JPH08191328A - Automatic route selection device - Google Patents

Abstract

PURPOSE: To prevent a communication from being delayed in a time zone wherein the frequency of communication is high by selecting a route according to the communication time zone and the priority of the communication. CONSTITUTION: Priority is set for a packet communication terminal. In the busy time zone wherein a communication is made frequently, the shortest route or a by-pass route is selected by a route selection part 4 according to the priority. Namely, the shortest route which is registered in a shortest-route selection table 1 is selected preferentially for a packet of high priority, but the by-pass route which is registered in a by-pass route selection table 2 is selected for a packet of low priority. Consequently, the packet of low priority is automatically made to take the by-pass route and the packet of high priority can preferentially takes the shortest route without being disturbed by the packet of low priority. In a time zone wherein the communication is not so frequent, either of the packets take the shortest route. Consequently, the by-pass route is not taken unnecessarily except in the frequent communication time zone and the communication capability of the communication network is effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic route selecting device for selecting an appropriate route according to the priority of communication according to a communication time zone in communication of a packet switching station.

[0002]

2. Description of the Related Art In packet communication, a packet is transmitted from a transmitting station to a receiving station via a plurality of exchanges. In this case, a communication network is composed of communication lines connected between the respective exchanges, and there are a plurality of communication paths from the transmitting station to the receiving station. Each such communication path is called a route. That is, the route is a communication path from the transmitting station to the receiving station via the communication line and the switching center, and the distance thereof is from the shortest to the longest. Therefore, on the transmitting station side, a plurality of routes for each receiving station are respectively registered and managed by the distance. That is, in the conventional route selection device, the first route, the second route, etc. are set in order from the route with the shortest distance, and the first route is first selected in the packet communication.
When the first route is abnormal such as congestion or failure, the second route and the subsequent routes are sequentially selected.

[0003]

However, the above-mentioned conventional techniques have the following problems. That is, when packet communication is frequently performed, congestion occurs due to the concentration of communication to the same route, which results in a large number of retransmissions, and as a result, communication delay often occurs. In this case, when the communication with the low priority is started first, the communication with the high priority is delayed. On the other hand, if the communication network is configured so as to be able to handle the case where the packet communication is most frequently performed, the cost is increased and the communication capacity is wasted when the communication is infrequent in many time zones.

[0004]

In order to solve the above-mentioned problems, the automatic route selection device of the present invention is characterized by the following points. (1) Register the routes with the shortest distance from the transmitting station to the receiving station in order,
A shortest route selection table is provided for sequentially preferentially selecting the shortest route for a packet having a high communication priority. A detour route selection table is provided for avoiding a route having a short distance from the transmitting station to the receiving station and forcibly selecting a route bypassing the route when transmitting a packet having a low communication priority. A busy time period registration unit for registering a predetermined time period in which communication is frequently performed is provided. Only in a predetermined time zone registered in the busy time zone registration section, a detour route for transmitting a packet having a low communication priority is selected by the detour route selection table,
The shortest route selection table is used to sequentially select the shortest routes for transmitting packets with high communication priority, and the packets with high communication priority are transmitted using the shortest route selection table except during a predetermined time period. And a route selection unit that sequentially selects the shortest route of

(2) In (1), the predetermined time zone registered in the busy time zone registration section is characterized by being the busiest time zone in which communication is most frequently performed.

[0006]

[Action]

(1) Priorities are set for packet communication terminals. In a busy time period when communication is frequently performed, the shortest route or the detour route is selected by the route selection unit according to the priority. That is, the shortest route registered in the shortest route selection table is preferentially selected for a packet with high priority, but the detour registered in the detour route selection table is selected for a packet with low priority. A route is selected. As a result, low priority packets are automatically detoured, and high priority packets can be preferentially acquired for the shortest route without being blocked by low priority packets. In addition, in a time period in which communication is not so frequently performed, the shortest route is selected regardless of the priority of the packet. As a result, during a busy communication period, unnecessary detours are not made and the communication capacity of the communication network is effectively utilized.

(2) In (1), as a result of selecting a detour route for a packet having a low priority only in the busiest time zone where communication is most frequent, a packet having a high priority is efficiently made only in the busiest time zone. , And the communication capacity of the communication network can be effectively utilized in all other time zones.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of the automatic route selection device of the present invention. The illustrated apparatus includes a shortest route selection table 1, a detour route selection table 2, a busy time zone registration unit 3, and a route selection unit 4. The shortest route selection table 1 is composed of a part of the storage device of the exchange and registers the route R1 having the shortest distance as the first route. Here, the route is a communication path from the transmitting station to the receiving station via the communication line and the switching center, and as shown in FIG. 2, R1, R2,
There are multiple Rn and the like. In addition, in the shortest route selection table 1, the route R2 in which the distance from the transmitting station to the receiving station is the next shortest is registered as the second route, and the routes up to the n-th route are sequentially registered.
Then, with such a shortest route selection table 1, the route selecting unit 4 sequentially selects the shortest route preferentially for packets having high communication priority.

The detour route selection table 2 is made up of a part of the storage device of the exchange, and the route having the longest distance is the first route, which is opposite to the shortest route selection table 1, and the second route in the following order. The routes are registered in the order of increasing distance from the route to the n-th route. The registration of the route in the detour route selection table 2 is not limited to such an example, and any other registration may be performed if the route other than the shortest route R1 is not set as the first route. It may be a method.
As a result, when transmitting a packet having a low communication priority, the route R1 having the shortest distance from the transmitting station to the receiving station is avoided, and a route bypassing the route R1 is forcibly selected.

The busy time zone registration unit 3 is composed of a part of the storage device of the exchange and registers a predetermined time zone in which communication is frequently performed. For example, “17:30 to 18:00” or the like is registered as the busiest time zone during the day. Such time zones may be registered together with other time zones other than the busiest time zone when communication is busy. That is, a plurality of time zones may be registered. Also, what day of the week is 1
Any other time zone such as days of the month, months of the year or days of the month may be set.

The route selection unit 4 selects the detour route selection table 2 only during a predetermined time period registered in the busy time period registration unit 3.
Selects a detour route for transmitting a packet having a low communication priority. Along with this selection, the shortest route selection table 1 sequentially selects the shortest route for transmitting a packet having a high communication priority. On the other hand, except in a predetermined time zone, the shortest route for transmitting a packet having a high communication priority is sequentially selected only by the shortest route selection table 1 as in the conventional case.

Next, the operation of the above-mentioned device will be described. As an example, in FIG. 2, a route registration procedure for a receiving station and a route selection method when performing packet communication from PS-A to PS-E will be described. FIG. 2 shows a route registration procedure for receiving stations for each packet communication terminal. In PS-A, the route is registered by the procedure of and in the figure. R1 to Rn are registered in the shortest route selection table 1 for PS-E and the detour route selection table 2 for PS-E as routes for PS-E. Here, the detour route selection table 2 indicates the routes that can be used from the routes registered for the receiving station when performing packet communication from a packet communication terminal having a low priority during the busy hour. It is a table used when selecting. The procedure of route registration is the same as that of the shortest route selection table 1 for PS-E.

The busiest time zone is registered. That is, the time zone such as “17:30 to 18:00” is registered in the busy time zone registration unit 3. The priority is registered in the packet communication terminal. That is, for example, “priority” is set for a priority terminal, and “non-priority” is set for a non-priority terminal. Information necessary for route selection for PS-E is registered using the above procedure.

FIG. 3 shows a route selection procedure for the receiving station for each packet communication terminal. When performing packet communication, first, a transmission request is accepted in step S1, and then step S2
In step S3, the clock information is read, and it is determined in step S3 whether the current time is in the busiest time zone. If the current time is not in the busiest time zone, skip step S4 and go to step S4.
In step 5, a usable route is selected from the shortest route selection table 1 for PS-E.

On the other hand, when the current time is in the busiest time zone, the priority of the packet communication terminal is determined in step S4. When communicating from a packet communication terminal with a high priority, a route is always selected from the shortest route selection table 1 for PS-E in step S5. When the current time is the busiest time zone in step S3 and the communication is from the packet communication terminal with low priority in step S4, a route that can be used from the detour route selection table 2 for PS-E is used. Select. Then, in step S7, the states of the routes are sequentially determined from the first route of the selected shortest route selection table 1 or the detour route selection table 2. When the state of the route is other than normal (fault, congestion, etc.), the same determination is made in order of the second route and the third route in steps S8 and S7, and the normal route is selected. . After that, the packet is transmitted through the route.

In this way, a detour route is assigned to a packet transmitted from a packet communication terminal having a low priority so that transmission of a packet transmitted from a packet terminal having a high priority is not hindered. As a result, communication delay can be prevented and smooth communication can be performed. In the above-described embodiment, the route selection method when only one detour route selection table 2 for PS-E is registered for PS-A has been described. It is possible to register a plurality of detour route selection tables 2 in the same station, and it is possible to determine a route for the receiving station by selecting one of the tables for each busy hour.

[0017]

As described above, according to the automatic route selection device of the present invention, the packet having the low priority is forcibly bypassed only in the predetermined time zone, and therefore the following effects are obtained. There is. That is, it is possible to avoid that communication having a low priority is distributed to the detour route and the communication to the same route is concentrated in a predetermined time period in which packet communication is frequently performed. Therefore, it is possible to prevent the occurrence of congestion, and it is possible to prevent the communication of packets having a high priority from being delayed by the retransmission. On the other hand, the configuration of the communication network only needs to support the case where only high-priority packet communication is carried out most frequently, so there is no need to support the maximum communication volume including low-priority packet communication. Therefore, the cost can be reduced. In addition, during times when communication is infrequent, packet communication with a low priority can be performed, and communication capacity can always be effectively utilized.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of an automatic route selection device of the present invention.

FIG. 2 is an explanatory diagram of a route registration procedure for a receiving station for each packet communication terminal.

FIG. 3 is a flowchart illustrating a route selection procedure according to the present invention.

[Explanation of symbols]

 1 Shortest route selection table 2 Detour route selection table 3 Busy time zone registration unit 4 Route selection unit

Claims (2)

[Claims] 1. A shortest route selection table for sequentially registering routes having a short distance from a transmitting station to a receiving station and sequentially preferentially selecting a shortest route for a packet having a high communication priority. And a detour route selection table for avoiding a route with a short distance from the transmitting station to the receiving station and forcibly selecting a route that bypasses this when transmitting a packet with a low communication priority. The busy time slot registration unit that registers a predetermined time slot that is frequently used, and the packet with low communication priority by the bypass route selection table only in the predetermined time slot registered in the busy time slot registration unit. While selecting a detour route for transmitting a packet, and sequentially selecting a shortest route for transmitting a packet having a high communication priority by the shortest route selection table, and selecting the shortest route other than the predetermined time zone. Route selection table An automatic route selection device comprising: a route selection unit that sequentially selects a shortest route for transmitting a packet having a high communication priority. 2. The automatic route selection device according to claim 1, wherein the predetermined time period registered in the busy time period registration unit is a busiest time period in which communication is most frequently performed.