JPH04311127A - Routing system for data exchange network - Google Patents

Abstract

PURPOSE:To obtain a data exchange network routing system capable of determining a by-pass route in consideration of traffic and shortening a route selection processing time. CONSTITUTION:The number of calls used in each repeating route is stored in each of plural repeating route calling frequency counters 7a to 7d, and when a certain repeating route is disabled due to the generation of fault or the like in one of repeating lines 2a to 2f or when the disabled route is enabled due to fault recovery or the like, the average number of calls in the repeating route at this point of time is calculated and calls are uniformly distributed to all usable repeating routes based upon the calculated value. Consequently the data exchange network routing system capable of uniformly distributing calls to normal repeating routes even at the time of generating a fault or recovering the fault, always setting up the numbers of calls in respective repeating routes in consideration of traffic, and by-passing a trouble or the like by an extremely simple method almost without requiring processing time for route selection.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing method in a fixed-route data exchange network in which the network is composed of data exchangers such as packet exchangers and asynchronous transfer mode (ATM) exchangers.

0002

[Prior Art] FIG. 4 shows, for example, patent application No. 257 of 1990.
57 is a block diagram showing a routing method in a conventional data exchange network shown in the specification and drawings of No. 57; FIG.

[0003] In the figure, 1a to 1d are packet switching devices serving as data switching devices, and 2a to 2e are relay lines interconnecting the packet switching devices 1a to 1d. 3a to 3d are the packet switches 1a to 1d.
4a to 4d are terminal devices accommodated in any of the packet switches 1a and 1d, for example, and 4a to 4d are each terminal device 3a.
-3d is a subscriber line that accommodates packet switching equipment 1a or 1d.

Here, each packet switch 1a to 1d independently assigns "0" and "1" to the trunk lines 2a to 2e and subscriber lines 4a to 4d accommodated therein.
,... route numbers are assigned.

Further, 5a is a packet sent from the terminal device 3a to 3d, and 5b is a packet sent from the terminal device 3d to 3a. FIG. 5 shows the format of the packets 5a and 5b.

In the figure, 10 is a flag (F) indicating the start and end of a packet, and 11 is its link address (A).
), 12 is a control field command (C) for link control, and 13 is a frame check sequence (FCS) for error checking.

Reference numeral 14 indicates data to be transmitted, and reference numeral 15 indicates route information in which the route numbers at each packet switch 1a to 1d to which the packets 5a and 5b are relayed are arranged in the order of the packet switches 1a to 1d to which the packets 5a and 5b are relayed. This is the sent header. In FIG. 4, this data 14 and transmission header 1
5 are shown as packets 5a and 5b.

Reference numerals 6a to 6d are detour tables provided in each of the packet switches 1a to 1d. These detour tables 6a to 6d are provided for each packet switch 1.
The route number assigned to each trunk line 2a to 2e in a to 1d is the current route number, and each of the trunk lines 2a to 2 to which the route number is assigned is set to the current route number.
Each route number on a detour route to be detoured when a failure occurs in e is associated as a detour route number.

FIG. 5 shows this detour table 6a provided in the packet switch 1a. FIG. 5 shows an example where the route number "3" of the trunk line 2b is used as the current route number, and in the column of the detour route number, the relay line 2
Each route number of two detour routes when a failure occurs in e is written.

That is, on the one hand, the route number of the trunk line 2a in the packet switch 1a of the detour route from the trunk line 2a to the packet switch 1b to the relay control relay line 2c is shown.
2" and the route number "1" of the trunk line 2c in the packet switch 1b are written, and the relay in the packet switch 1a of the detour route of the trunk line 2b → packet switch 1c → trunk line 2d is written in the other side. The route number "4" of the line 2b and the route number "1" of the trunk line 2d in the packet switch 1c are written.

The following operation will be explained. Terminal device 3a
When a call is set up between terminal devices 3a and 3d, during normal operation, a predetermined route number "3,0" or "2" is set in the transmission header 15 between both terminal devices 3a and 3d as in the conventional case , 1'' are sent and received.

If a failure occurs in the trunk line 2e, the packet switch 1a detects the failure and refers to the detour table 6a based on the route number "3" of the trunk line 2b. Then, one of the two detour route numbers associated with the current route number "3" is selected to determine the detour route, taking into consideration priorities, traffic, and the like.

[0013] If the detour route number "2,1" is selected, then when the packet switch 1a receives a packet whose first route number in the route information in the transmission header 15 is "3", it will change the route number to “2” extracted from “3”
, 1", and then perform its routing.

[0014] Therefore, the packet 5a from the terminal device 3a
is sent to the trunk line 2a according to the route number "2" at its tip. At this time, as in the conventional case, the route number "2" used for the routing in the route information is removed, and the route number in the transmission header 15 becomes "1,0" as shown in FIG.

The packet switch 1b transmits the packet 5a based on the leading route number "1" in the transmission header 15.
The packet 5a from which the route number "1" has been removed is sent to the packet switch 1d. Therefore, the packet 5a having the same route information as before the detour arrives at the packet switch 1d.

The packet switch 1d performs routing according to the route information of the received packet 5a, and sends the packet 5a to the terminal device 3d. This packet 5a
Accordingly, data from the terminal device 3a is transmitted to the terminal device 3d without being interrupted due to a failure of the relay line 2b.

Similarly, when the packet switching device 1d detects a failure in the trunk line 2e, it refers to the detour table 6d based on the route number "2" of the trunk line 2b and selects a detour route number "1," for example. 0” detour route is selected. After that, when this packet switch 1d receives a packet whose initial route number is "2", it changes the route number from "2" to "1,0", performs routing, and routes the packet 5b from the terminal device 3d. Relay line 2
Send to c.

[0018] Routing is then performed in the packet switches 1b and 1a using the corresponding route number, and the terminal device 3d is
data is transmitted to the terminal device 3a by a packet 5b.

[0019]

[Problems to be Solved by the Invention] Since the routing system in the conventional data switching network is configured as described above, each packet switch 1a to 1d as a data switch
The number of detour tables 6a to 6d provided in the internal memory increases as the network grows, and one of the available routes must be selected for relay route selection, making it difficult to process each packet data. However, there were problems such as the time it took to determine the relay route.

[0020] This invention was made to solve the above-mentioned problems, and it provides a routing method in a data exchange network in which traffic is considered in terms of the number of calls and routes can be selected in a very simple manner. The purpose is to obtain a method.

[0021]

[Means for Solving the Problems] The routing method in the data exchange network according to the present invention is such that a relay route call counter is provided in the data exchange equipment to store the number of calls used for each relay route. etc., the average number of relay route calls is calculated by dividing the total number of calls at that point by the number of normal relay routes. In addition to distributing calls according to the number of relay route calls, when a failed relay line becomes available due to failure recovery, etc., the average number of relay route calls including the relay route that has become available is calculated, Among the calls using the existing relay route, calls exceeding the average number of calls on the relay route are switched to the available relay route.

[0022]

[Operation] The routing method in the data exchange network according to the present invention is such that a relay route call counter stores the number of calls being used for each relay route, and the number of calls being used for each relay route is stored in a relay route call counter, so that the number of calls used for each relay route is stored, and the number of calls used for each relay route is stored, and the number of calls used for each relay route is stored in a relay route call counter. By calculating the average number of relay route calls at that time, or when the service becomes available due to failure recovery, etc., and distributing calls evenly to all available relay routes based on that, traffic can be reduced in terms of the number of calls. To realize a routing method in a data exchange network that can take consideration into determining a detour route and shorten processing time for route selection.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1a to 1d are packet switches serving as data exchanges, 2a to 2f are relay lines, and 3a to 3d are
4 is a terminal device, and 4a to 4d are subscriber lines, which are the same or equivalent parts to those of the conventional system denoted by the same reference numerals in FIG. 4, and therefore detailed explanation will be omitted.

Reference numerals 7a to 7d designate relay route call counters that are placed in each of the calling stations accommodated in the packet exchanges 1a to 1d, and store the number of calls being used for each relay route. For example, FIG. 2 shows the configuration of the relay route call counter 7a located in the originating station of the packet switch 1a. That is, this relay route call counter 7a has an element 71 that stores the number of calls on the relay route (2) by the relay line 2a→2c,
an element 72 that stores the number of calls for relay route ■ from 2f to 2d;
Element 73 that stores the number of calls on relay route ■ by relay line 2e
, an element 74 that stores the number of calls made via the trunk line 2b→2d.

Next, the operation will be explained.

[0026] Now, when trying to set up a plurality of calls between the terminal devices 3a and 3d, in normal conditions, for example, by referring to a detour table using a relay path fixed method that takes priority and traffic into consideration, Said relay route ■→■→■→■→■
→ Calls are placed cyclically on average to each relay route as follows. Note that each of the elements 71 to 74 of the route call counter that stores calls for each relay route increases the counter by 1 when one call is set up, and decreases the counter by 1 when the call is disconnected.

Now, as shown in FIG. 3(a), when two calls are connected to each relay route ■ to ■, if a failure occurs in the relay line 2c, first the relay route The contents of the element 71 of the call counter 7a, which has information on the number of calls on the relay path (2) including this relay line 2c, are cleared to zero.

[0028] Here, if the relay line 2e is congested, the total number of calls connected to the normal relay route excluding the congested relay route (■) is 6, and the number of calls that cannot be used due to the occurrence of a failure is 6. Since there are now two normal relay routes, the average number of relay route calls is calculated to be three. Therefore, the relay route ■,
Assign one to each normal relay route in (2). Note that since relay route (3) is congested, calls are not distributed to the relay route.

[0029] Therefore, the relay route to which calls are distributed one by one is
The values of the respective elements 72 and 74 of the relay route call counter 7a associated with , and ■ are 3, respectively. The situation is shown in FIG. 3(b).

On the other hand, as shown in FIG. 3(c), for example, calls 3, 1, and 3 are placed on the relay routes ■ to ■, and the corresponding elements 71 to 74 of the relay route call counter 7a are respectively filled. The number of calls 3, 1, 3 is memorized, and when relay route ■ is congested, the number of calls on the normal route is divided so that the number of calls on the normal route, including the relay route that has become available, is equalized. Among them, calls whose number exceeds the average number of relay route calls are distributed equally.

That is, the number of normal relay routes becomes three due to the failure recovery of the relay line 2c, and the total number of calls excluding the calls placed on the congested relay route is six. Therefore, the average number of relay route calls is 2, and the calls are distributed so that two calls are assigned to each of the normal relay routes (2), (2), and (3).

[0032] In this way, the relay route ■, which was already normal,
The number of calls placed on each of the relay routes in ■ is 3, so the number of calls in excess of the equal relay route number of 2 is distributed one by one to the relay route in the available relay route ■.
Assume that the number of calls allocated to the relay route that has become available is two. The situation is shown in FIG. 3(d).

[0033]Thus, it is possible to easily and immediately switch relay routes without discarding calls.

[0034]

As described above, according to the present invention, a relay route call counter that stores the number of calls being used for each relay route is provided, and when a failure occurs and when a failure is recovered, each Since the system is configured to distribute calls evenly to normal relay routes, it is possible to always take traffic into consideration regarding the number of calls on each relay route when placing calls, and to make detours without taking almost any processing time for route selection. This has the effect of providing a routing method in a data exchange network that can be used.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a routing method in a data exchange network according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the configuration of the relay route call counter.

FIG. 3 is an explanatory diagram showing the operation of the relay route call counter when a relay line failure occurs and when the failure is recovered.

FIG. 4 is a block diagram showing a routing method in a conventional packet switching network.

FIG. 5 is an explanatory diagram showing the format of packets transmitted in a conventional packet switching network.

FIG. 6 is an explanatory diagram showing the configuration of a detour table used therein.

[Explanation of symbols]

1a~1d Data switch (packet switch) 2a~
2f Trunk line 3a to 3d Terminal device 4a to 4d Subscriber line

Claims (1)

[Claims] 1. A data exchange network is constituted by a plurality of data exchanges, and a plurality of relay routes are provided between the data exchanger accommodating a terminal device on the originating side and the data exchanger accommodating the terminal device on the terminating side. When setting up a call, one of the relay routes selected in consideration of a predetermined priority or traffic volume is assigned as the route to be used for relaying the call, and subsequent data is In a routing method in a data exchange network in which transfer is performed using the assigned relay route,
A relay route call counter is provided in the data exchanger to store the number of calls being used for each relay route, and one or more of the relay routes may be used due to a failure of a relay line forming the relay route, etc. When it becomes impossible,
When switching a call that was using the faulty relay route to a normal relay route, the total number of calls set between the faulty relay route and the partner station of the normal relay route is
The average number of relay route calls is calculated by dividing by the number of normal relay routes at that time, and the calls that were using the failed relay route are transferred to each of the normal relay routes, resulting in the average number of relay route calls. Furthermore, when one or more of the failed relay routes becomes available due to failure recovery of the relay line, etc., the average number of calls on the relay route including the relay route that became available is calculated. Calculated in the same way, calls that exceed the average number of relay route calls among calls using the previously normal relay route are switched so that they are evenly distributed to the relay route that has become available. A routing method in a data exchange network characterized by the following: