determine the link setting bucket 1- by bypassing the failed relay line; The table is tentatively updated as the information is sent to the station, and the detour relay station performs normal association without being aware of relinking and is relayed.

Furthermore, the partner failure detection station updates the table so that it corresponds to the outgoing logical route before the failure.

[For production]

The packet transmission method in Party B's invention is such that when the relay line becomes unusable due to a failure in the relay line.

Only between the stations at both ends where a fault in the trunk line was detected, the logical route is reconnected by the 2-relink setting packet, and for the other logical routes, the same logical H path as before the fault was used, and 2 communications are carried out. To continue without broadcasting for a long time.

〔Example〕

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

FIG. 1 is a format diagram of the relink setting bucket 1 in this invention. In FIG. 2, (1) is a packet identification unit (21t or This is a relay header section for relaying within a network similar to a normal packet. Figure 2 is an example of the relay header section. In Figure 2, (2-1) is a destination station display section, (2-2) is the local station display section. Fig. 3 is a diagram for explaining the packet transmission method according to the present invention, in which the correspondence tables (1) and (13) have been changed, and the correspondence table (one has been added). The rest is the same as the conventional example shown in FIG. 4, so the explanation will be omitted.

Next, the operation of the above embodiment will be explained. In FIG. 3, consider the case where, for example, trunk line c (6-c) between stations A and C becomes a failure. Station A detects the faulty trunk line.

It is detected in both stations C, and the relink setting packet shown in FIG. 1 is sent to stations C and A, respectively, but since they are exactly the same, we will explain the operation from station A in FIG. 3. conduct. When station A detects a failure in the trunk line, it generates a link setting packet). In the relay header section of the generated packet, information 2 of station C is added to the destination station display section in FIG. 2, and information about station A is attached to the own station display section.

(7) Station A then selects trunk line d (6-d) and sends this re-link setting bucket 1- to station B, and also changes table (8) to table (11). Temporarily update.

Table (11>) maps the logical route number -p in table (8) that corresponds to the logical route number n of the outgoing trunk line C to the logical route number p of the outgoing trunk line d. 2 station B, without thinking that middle line 1a line C is a failure, uses the same procedure as when starting normal communication to find the logical route number p of ingress trunk line d in the table (from 1). It is associated with the logical route signal q of the outgoing trunk line e and relayed to station C. The re-link setting packet I that arrived at station C as shown in
- Ilf, at station C, copy the outgoing information at the logical route number m of the incoming trunk line C in table (9) to the logical route number q position of the incoming trunk line e, and Become.

Furthermore, when the re-link setting bucket 1- from station C to station A arrives at station A, the table (11) tentatively updated at station A is made official, and 1, in which a logical communication path to (5-2) is formed, and similarly, a logical postscript path (8) from terminal (5-2) to terminal (5-1)-\ is also set at approximately the same time.

〔Effect of the invention〕

As shown in Part 2, according to the invention of Party B, a relink setup packet is simultaneously sent between the fault detection stations to the other faulty station, only the logical route that has been set up as a fault relay is detoured, and a new link setup packet is created. By connecting logical routes and using as much as possible the logical route that was established before the failure, and by sending relink setting packets to each other, it is possible to create a logical postscript path between failure detection stations without receiving a response. Because you can replace it.

This has the effect of being able to restore communication relays due to trunk line failures without a long delay.

[Brief explanation of drawings]

FIG. 1 is a diagram of the relink setting packet format according to an embodiment of the present invention, FIG. 2 is a diagram for explaining the relay header section in FIG. 1, and FIG. 3 is a diagram for explaining the details of the invention of B and FIG. 4 are diagrams for explaining a conventional example. In the figure, (1) is the packet identification section, (4-A) ~
(4-E'1 is a packet switching center, (5-11, (5-
2) is a terminal, (6-c) to (9) (6-g) are trunk lines. (8) to (13) are tables. In addition. In the figure. The same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] Packet transmission between a transmitting terminal and a receiving terminal in a packet switching network is performed by a transmitting station consisting of a packet switching center that accommodates the transmitting terminal and transmitting packets, a relay station consisting of a packet switching center, and a receiving side. In a packet transmission method, the packet transmission method is carried out through a logical communication path configured by fixedly connecting a logical path set between each receiving station consisting of a packet switching center accommodating the terminal,
The failure detection stations at both ends of the relay line that have detected a trunk line that has become unable to communicate due to a line failure issue relink setting packets to the other failure detection station at the same time, reconnecting the logical route only between the two stations. A packet transmission method characterized in that the other logical routes are the same logical routes as before the failure occurred.