JPH07115434A - Routing device - Google Patents

Abstract

PURPOSE:To freely operate the load distribution of traffic by providing a route register means where plural routes are registered in a preliminarily determined ratio, a means which successively reads out routes from the register means, and a route selecting means. CONSTITUTION:A packet analysis part 11 translates the destination of the packet sent from a terminal 30, and a routing control part 12 selects a transmission route of the packet translated by the analysis part 11. A memory 13 has a successive route selection table T1 and an arbitrary route selection table T2, and they are used for transmission route selection by the control part 12. A packet transmission control part 14 sends the packet, to the route selected by the control part 12. When a call occurs, a route R1 is read out from the first address of the table T1, and it is discriminated, whether the packet can be transmitted through the route R1 or not. When it can be transmitted, the route R1 is determined as the transmission route. If it cannot be transmitted, a route 93 is read out from an address of the table T2, and the route R3 is determined when the packet can be transmitted through the route R3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a routing device for selecting a route capable of transmitting a packet from a plurality of routes in a packet communication network having a plurality of routes.

[0002]

2. Description of the Related Art Generally, in a packet communication network having a plurality of routes, each packet switching station is provided with a routing device for selecting a route capable of transmitting a packet from the plurality of routes.

A conventional routing device selects a route capable of transmitting a packet by prioritizing each route in advance and determining whether or not a packet can be transmitted for each route according to this priority. It is like this.

This will be described using the packet communication network shown in FIG. FIG. 2 shows four packet switching stations PS1 and PS.
2 shows a packet communication network composed of 2, PS3 and PS4.

In FIG. 2, it is now assumed that a packet is transmitted from the exchange PS1 to the exchange PS2. In this case, the packet transmission route includes a route R1 directly transmitted to the exchange PS2, a route R2 transmitted via the exchange PS3, and a route R3 transmitted via the exchange PS4.

Priorities are assigned to the routes R1, R2 and R3 in advance based on, for example, the number of relay stations, the line speed, the number of lines, and the like. The three routes R1, R2, R3 are registered in the route selection table in order of priority.

FIG. 3 shows a route selection table for the exchange PS2. The figure shows a case where the route R1 has the highest priority, the route R2 has the second highest priority, and the route R3 has the lowest priority.

In such a configuration, the exchange PS1
At this point, when a call destined for the exchange PS2 occurs,
First, the route R1 having the highest priority is read from the route selection table for the exchange PS2.

Next, it is judged whether or not the route R1 can transmit a packet. If the packet can be transmitted, this route R1 is selected as the packet transmission route. On the other hand, if the transmission is impossible, the next route R2 is read and determination processing is performed.

Thereafter, similarly, the reading and determination processing is performed for each route until a route capable of transmitting the packet is found.

Assuming that the route R3 is selected by this processing, the packet is transmitted from the exchange PS1 to the route R3.
3 to the exchange PS4. As a result, the above-mentioned processing is also performed in this exchange PS4.

In this case, there are two routes, RA and RB. Now, assuming that the route RA has a higher priority, the route selection table for the exchange PS2 provided in the exchange PS4 has RA, R as shown in FIG.
The routes are registered in the order of B.

As a result, in the exchange PS4, the route is read out and the determination process is performed in order from the route RA. By this processing, for example, when the route RA is selected as the packet transmission route, the packet is transmitted from the exchange PS4 to the exchange PS2 via the route RA.

If a route capable of transmitting a packet is not found by the route selection process described above,
The packet cannot be transmitted.

[0015]

As described above, the conventional routing device determines the priority order for each route in advance and determines whether or not the packet can be transmitted according to this priority order. ing.

However, in such a configuration, even when there are a plurality of routes having substantially the same priority,
Among them, the route with the higher priority is preferentially selected, so that the traffic is biased and the throughput in the network is reduced.

In other words, the conventional routing device has a problem in that even if there are a plurality of routes for which the load of the traffic can be evenly distributed, this cannot be done.

Therefore, an object of the present invention is to provide a routing device capable of freely controlling the load distribution ratio of traffic.

[0019]

In order to achieve the above object, the invention according to claim 1 registers a plurality of routes at a predetermined ratio, and the read start position of the registered route is a route selection request. In this case, the data is updated one by one due to the occurrence of.

Further, in the invention according to claim 2, in a routing device for selecting a route according to a predetermined priority, a route having a high priority is subjected to route selection processing according to the priority, and a route having a low priority is executed. With regard to (1), route selection processing is executed according to the invention of claim 1.

[0021]

In the invention according to claim 1, when a route selection request is generated (for example, a call is generated), the route selection process is started from a certain route registration position. After this, when the next route selection request is generated, this time, when the previous route selection request is generated, the route selection processing is started from the position next to the position where the route reading is started. As a result, the traffic is load-balanced according to the registration ratio of each route. Therefore, by appropriately setting this registration ratio, the traffic load distribution ratio can be freely manipulated.

According to the second aspect of the present invention, when a call occurs, first, the route selection process according to the priority order is executed for the route with the higher priority order. If a route is found in this route selection process, the process ends at that point.

On the other hand, when the route is not found, the same route selection process as that of the invention according to claim 1 is executed for the route having the lower priority. This allows
In the low priority portion, the traffic is load-balanced according to the registration ratio of each route. Therefore, if the registration ratios are made uniform, it is possible to eliminate the deviation of traffic between routes having almost the same priority.

[0024]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. However, FIG. 1 shows the overall configuration of a packet switch equipped with the routing device of the present invention.

In the figure, reference numeral 10 is a packet switch provided in the switching center PS. This packet switch 10
It has a packet analysis unit 11, a routing control unit 12, a memory 13, and a packet transmission control unit 14. here,
The routing device to which the present invention is focused comprises a routing control unit 12 and a memory 13.

The packet analysis unit 11 is connected to the terminal 30 via the terminal line 20, for example, and translates the destination of the packet sent from the terminal 30. The routing control unit 12 selects the transmission route of the packet whose destination is translated by the packet analysis unit 11.

The memory 13 holds a route selection table used when the routing controller 12 selects a packet transmission route. The packet transmission control unit 14 sends the packet to the route selected by the routing control unit 12. The routing control unit 14 determines the number N of routes.
Only provided.

The above is the overall configuration of one embodiment. Next, registration of a route in the route selection table will be described.

This route selection table includes a sequential route selection table T1 and an arbitrary route selection table T2. In the sequential route selection table T1, routes with higher priorities are registered. On the other hand, in the arbitrary route selection table T2, routes other than the routes sequentially registered in the route selection table T1, specifically, routes with low priority and almost the same priority are registered.

In this case, the registration of the routes in the sequential route selection table T1 is performed in the order of priority as in the conventional route registration in the route selection table. On the other hand, routes are registered in the arbitrary route selection table T2 according to a predetermined ratio regardless of the priority order. This ratio matches the traffic load distribution ratio for each route. This load distribution ratio is set by the designer of the network.

The tables T1 and T2 are provided for each destination.

Here, using the packet communication network of FIG.
An example of registration of a route with respect to the tables T1 and T2 will be described.

Now, assume that a packet is transmitted from the exchange PS1 to the exchange PS2 in the packet communication network of FIG. The routes in this case include a route R1 directly transmitted to the exchange PS2, a route R2 transmitted via the exchange PS3, and a route R3 transmitted via the exchanges PS4 and PS5.

Priorities are given to the routes R1, R2 and R3 in advance. Now, it is assumed that the priority order is higher in the order of R1, R2 and R3. It is also assumed that the routes R2 and R3 have substantially the same priority.

In such a case, only the route R1 is registered in the sequential route selection table T1 as shown in FIG. 6, for example. On the other hand, as shown in FIG. 7, routes R2 and R3 are registered in the arbitrary route selection table T2.

As described above, the routes R2 and R3 are registered based on the load distribution ratio of the traffic required for the routes R2 and R3. In the figure, this ratio is R2:
The case where R3 = 2: 1 is shown.

When the routes R2 and R3 are registered, the number of registrations and the order of registration are not limited as long as the ratios comply with a predetermined ratio. In the figure, as an example, after registering two routes R2, one route R1 is registered.
The case where two registrations are repeated twice is shown.

The above is the method of registering a route in the route selection table. Next, the processing of the routing control unit 12 will be described with reference to FIG.

The processing shown is executed each time a call occurs. Further, this process is performed by sequentially selecting the route selection table T1.
Route selection process and optional route selection table T2
It can be divided into route selection processing using. Hereinafter, the former route selection process is called sequential route selection process, and the latter route selection process is called arbitrary route selection process.

When a call occurs, first, route selection processing is sequentially performed. In this sequential route selection process, if the packet transmission route cannot be found, the arbitrary route selection process is performed for the first time.

The sequential route selection table T1 is accessed in the order of priority as in the conventional case. Therefore, when routes with higher priority are registered in order from the head address A, the table T1 is accessed in order from the head address.

On the other hand, the arbitrary route selection table T2
The access is performed by sequentially updating the read start address (read start position) each time a route selection request is generated. In the case of this embodiment, the time when the route selection request is generated is not the time when the call is generated,
This corresponds to the case where a route cannot be found by the sequential route selection processing.

The processing of FIG. 8 will be described in detail. In the sequential route selection process, first, the route having the highest priority is read from the head address of the table T1 (step S1). Next, it is determined whether or not this route can transmit a packet (step S2).

When the determination result that the packet can be transmitted is obtained by this determination processing, this route is determined as the packet transmission route (step S3). On the other hand, when the determination result that the packet cannot be transmitted is obtained, it is determined whether or not the processing for all the routes is completed (step S4).

If it is determined by this determination processing that the processing has not ended, one read address is updated (step S5). Then, the process returns to step S1. This allows
This time, the above-described processing is performed on the route having the second highest priority.

Similarly, the above-mentioned processing is executed until a route capable of transmitting a packet is found. If the route to which the packet can be transmitted is not found even after reaching the last route, the arbitrary route selection process is started.

In this process, first, the read start address is obtained (step S6). The read start address is designated by, for example, a counter provided inside the routing controller 12. Therefore, in this case, the read start address is obtained by reading the value of this counter.

Thereafter, similar to the sequential route selection process, the process of selecting the route capable of transmitting the packet while sequentially updating the read address is performed (steps S7 to S).
10).

However, in this arbitrary route selection processing, if no route capable of transmitting the packet is found, it is determined that the packet cannot be transmitted (step S12).

Whether the route capable of transmitting the packet is found or not found, the value of the read start address designation counter is updated by 1 (step S13). This allows
When the next route selection request is generated, the arbitrary route selection process is started from the address next to the previous read start address.

The above is the route selection processing by the routing control unit 12. Here, the route selection process described above will be further described using the examples of FIGS.

In the case of this example, when a call destined for the exchange PS2 occurs, first, the route R1 is sequentially read from the head address A1 of the route selection table T1 (step S1). Next, it is determined whether or not this route R1 can transmit a packet (step S2).

If transmission is possible, this route R1 is determined as the packet transmission route (step S3). On the other hand, if transmission is impossible, an arbitrary route selection process is performed. This is because, in this example, only one route is registered in the sequential route selection table T1.

In the arbitrary route selection process, first, the read start address is obtained (step S6). If this read start address is, for example, A3, then the route R3 is read from this address A3 (step S7).

Thereafter, it is judged whether or not the route R3 can transmit the packet (step S8). If the packet can be transmitted, this route R3 is determined as the packet transmission route (step S9).

Thereafter, the value of the read start address designation counter is updated by 1 (step S13). This allows
When the next route selection request is generated, the route selection process is started from the address A4 this time.

On the other hand, if the packet cannot be transmitted, the read address is updated by 1 (step S).
11). As a result, this time, the above-described processing is performed on the route R2 registered in the address A4.

Similarly, the above-described processing is performed until a route capable of transmitting a packet is found. Even if the route to the final address A6 is reached, if no route capable of transmitting the packet is found, the process returns to the start address A1 and
The process is executed until the address A2 immediately before the read start address A3 is reached.

If the route cannot be found even though the address A2 is reached, it is determined that the packet cannot be transmitted (step S12). After that, the value of the read start address designation counter is updated by 1, and the process ends.

According to this embodiment described in detail above, the following effects can be obtained.

(1) First, a plurality of routes having a low priority and almost the same priority are registered in accordance with a predetermined ratio, and their read start addresses are sequentially updated. The load distribution ratio of traffic on various routes can be freely manipulated. As a result, it is possible to prevent the traffic from being biased to a route having a higher priority among these routes.

(2) Further, a plurality of routes are divided into two groups, and a route having a high priority is subjected to the route selection process according to the priority as in the conventional case. While making the most of
The conventional problem can be solved.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to such an embodiment.

(1) For example, in the above embodiment, the case where the arbitrary route selection process is performed on a plurality of routes having a low priority and the same priority is described. However, in the invention according to claim 2, the route that satisfies only the condition that the priority is low may be subjected to the arbitrary route selection processing.

(2) Further, in the above embodiment, the case where the arbitrary route selection process is applied to a plurality of routes having a low priority has been described. However, in the invention according to claim 1, the arbitrary route selection process may be performed on a route having a high priority, or the arbitrary route selection process may be performed on all routes.

(3) Further, in the above embodiment, the case where the arbitrary route selection process is sequentially combined with the route selection process has been described. However, in the invention according to claim 1, the arbitrary route selection process may be combined with the route selection process other than the sequential route selection process.

(4) In addition to the above, the present invention can be variously modified without departing from the scope of the invention.

[0069]

As described in detail above, according to the present invention, it is possible to provide a routing device capable of freely controlling the load distribution ratio of traffic.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a packet communication network for explaining a conventional route selection process.

FIG. 3 is a diagram showing a conventional route selection table for PS1 → PS2.

FIG. 4 is a diagram showing a conventional PS4 → PS2 route selection table.

FIG. 5 is a diagram showing a packet communication network for explaining route selection processing according to an embodiment.

FIG. 6 is a diagram showing a sequential route selection table T1 for PS1 → PS2 according to an embodiment.

FIG. 7 is a diagram showing an arbitrary route selection table T2 for PS1 → PS2 according to an embodiment.

FIG. 8 is a flowchart showing an operation of a routing control unit of one embodiment.

[Explanation of symbols]

10 ... Packet switch, 11 ... Packet analysis unit, 12 ...
Routing control unit, 13 ... Memory, 14 ... Packet transmission control unit, T1 ... Sequential route selection table, T2 ... Arbitrary route selection table.

Claims (2)

[Claims] 1. In a routing device in a packet communication network, a route registration means in which a plurality of routes are registered at a predetermined ratio, and a read start position is sequentially updated each time a route selection request is issued, Route reading means for sequentially reading the routes from the route registration means, and route selection for selecting a route capable of transmitting packets by determining whether the route read by the route reading means is capable of transmitting packets And a routing device. 2. A routing device in a packet communication network for selecting a packet transmission route from a plurality of routes in accordance with a predetermined priority order, wherein a route having a higher priority order among the plurality of routes is registered in the order of the priority order. A first route registration means, and a second route registration means in which routes other than the routes registered in the first route registration means are registered at a predetermined ratio among the plurality of routes; First route reading means for sequentially reading the routes from the first route registration means in the order of priority, and whether the route read by the first route reading means is capable of transmitting packets. First route selection means for selecting a route capable of transmitting a packet by determining whether or not the first route selection means Second route reading means for sequentially reading the routes from the second route registration means so that the reading start position is updated each time a route is not selected by the means, and the second route. A routing device comprising: second route selecting means for selecting a route capable of transmitting a packet by determining whether or not the route read by the reading means is capable of transmitting a packet.