JP2003218917A - System and method for distributing traffic using ospf cost - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a system and method for distributing traffic using the OSPF (open shortest path first) cost which enable distribution of traffic by temporarily and automatically increasing the cost of a link at a particular position when the traffic is concentrated on the particular position in a network employing the OSPF for the routing protocol. <P>SOLUTION: Each router being a component of the network monitors the amount of transmission data sent from a link interconnecting the routers, automatically revises the link cost preset to the link when the amount of transmission of a link exceeds a preset threshold for the amount of the transmission data to update the optimum routing in the network by the OSPF and transmit succeeding transmission data to the updated optimum routing thereby revising the amount of transmission data from the link and distributing the traffic. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an OSPF (Open).
Shortest Path First) The present invention relates to a traffic distribution method and a traffic distribution method using cost, and in particular, OSPF as a routing protocol.
In a network using the OS, when traffic is concentrated at a specific place in the network, it is possible to distribute traffic by automatically and temporarily increasing the cost of the link at the specific place.
The present invention relates to a traffic distribution method and a traffic distribution method using a PF cost.

[0002]

2. Description of the Related Art OSPF is a routing protocol widely used on the Internet. Based on the topology information of the target network, OSPF is based on the cost attached to each link and SPF (Shortest Pas).
A method of performing routing (route selection) by the th First algorithm is adopted.

In OSPF, when there are a plurality of routes for transmitting data to a certain destination, in calculating an optimum route to the destination, it is set to each link connecting each router constituting the network. The cost is used to determine the route that minimizes the total cost of multiple links to the destination as the optimal route. The cost of each link is set by a command by a network maintainer in consideration of the capacity of each link.

[0004]

Since the optimum route in the above-mentioned OSPF is determined only by the cost of the link, a plurality of optimum routes for a plurality of destinations are determined so as to pass through a specific link having a low cost. There is a great possibility that When a large amount of traffic is generated for multiple destinations in a network where the optimal route is determined in this way, it is determined as the optimal route even if other links are free. There is a problem that the traffic is concentrated on the specified specific link and the specific link becomes in a congestion state.

A specific example will be described with reference to FIG.

In FIG. 1, the network 1 is labeled A to G.
7 and the seven links a to g connecting the routers. The numbers assigned to the links a to g are the costs set for the links. For example, it is assumed that the cost of the link a is “1” and the cost of the link d is “2”.

In the network 1 shown in FIG. 1, O
When routing is performed by SPF, Router A to Router F
The route for data transmission to is the link a (cost =
The route (route 1) passing through 1), the router D, and the link f (cost = 1) has the smallest total cost (that is, “2”) of each link, and thus is determined as the optimum route. A route (route through another route (link d (cost = 2), router E, link e (cost = 2), router G, link g (cost = 2), router D, link f (cost = 1)) 2)) is not an optimum route because the total cost of the links passing through is “7”.

Similarly, the route for transmitting data from the router A to the router G passes through the link a (cost = 1), the router D, and the link g (cost = 2) (route 3).
However, since the total cost of each link (that is, “3”) is the smallest, it is determined as the optimum route. For the other routes (routes passing through the link d (cost = 2), the router E, and the link e (cost = 2) (referred to as route 4)), the total cost of the links passing through is “4”. It is not the optimum route.

That is, the route for data transmission from the router A to the router F and the router G is the route passing through the router D using the link a (route 1 and route 3 described above).
However, since the cost is the lowest, it is the optimum route for both routes.

Here, assuming that a request for data transmission to the router F and a request for data transmission to the router G are simultaneously issued to the router A, the router A sends these two data transmissions to the router A. Attempt to take the route via D (route 1 and route 3 described above). At this time, if the amount of data to be transmitted greatly exceeds the transmission capacity of the link a that connects the routers A and D, congestion will occur on the link a that connects the routers A and D. At this time, as the routes from the router A to the router F and the router G, there are routes passing through the router E, that is, the routes 2 and 4 described above, but these two routes are regarded as the optimal routes in OSPF. Therefore, data transmission to the router F and the router G is not performed using these two routes.

The present invention has been made to improve the situation described above, and an object of the present invention is to provide a method in which, in a network using OSPF as a routing protocol, when traffic is concentrated at a specific place in the network. Another object of the present invention is to provide a traffic distribution method and a traffic distribution method using the OSPF cost, which makes it possible to distribute traffic by automatically and temporarily increasing the cost of the link at the specific location.

[0012]

A traffic distribution system using OSPF cost of the present invention comprises a plurality of routers, each of which is a routing protocol of OSPF (Open Shortest Path F).
In the network using the (irst), each of the routers observes the transmission data amount of the transmission data transmitted from the link connecting the routers, and the transmission data amount of a certain link is set in advance. When the threshold is exceeded, the link cost preset for the link is automatically changed, the optimum route by the OSPF of the network is updated, and subsequent transmission data is transmitted to the updated optimum route. Thus, the link cost changing means for changing the amount of data transmitted from the link to distribute the traffic is provided.

Further, the link cost varying means includes a transmission data amount threshold value storage section for storing a transmission data amount threshold value indicating an upper limit of the transmission data amount to each link connected to the router, and each link of the network. Link cost storage unit that stores the cost of each link, a route table storage unit that stores a route table that indicates an optimal route in OSPF based on the cost of each link of the network, and each link stored in the link cost storage unit An optimum route in OSPF is calculated based on the cost, and a route table creation unit that creates the route table and stores it in the route table storage unit and the amount of data transmitted from each link connected to the router are observed. The data amount observation unit and the data amount observed by the data amount observation unit exceed the transmission data amount threshold stored in the transmission data amount threshold storage unit. The case, characterized by comprising a link cost resetting unit that performs control for increasing or decreasing the cost of the relevant links automatically, the.

Further, the link cost varying means further includes an input / output unit for inputting / outputting setting data to / from the transmission data amount threshold value storage unit and the link cost storage unit, and the transmission data from the router to the route. A transmission / reception unit that transmits to another router according to the table and receives transmission data from the other router.

Further, the routing table includes at least a column of a destination indicating a router which is a destination from the router, a column of a next router indicating a next router for data transmission to the destination, and a column of the destination. And a total cost column indicating the total cost of each link forming a route, and in the row direction of the route table, descriptions regarding all routers as destinations from the router are arranged. To do.

Further, in a network including a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router, and the current CPU usage rate is When the CPU utilization threshold value set in advance is exceeded, the link costs of all the links connected to the router are automatically changed to the OSP of the network.
A second link cost changing means for changing the optimum route using the router as a route to distribute traffic by updating the optimum route by F is characterized by being provided.

Further, the second link cost varying means stores a CPU usage rate storage unit for storing a CPU usage rate threshold indicating an upper limit of the CPU usage rate of the router, and a cost for each link of the network. OS based on the cost of the link cost storage unit and each link of the network
A routing table storage unit that stores a routing table indicating an optimal route in the PF, and an optimal route in the OSPF is calculated based on each link cost stored in the link cost storage unit to create the routing table and the routing table A route table creation unit to be stored in the storage unit and a CPU for observing the CPU usage rate of the router
Utilization rate observing section and C observed by the CPU utilization rate observing section
A control for automatically increasing or decreasing the costs of all links connected to the router when the PU usage rate exceeds the CPU usage rate threshold stored in the CPU usage rate storage unit. 2 link cost resetting section,
It is characterized by having.

Further, the second link cost changing means further includes a second input / output unit for inputting / outputting setting data to / from the CPU utilization rate storage unit and the link cost storage unit, and the router. And a transmission / reception unit that receives the transmission data from the other router while transmitting the transmission data of No. 1 to the other router according to the routing table.

In the routing table, at least a column of a destination indicating a router which is a destination from the router, a column of a next router indicating a next router for transmitting data to the destination, and a column for the destination. And a total cost column indicating the total cost of each link forming a route, and in the row direction of the route table, descriptions regarding all routers as destinations from the router are arranged. To do.

The traffic distribution method using the OSPF cost of the present invention includes a plurality of routers, and in a network in which each of the routers uses OSPF as a routing protocol, each of the routers is connected from a link connecting the routers. Observe the transmission data amount of the transmission data to be transmitted, and if the transmission data amount of a certain link exceeds the preset transmission data amount threshold, the link cost preset for the link is automatically Change
Updating the optimal route by OSPF of the network,
By transmitting the subsequent transmission data to the updated optimum route, the amount of transmission data from the link is changed to disperse the traffic.

Further, in a network including a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the amount of transmission data transmitted from each link connected to the router. (Step S1), it is determined whether the transmission data amount exceeds the transmission data amount threshold value of the corresponding link (step S2), and the transmission data amount transmitted from the corresponding link must exceed the transmission data amount threshold value. If (step S2
If nothing is done and the amount of transmission data transmitted from the corresponding link exceeds the transmission data amount threshold value (NO in step S2), the cost set for the corresponding link is higher than the current value. The value is reset to a lower value or a lower value (step S3), and the OSPF is based on the cost of each link after the change.
And the routing information is updated again (step S4).

Further, in a network having a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router, and the current CPU usage rate is When the CPU utilization threshold value set in advance is exceeded, the link costs of all the links connected to the router are automatically changed to the OSP of the network.
By updating the optimum route by F, the optimum route using the router as a route is changed to achieve traffic distribution.

In a network having a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router (step S6), It is determined whether the CPU usage rate exceeds a preset CPU usage rate threshold value (step S7), and if the current CPU usage rate does not exceed the CPU usage rate threshold value (YES in step S7), nothing is done. Do not do the current C
If the PU usage rate exceeds the CPU usage rate threshold value (NO in step S7), the link costs of all links connected to the router are reset to values higher or lower than the current values (step S7). S8), based on the cost of each link of the network after the change, the OSPF is rerouted to update the routing information (step S9).

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a network configuration diagram showing an embodiment of a network to which the traffic distribution system using the OSPF cost of the present invention is applied.

The network 1 of this embodiment shown in FIG.
Consists of seven routers, Router A, Router B, Router C, Router D, Router E, Router F, and Router G,
Between each router, link a between A and D, link b between A and B, link c between A and C, link d between A and E, E and G
It is assumed that they are connected to each other by seven links including a link e between them, a link f between D and F, and a link g between D and G. The numbers assigned to the links a to g are the costs set for the links. For example, it is assumed that the cost of the link a is “1” and the cost of the link d is “2”. In addition, in the network 1, it is assumed that routing is performed by the OSPF protocol.

Next, the configuration of each of the routers A to G in this embodiment will be described with reference to FIG.

FIG. 2 is a detailed block diagram showing an example of the router of this embodiment.

In FIG. 2, the router 10 is a router 10.
A transmission data amount threshold value storage unit 11 that stores a transmission data amount threshold value that indicates the upper limit of the transmission data amount to each link connected to the network, a link cost storage unit 12 that stores the cost of each link of the network 1, and a network. The routing table storage unit 13 stores a routing table indicating the optimal route in OSPF based on the cost of each link of 1.

The router 10 also has an input / output unit 15 for inputting / outputting setting data to / from the transmission data amount threshold storage unit 11 and the link cost storage unit 12, and each link cost stored in the link cost storage unit 12. Data for observing the amount of data transmitted from each link connected to the router 10 and the route table creating unit 16 that creates the route table by calculating the optimum route in OSPF based on When the data amount observing unit 17 and the data amount observed by the data amount observing unit 17 exceed the transmission data amount threshold stored in the transmission data amount threshold storage unit 11, control for automatically increasing the cost of the corresponding link is performed. Link cost resetting section 18
And a transmission / reception unit 19 for transmitting the transmission data from the router 10 to another router according to the route table and receiving the transmission data from the other router.

In this embodiment, the transmission data amount threshold value storage unit 11 stores the transmission data amount threshold value "10M".
(Mega) byte "is set,
It is assumed that the cost of each link of the network 1 shown in FIG. 1 is initially set in the link cost storage unit 12. Then, the route table in the route table storage unit 13 is initially created by the route table creating unit 16.

An example of the route table is shown in FIG. 3 as the route table of the router A.

FIG. 3 is a diagram showing an example of the initial routing table of the router A.

In FIG. 3, the original routing table 3 of router A
0 is a destination 31 indicating a router which is a destination from the router A.
Column, next router 32 column indicating the next router for data transmission to the destination 31, and total cost 33 column indicating the total cost of each link forming a route to the destination 31.
It consists of Then, in the original row direction of the routing table 30 of the router A, the destination of the router A, router B
(Line 41) to Router G (Line 46) are arranged.

The manner in which the original routing table 30 of the router A was created will be described below.

The routing table is created by the routing table creating unit 16 based on the cost of each link stored in the link cost storage unit 12 to perform routing by OSPF to determine the optimum route for each destination. It First, referring to the network 1 of FIG. 1, destination B, destination C, destination D,
Since there is only one data transmission route to the destination E, that route is determined as the optimum route, and as a result, the destination B (line 41) to destination E (line 44) in FIG. 3 are created. The cost of link b (cost = 1), link c (cost = 1), link a (cost = 1), and link d (cost = 2) are directly described in the column of total cost 33 in each row. .

Next, in the network 1 shown in FIG. 1, as a route for data transmission from the router A to the router F (destination F), the link a (cost = 1), the router D, and the link f (cost =) are used. Route 1 (route 1)
However, since the total cost of each link (that is, “2”) is the smallest, it is determined as the optimum route. Other routes (link d (cost = 2), router E, link e (cost = 2), router G, link g (cost =
2), the route (route 2) passing through the router D and the link f (cost = 1)) is not an optimum route because the total cost of the passing links is “7”.

Therefore, the optimum route to the destination F (line 45 in FIG. 3) is the route of link a, router D, and link f, the next router 32 column is "D", and the total cost 33
The column of becomes "2".

Similarly, from router A to router G (destination G)
As a route for data transmission to the route (route 3) passing through the link a (cost = 1), the router D, and the link g (cost = 2), the total cost of each link (that is, “3”). )) Is the smallest, so it is determined as the optimum route. For the other routes (routes passing through the link d (cost = 2), the router E, and the link e (cost = 2) (referred to as route 4)), the total cost of the links passing through is “4”. It is not the optimum route.

Therefore, the optimum route to the destination G (line 46 in FIG. 3) is the route of link a, router D, and link g, the next router 32 column is "D", and the total cost 33
The column of becomes "3".

Next, the operation of this embodiment will be described. First, the operation before carrying out the invention of this embodiment will be described.

In the network 1 of FIG. 1, the router B
It is assumed that a request for data transmission is made from router F to router F. The transmission data is first transmitted to the router A, and the router A
Then, according to the initial route table 30 of the router A shown in FIG. 3, the transmission data addressed to the router F is transmitted from the link a to the router D.
Send to. At the same time, assuming that a request for data transmission is issued from router C to router G, the transmission data is first transmitted to router A, and router A follows the original route table 30 of router A shown in FIG. , Try to transmit the transmission data addressed to the router G from the link a to the router D. As a result, the transmission data destined for the router F and the transmission data destined for the router G are concentrated on the link a, and when the total amount of transmission data from the link a greatly exceeds the transmission capacity of the link a, the link Congestion occurs in a. At this time, as a route from the router A to the router F and the router G in the network 1 of FIG. 1, there is a route passing through the router E using the link d, but this route is the optimum calculated by the OSPF. Since it is not a route, the traffic concentrated on the link a is not transmitted using the link d. That is, the congestion state of the link a is not resolved.

Next, the operation of this embodiment when the present invention is applied will be described in detail with reference to the flowchart of FIG.

FIG. 4 is a flow chart for explaining the operation of this embodiment. In the operation description of this embodiment, the operation of the router A will be described as an example.

In the network 1 shown in FIG. 1, the router A has links a, b, and
The amount of transmission data transmitted from c and d is observed by the data amount observation unit 17 (step S1 in FIG. 4).

In the network 1 of FIG. 1, the router B
It is assumed that a request for data transmission of 10 Mbytes is made from router F to router F. The transmission data of 10 Mbytes is first transmitted to the router A, and the router A transmits the transmission data of 10 Mbytes addressed to the router F from the link a to the router D according to the original route table 30 of the router A shown in FIG.
Send to. At this time, the amount of transmission data (10 Mbytes) transmitted from the link a is the data amount observation unit 17
The data amount observing unit 17 determines whether or not the transmission data amount is equal to or less than the transmission data amount threshold value (10 Mbytes) of the link a stored in the transmission data amount threshold value storage unit 11 ( Step S2 of FIG. 4).

The amount of transmission data transmitted from the link a is
If it is less than or equal to the transmission data amount threshold value (YE in step S2)
S) The data amount observing unit 17 does nothing, but in the present embodiment, as described above, the transmission data amount (1
0 Mbytes is the transmission data amount threshold value (10M
It is determined that it is not less than or equal to (byte)) (N in step S2
O), the data amount observing unit 17 notifies the link cost resetting unit 18 of this fact.

The link cost resetting unit 18 of the router A
The transmission data amount transmitted from link a exceeds (or is equal to) the transmission data amount threshold value set for link a.
Therefore, the cost set for the link a is reset to a value higher than the current value and is reset in the link cost storage unit 12 (step S3 in FIG. 4). here,
It is assumed that the cost of link a (current value = 1) is reset to a higher value (“3”), and the cost of link a is automatically changed from “1” to “3” by router A. , As network 1-1 in FIG.

FIG. 5 is a network configuration diagram after the cost of the link a of the network of FIG. 1 is changed. In the network 1-1 of FIG. 5, the cost of the link a of the network 1 of FIG. It is a figure which shows the set network block diagram.

The link cost resetting unit 18 of the router A changes the cost of the link in the network 1 as in the network 1-1, so that the link cost resetting unit 18 of the router A changes the link cost after the change. The cost
All other routers B to G are notified via the transmitting / receiving unit 19. Then, each of the routers A, B, and G is rerouted by the OSPF based on the changed link cost by the routing table creation unit 16 of the router, and based on the changed link cost of the network 1-1. The routing information is updated (step S4 in FIG. 4), and the updated routing information is stored in the routing table storage unit 13 as a routing table. FIG. 6 shows the route table after the router A is updated.

FIG. 6 is a diagram showing the route table after the router A is updated.

Route table 3 after updating router A in FIG.
Since the configuration of 0-1 is the same as the original routing table 30 of the router A shown in FIG. 3, the components corresponding to the components shown in FIG. 3 have the same reference numerals or symbols in FIG.
The description is omitted. Further, the method of creating the route table 30-1 after the router A is updated is exactly the same as the method described in FIG. 3, and therefore the detailed description of the method of creation will be omitted.

In FIG. 6, the value of the total cost 33 of the destination D (row 43) is updated to "3", and the value of the total cost 33 of the destination F (row 45) is "4". Has been updated to.

Further, the route to the destination G (the line of 46) is updated so as to pass through the router E (the next router 32 column of the line of 46), and the total cost 33 of the route is 33.
Has been updated to "4". Therefore, it can be seen that the optimum route from the router A to the router G has been updated to the route passing through the router E.

Here, assuming that a request for data transmission is made from the router C to the router G, the transmission data is first transmitted to the router A, and the router A sends the updated route of the router A shown in FIG. According to Table 30-1, the transmission data addressed to the router G is transmitted from the link d to the router E.

Therefore, the transmission data is not concentrated on any of the links a and d, no congestion occurs on any of the links, and as a result, traffic distribution is achieved.

In the present embodiment, when the amount of transmission data from each link observed by the data amount observing unit 17 becomes small, control for reducing the cost of the link is performed by the link cost resetting unit. By 18
The link cost shown in the network 1-1 can be returned to the link cost of the original network 1, and data can be transmitted by the route of the original network 1.

As described above in detail, according to the first embodiment of the present invention, the router automatically increases the cost of the link in which the traffic is concentrated, and the route calculation is performed again by OSPF. In this way, the route table can be re-created so that the route that uses another link will be the optimal route, and as a result, subsequent traffic will pass through the route of another link, thus distributing the traffic. The effect is that it can be achieved.

Next, referring to FIGS. 1 and 7 to 11,
A second embodiment of the present invention will be described.

In the second embodiment, the link traffic (transmission used in the first embodiment is used as a threshold for changing the cost of each link shown in the network 1 of FIG. 1 in order to disperse the traffic. Not the amount of data)
CPU (Central Process) of the router
g Unit: Central processing unit) The point of using the usage rate is
This is different from the first embodiment.

The network to which the traffic distribution method using the OSPF cost of the second embodiment is applied is shown in FIG.
The network 1 shown in FIG. 1 will be described, and the following description will be made with reference to FIG. 1 again.

Next, the configuration of each of the routers A to G in the second embodiment will be described with reference to FIG.

FIG. 7 is a detailed block diagram showing an example of the router of the second embodiment. Note that, in FIG. 7, components corresponding to those shown in FIG. 2 are designated by the same reference numerals or symbols, and detailed description thereof will be omitted.

In FIG. 7, the router 20 is the router 20.
A CPU usage rate threshold storage unit 21 that stores a CPU usage rate threshold value indicating an upper limit of its own CPU usage rate;
Link cost storage unit 12 that stores the cost of each link
And OSPF based on the cost of each link of network 1.
And a route table storage unit 13 for storing a route table showing the optimum route in. The link cost storage unit 12 and the route table storage unit 13 are equivalent to those in FIG.

The router 20 further includes an input / output unit 25 for inputting / outputting setting data to / from the CPU usage rate storage unit 21 and the link cost storage unit 12, and each link cost stored in the link cost storage unit 12. A route table creation unit 16 that calculates an optimal route in OSPF based on the above to create a route table and stores the route table in the route table storage unit 13, and a CP of the router 20 itself.
CPU usage rate observing unit 27 for observing U usage rate, and CPU
When the CPU usage rate observed by the usage rate observing unit 27 exceeds the CPU usage rate threshold value stored in the CPU usage rate threshold value storage unit 21, the costs of all the links connected to the router 20 are automatically calculated. A link cost resetting unit 28 for controlling the increase and a transmitting / receiving unit 19 for transmitting the transmission data from the router 20 to another router according to the route table and receiving the transmission data from the other router are provided. . The route table creating unit 16 and the transmitting / receiving unit 19 are the same as those in FIG.

In the second embodiment, the CPU
For example, "70%" is set as the CPU usage rate threshold in the usage rate storage unit 21, and the cost of each link of the network 1 shown in FIG. 1 is initially set in the link cost storage unit 12. It has been done. Then, the route table in the route table storage unit 13 is initially created by the route table creating unit 16.

An example of the route table is shown in FIG. 8 as the route table of the router E.

FIG. 8 is a diagram showing an example of the initial routing table of the router E.

In FIG. 8, the original routing table 5 of router E
0 is a destination 51 indicating a router which is a destination from the router E.
Column, a column for the next router 52 that indicates the next router for transmitting data to the destination 51, and a column for the total cost 53 that indicates the total cost of each link that is a route to the destination 51.
It consists of Then, in the row direction of the original route table 50 of the router E, the destination of the router E, the router A
(Line 61) to Router G (Line 66) are arranged. The original configuration of the routing table 50 of the router E and the method of creating the contents are the same as those of the routing table shown in FIG. 3, and therefore further description will be omitted.

Next, the operation of the second embodiment will be described. First, the operation before carrying out the invention of the second embodiment will be described.

Router B in network 1 of FIG.
From the router F to the router F, and from the router C to the router G to transmit the data. The transmission data from both routers B and C is first transmitted to the router A, and the router A transfers the transmission data to the other routers. At this time, if the amount of transmission data transferred by the router A becomes large, the CPU of the router A will be overloaded.

In this state, Router E to Router D
Assuming that a data transmission request is made to the destination, the router E transmits the transmission data to the router A according to the original routing table 50 of the router E shown in FIG. 8 (FIG. 8).
64 lines). However, the CPU of the router A is in an overloaded state due to the process of transmitting data addressed to the routers F and G, and the congestion of the CPU due to the addition of the process of transmitting data addressed to the router D.

Next, the operation of the second embodiment when the present invention is applied will be described in detail with reference to the flowchart of FIG.

FIG. 9 is a flow chart for explaining the operation of the router A of the second embodiment.

In the network 1 shown in FIG. 1, the router A observes the CPU usage rate of the router A itself by the CPU usage rate observing unit 27 (step S in FIG. 9).
6).

Router B in network 1 of FIG.
It is assumed that a request for data transmission from the router F to the router F and a request from router C to send the data to the router G are issued. The transmission data from both routers B and C is first transmitted to the router A, and the router A transfers the transmission data to the other routers. At this time, if the amount of transmission data transferred by the router A increases, the CPU of the router A is overloaded. Here, the router A sets its own CPU usage rate to C
Observed by the PU usage rate observing unit 27, the CPU usage rate observing unit 27 indicates that the current CPU usage rate is the CPU usage rate threshold value (7) stored in the CPU usage rate threshold value storage unit 21.
0%) or less is determined (step S in FIG. 9).
7).

If the current CPU usage rate is less than or equal to the CPU usage rate threshold value (YES in step S7), the CPU usage rate observing section 27 does nothing, but in the second embodiment, the router F is used as described above. Since the amount of data sent to and G is large and an excessive load is applied, it is determined that the current CPU usage rate (for example, 70%) is not lower than the CPU usage rate threshold value (70%) (NO in step S7), The CPU usage rate observing unit 27 notifies the link cost resetting unit 28 of this fact.

The link cost resetting unit 28 of the router A
Since the current CPU usage rate of router A exceeds (or is equal to) the CPU usage threshold value, the costs set for all links a, b, c, d connected to router A are higher than the current value. The value is reset to a high value and reset in the link cost storage unit 12 (step S8 in FIG. 9). Here, it is assumed that the cost of the links a, b, c, d is reset to a high value (“3”), and the cost of the links a, b, c, d is automatically changed to “3” by the router A. This network is shown as network 1-2 in FIG.

FIG. 10 is a network configuration diagram after the costs of the links a, b, c, d of the network of FIG. 1 are changed, and the network 1-2 in FIG. 10 is the links a, b of the network 1 of FIG. , C, d cost is "3"
FIG. 3 is a diagram showing a network configuration reset to FIG.

The link cost resetting unit 28 of the router A changes the cost of the link in the network 1 as in the network 1-2, so that the link cost resetting unit 28 of the router A changes the link cost after the change. The cost
All other routers B to G are notified via the transmitting / receiving unit 19. Then, each of the routers A, B, and G is rerouted by the OSPF based on the cost of the changed link by the routing table creating unit 16 of the router, and based on the link cost of the changed network 1-2. The routing information is updated (step S9 in FIG. 9), and the updated routing information is stored in the routing table storage unit 13 as a routing table. FIG. 11 shows the route table after the router E is updated.

FIG. 11 is a diagram showing a route table after the router E is updated.

Since the configuration of the route table 50-1 after the update of the router E in FIG. 11 is the same as the original route table 50 of the router E shown in FIG. 8, the components shown in FIG. Corresponding components are designated by the same reference numerals or symbols, and description thereof is omitted.

In FIG. 11, the route to the destination D (row 64) is updated so as to pass through the router G (column next router 52 in line 64), and the total cost in that route is set. The value of 53 has been updated to "4", and
The route to the destination F (line 65) is updated so as to pass through the router G (column next router 52 in line 65), and the value of the total cost 53 on that route becomes "5". Has been updated. Therefore, it can be seen that the optimum route from the router E to the router D has been updated to the route passing through the router G.

Here, assuming that a request for data transmission is made from the router E to the router D, the router E is shown in FIG.
According to the updated routing table 50-1 of the router E shown in FIG. 1, the transmission data addressed to the router D is transferred from the link e to the router G.
Send to.

Therefore, the transmission data is not concentrated in the router A, the congestion does not occur in the router A, and as a result, the traffic is distributed.

In the second embodiment, when the CPU usage rate observed by the CPU usage rate observing unit 27 decreases, control is performed to reduce the cost of all links connected to the router. Link cost resetting unit 28
By doing so, it is possible to restore the link cost shown in the network 1-2 to the link cost of the original network 1, and it is possible to perform data transmission by the route of the original network 1.

As described above in detail, according to the second embodiment of the present invention, the router automatically raises the cost of all links connected to the router where traffic is concentrated, By re-calculating the route by OSPF, the route table can be re-created so that the route using the other router becomes the optimal route, and as a result, the subsequent traffic passes through the route of the other router. As a result, it is possible to disperse the traffic.

[0088]

As described above, the OSPF of the present invention
The cost-based traffic distribution method and traffic distribution method allow a router to automatically and temporarily change the cost of a link associated with a specific location in a network when the traffic is concentrated at the specific location in the network. Since the route can be updated so that the route passing through the specified portion is not the optimum route, there is an effect that the traffic concentrated at the specific location can be automatically distributed.

[Brief description of drawings]

FIG. 1 is a network configuration diagram showing an embodiment of a network to which a traffic distribution method using OSPF cost of the present invention is applied.

FIG. 2 is a detailed block diagram showing an example of a router of this embodiment.

3 is a diagram showing an example of an initial routing table of router A. FIG.

FIG. 4 is a flowchart illustrating the operation of this embodiment.

5 is a network configuration diagram after the cost of the link a of the network of FIG. 1 is changed.

FIG. 6 is a diagram showing a route table after the router A is updated.

FIG. 7 is a detailed block diagram showing an example of a router according to a second exemplary embodiment.

8 is a diagram showing an example of an initial routing table of router E. FIG.

FIG. 9 is a flowchart illustrating an operation of router A according to the second exemplary embodiment.

10 is a link a, b, c, d of the network of FIG.
FIG. 3 is a network configuration diagram after the cost is changed.

FIG. 11 is a diagram showing a route table after the router E is updated.

[Explanation of symbols] A router B router C router D router E router F router G router a link b link c link d link e link f link g link 1 network 10 routers 11 Transmission data amount threshold storage unit 12 Link cost storage 13 Routing table storage 15 Input / output section 16 Routing Table Creation Department 17 Data amount observation section 18 Link cost resetting section 19 Transmitter / receiver 20 routers 21 CPU usage rate storage unit 25 Input / output section 27 CPU usage rate observation section 28 Link cost resetting section 30 Router A's original routing table 30-1 Router A's updated routing table 50 Router E's original routing table 50-1 Route table after updating Router E

Claims (12)

[Claims] 1. A plurality of routers are provided, and each of the routers uses OSPF (Open) as a routing protocol.
In a network using Shortest Path First, each of the routers observes the transmission data amount of the transmission data transmitted from the link connecting the routers, and the transmission data amount of a certain link is set in advance. When the data amount threshold is exceeded, the link cost preset for the link is automatically changed,
Updating the optimal route by OSPF of the network,
Traffic using an OSPF cost, characterized in that it comprises link cost varying means for varying the amount of transmission data from the link to distribute traffic by transmitting subsequent transmission data to the updated optimum path. Distributed method. 2. The link cost variable means, a transmission data amount threshold value storage unit for storing a transmission data amount threshold value indicating an upper limit of the transmission data amount to each link connected to the router, and each link of the network. Link cost storage unit that stores the cost of each link, a route table storage unit that stores a route table that indicates an optimal route in OSPF based on the cost of each link of the network, and each link stored in the link cost storage unit An optimum route in OSPF is calculated based on the cost, a route table is created by creating the route table and stored in the route table storage unit, and the amount of data transmitted from each link connected to the router is observed. When the data amount observation unit and the amount of data observed by the data amount observation unit exceed the transmission data amount threshold stored in the transmission data amount threshold storage unit The traffic distribution method using the OSPF cost according to claim 1, further comprising: a link cost resetting unit that performs control for automatically increasing or decreasing the cost of the corresponding link. 3. The link cost varying means further includes an input / output unit for inputting / outputting setting data to / from the transmission data amount threshold value storage unit and the link cost storage unit, and the transmission data from the router to the route. The transmitting / receiving unit for transmitting to another router according to the table and receiving the transmission data from the other router, the O according to claim 2.
Traffic distribution method using SPF cost. 4. The routing table includes at least a column of a destination indicating a router which is a destination from the router, a column of a next router indicating a next router for data transmission to the destination, and a column for the destination. And a total cost column indicating the total cost of each link forming a route, and in the row direction of the route table, descriptions regarding all routers as destinations from the router are arranged. The traffic distribution method using the OSPF cost according to claim 2 or 3. 5. In a network comprising a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router, and the current CPU usage rate is When the CPU utilization threshold value set in advance is exceeded, the link costs of all the links connected to the router are automatically changed to update the optimum route by the OSPF of the network. Traffic distribution by changing the optimal route with router as the second route
The link cost varying means of
Traffic distribution method using SPF cost. 6. The second link cost varying means stores a CPU utilization threshold storage unit that stores a CPU utilization threshold indicating an upper limit of the CPU utilization of the router, and a cost of each link of the network. A link cost storage unit,
A route table storage unit that stores a route table showing an optimal route in OSPF based on the cost of each link of the network, and an optimal route in OSPF is calculated based on each link cost stored in the link cost storage unit. A routing table creating unit that creates the routing table and stores it in the routing table storage unit; a CPU usage rate observing unit that observes the CPU usage rate of the router; and a CPU that the CPU usage rate observing unit observes
A second control for automatically increasing or decreasing the cost of all links connected to the router when the usage rate exceeds the CPU usage rate threshold stored in the CPU usage rate storage unit. 6. The traffic distribution method using the OSPF cost according to claim 5, further comprising: 7. The second link cost changing means further includes a second input / output unit for inputting / outputting setting data to / from the CPU usage rate threshold storage unit and the link cost storage unit.
7. The OSPF cost according to claim 6, further comprising: a transmission / reception unit that transmits the transmission data from the router to another router according to the routing table and receives the transmission data from the other router. Traffic distribution method used. 8. The routing table includes at least a column of a destination indicating a router which is a destination from the router, a column of a next router indicating a next router for data transmission to the destination, and a column for the destination. And a total cost column indicating the total cost of each link forming a route, and in the row direction of the route table, descriptions regarding all routers as destinations from the router are arranged. The traffic distribution method using the OSPF cost according to claim 6 or 7. 9. In a network comprising a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes a transmission data amount of transmission data transmitted from a link connecting the routers. However, when the transmission data amount of a certain link exceeds the preset transmission data amount threshold value, the link cost preset for the link is automatically changed, and the optimum route by the OSPF of the network is set. Is updated and the subsequent transmission data is transmitted to the updated optimum route to change the amount of transmission data from the link to achieve traffic distribution, and a traffic distribution method using OSPF cost. 10. In a network comprising a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the amount of transmission data transmitted from each link connected to the router. (Step S1), it is determined whether the transmission data amount exceeds the transmission data amount threshold value of the corresponding link (step S2), and the transmission data amount transmitted from the corresponding link must exceed the transmission data amount threshold value. If (YES in step S2), nothing is done, and if the transmission data amount transmitted from the corresponding link exceeds the transmission data amount threshold value (NO in step S2), the cost set for the corresponding link is currently set. The value is reset to a value higher or lower than the value (step S3), and OSPF is used to reroute based on the cost of each link after the change. A traffic distribution method using an OSPF cost, characterized in that the routing information is updated by performing the update (step S4). 11. In a network comprising a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router, and the current CPU usage rate is When the CPU utilization threshold value set in advance is exceeded, the link costs of all the links connected to the router are automatically changed to update the optimum route by the OSPF of the network. A traffic distribution method using OSPF cost, characterized in that an optimum path having a router as a path is changed to distribute traffic. 12. In a network comprising a plurality of routers, each of which uses OSPF as a routing protocol, each of the routers observes the CPU usage rate of its own router (step S6), It is determined whether the CPU usage rate exceeds a preset CPU usage rate threshold value (step S7), and if the current CPU usage rate does not exceed the CPU usage rate threshold value (YES in step S7), nothing is done. Do not do the current CP
If the U usage rate exceeds the CPU usage rate threshold value (NO in step S7), the link costs of all links connected to the router are reset to values higher or lower than the current value (step S7). S8), based on the cost of each link of the network after the change, the OSPF is rerouted to update the routing information (step S).
9), A traffic distribution method using OSPF cost characterized by the above.