JPH05130144A - Dynamic routing system - Google Patents

Abstract

PURPOSE:To decentralize a load by changing a cost of a line dynamically when the state of the line (e.g. traffic or the like) is changed in other case than a line fault and calculating again the cost of a route up to a destination node and selecting a route offering the lowest cost. CONSTITUTION:The system is provided with a link state database 5 storing the cost calculated from its own node 1 to other node 1 in response to a change in the cost due to a dynamic factor between the nodes 1. A route offering a lowest cost up to the node 1 to which data are to be sent is selected by referencing the link state database 5 and the data are sent to a node 1 located next to the route.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dynamic routing system for dynamically changing routes.

In recent years, a dynamic routing protocol used in OSI, TCP / IP, etc. (in order for a system to dynamically determine a route to reach by learning by exchanging route information between the systems). It is required that more optimal cost settings be enabled. Therefore, it is desired to determine the route with the lowest cost in consideration of the dynamic factor (traffic, etc.) in addition to the static factor of the dynamic routing protocol as in the past.

[0003]

2. Description of the Related Art Conventional dynamic routing protocols are
For example, systems A, B, C, as shown in FIG.
The cost of each route between Ds is determined in advance (for example, at the time of system design) only by a static factor (for example, the connection form), and the cost once determined is that the line goes down (the cost is ∞). Other than that, I could not change it.

[0004]

Therefore, the conventional dynamic routing protocol has a problem that the cost cannot be changed and the route is not switched except when the line goes down. On the other hand, what users are expecting from a dynamic routing protocol is that the route can be changed by finding the minimum cost due to a dynamic factor (for example, a factor defined by the user such as traffic) to balance the load. There is a thing.

According to the present invention, the cost is dynamically changed when the state of the line (for example, traffic) changes except when the line is down, and the cost is calculated up to each destination node based on this cost. The purpose is to switch to the route with the lowest cost and distribute the load.

[0006]

[Means for Solving the Problems] Means for solving the problems will be described with reference to FIG. In FIG. 1, node 1
Is for transmitting and receiving data via a line.

The line state detecting section 3 detects the state of the line between the nodes 1 (for example, traffic volume). The link state database 5 calculates and stores the cost from the own node 1 to each of the other nodes 1 in response to the change in the cost due to the dynamic factor between the nodes 1.

[0008]

According to the present invention, as shown in FIG. 1, in response to a change in cost due to a dynamic factor between the nodes 1, the cost from the own node 1 to each of the other nodes is calculated and the link state is calculated. The data is stored in the database 5, and by referring to this, the route that minimizes the cost to the node 1 to which the data is transmitted is selected, and the data is transmitted to the node 1 next to this route.

At this time, as a dynamic change in the cost between the nodes 1, the line state detection unit 3 detects the line state (for example, traffic volume), and changes the cost when the detected line state changes. , Own node 1 to each other node 1
The cost of the route up to is recalculated and stored in the link state database 5, and the data is sent out to the node 1 next to the route with the minimum cost by referring to this. Further, when the cost between nodes is dynamically changed, all the other nodes 1 are notified, and the calculated cost from the own node 1 to each of the other nodes 1 is stored in the link state database 5. With reference to, a route that minimizes the cost to the node 1 to which data is transmitted is selected and the data is transmitted to the adjacent node 1.

Therefore, when the cost (for example, traffic) on the route changes other than when the line is down, the cost is dynamically recalculated and the route with the lowest cost is automatically switched to balance the load. It becomes possible.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the construction and operation of an embodiment of the present invention will be described in detail with reference to FIGS.

FIG. 1 shows a block diagram of an embodiment of the present invention.
FIG. 1A shows a configuration diagram. In (a) of FIG. 1, a node 1 transmits / receives data via a line, and includes a receiving unit 2, a line state detecting unit 3, an updating unit 4, a link state database 5, a route determining unit 6, and a transmitting unit. The database 7 and the transmission unit 8 are included.

The receiving unit 2 receives data from another adjacent node (system) 1. The line state detection unit 3 determines the line state of a link (line) between another node 1 adjacent to itself and its own node 1, for example, the traffic amount per unit time, that is, the data passage amount per unit time (for example, a frame). (Number / second) etc. are detected.

The update unit 4 updates the link state database 5 when the change in traffic volume exceeds a certain value and the cost needs to be updated. For example, the cost from the own node 1 to each of the other nodes 1 is recalculated and the cost in the link state database 5 is updated.

The link status database 5 is the self-node 1
For all other nodes 1 with which
It stores the costs of all the routes to reach the node 1 (see (a) and (c) of FIG. 2).

The route determination unit 6 refers to the link state database 5 to determine which route is selected for the node 1 with which communication is to be performed (the route with the minimum total cost is selected).

The transmission database 7 registers, for all routes 1 with which communication is possible, to which adjacent node 1 the data should be transmitted next when the data addressed to that node is received. (See (b) and (d) of FIG. 2).

The transmission unit 8 is for transmitting data to another adjacent node 1. 1B shows a network configuration diagram. Here, it is assumed that the network is composed of four nodes A, B, C, and D and are connected in a link shape as shown in the figure.
Here, ab = 1, bc = 2, cd = 2, and ad = 6 are costs between the nodes in the initial state (determined at the time of system design). Here, the cost is arbitrarily defined by the user, and is traffic throughput as an example. Therefore, the cost ab = 1 between a certain node 1 and a node 1, for example, a node A and a node B is changed to ab = 3 when the traffic exceeds a certain value. Along with this, the link status database 5 and the transmission database 7 are updated as shown in (c) and (d) of FIG.

First, the operation of the configuration of FIG. 1A will be described in the order from. In (a) of FIG. 1, the line state detection unit 3 detects the data amount per unit time of the data between the own node 1 and another adjacent node 1 every predetermined time, and sets it to a preset constant value. When the change amount becomes larger than the value, the update unit 4 is instructed to update the link state database 5.

The update unit 4 which has received the update instruction of the link state database 5 redetermines the cost between the nodes when the traffic amount changes, for example, (B) in FIG.
When the traffic between the nodes A and B becomes high, the cost ab = 1 is changed (increased) to the cost ab = 3, and as shown in (c) of FIG. The cost with all other nodes 1 is recalculated and the link state database 5 is updated (see (c) of FIG. 2).

[0021] informs the route determining unit 6 that the link state database 5 has been updated by the updating unit 4. Is referred to, the route determination unit 6 refers to the updated link state database 5 and redetermines the optimal route to all other nodes 1 (for example, the route with the minimum total cost), and transmits it. It is set in the database 7 (see (d) in FIG. 2).

The updating unit 4 instructs the transmitting unit 8 to notify the other nodes 1 that the link state database 5 has been updated. Notifies all the other nodes 1 of information such as the result of the update of the link state database 5 by the transmission unit 8 which has received the instruction. The other nodes 1 that have received this notification perform the update process in the same manner as from.

As described above, when the change in the traffic volume between a certain node 1 and the adjacent node 1 exceeds a preset constant value, the cost between the own node and each of the other nodes 1 is recalculated. Update the link state database 5 and select the route with the lowest cost to register the node that transmits the next data in the transmission database 7, and update the link state database 5 with the results of all other nodes 1.
To prompt the update of the link state database 5 of each node 1. As a result, the cost is dynamically changed when the change in the traffic volume exceeds a preset constant value, and the cost is recalculated corresponding to the change in the link state database 5 and the transmission database 7 of each node 1. It is possible to change dynamically, and it is also possible to notify the other nodes 1 and make similar changes.

Using FIG. 2, the cost ab = 1 between the node A and the node B in the network configuration diagram of FIG. 1B.
However, since the change in traffic volume exceeds a certain value, the cost ab =
The operation when the number becomes 3 will be specifically described.

2A and 2B are the initial cost (ab = 1, bc = 2, cd = 2, a) of FIG. 1B.
Calculation examples and values of the link state database 5 and the transmission database 7 when d = 6) are shown.

FIG. 2A shows an example of the link state database in the initial state. Here, the cost of node B is
When the route is B, the cost is ab = 1, and the route is D
When CB, cost ad = 6 + cost cd = 2 + cost bc = 2 = cost 10.

Similarly, the costs are calculated for all the routes to the nodes C and D as shown in the figure.
FIG. 2B shows an example of the transmission database in the initial state. Here, the node that transmits data next by the route to the node B is the node B. This is because the route: B having the lowest cost is selected from the costs of the route of the node B in the link state database 5 of FIG. It is determined and registered as the node B.

Similarly, for all the routes to the nodes C and D, the route with the lowest cost is selected with reference to the link state database 5 in FIG. Next, the adjacent node transmitting the data is registered in the transmission database 7 as shown in the figure.

Next, the node A and the node B in FIG.
2 (c) and (d) show the updated link state database and transmission database when the cost ab = 1 between and is changed to the cost ab = 3 due to the increase in traffic.

FIG. 2C shows an example of the updated link status database. Here, since the cost ab = 1 between the node A and the node B is changed to the cost ab = 3,
The cost of node B is the cost ab =
Update to 3.

Root: cost ad = 6 + for DCB
Cost cd = 2 + cost bc = 2 = cost 10,
It remains as it was. Similarly, if the costs are calculated for all the routes to the nodes C and D, it becomes as shown in the figure, and the costs enclosed by □ are updated.

FIG. 2D shows an example of the updated transmission database. Here, the node that transmits data next by the route to the node B is the node B, which remains unchanged.

On the other hand, the node which transmits data next by the route to the node D is the node D, and the route enclosed by □ of the node in FIG. 2C: BCD has the lowest cost. Correspondingly, the node transmitting the next data has been changed.

As described above, when the change in the traffic volume between a certain node 1 and the adjacent node 1 exceeds a preset constant value, the cost is changed to reduce the cost for the route 1 between all the nodes 1. Is recalculated and stored in the link state database 5, and the route with the lowest cost is selected and the node 1 that transmits data next to this route is registered in the transmission database 7 and updated. This makes it possible to dynamically change to an optimum route and transmit data when the change in traffic volume exceeds a certain value.

Next, the operation of the configuration of one embodiment of the present invention will be described in detail according to the order shown in the flowchart of FIG. In FIG. 3, S1 creates a link state database. For example, in the network configuration of FIG. 1B, as an initial state, as shown in FIG. 2A, the node A creates an initial state link state database.

At S2, a transmission database is created. This is, for example, in the case of the network configuration of FIG. 1B, as an initial state, as shown in FIG. 2B, the node A creates an initial state transmission database.

In step S3, traffic is detected. this is,
The traffic detection unit 3 in (a) of FIG. 1 detects the amount of data (traffic amount) per unit time at which data is transmitted and received between the own node 1 and another adjacent node 1.

In step S4, it is determined whether or not the change in the traffic amount detected in step S3 exceeds a certain value. In the case of YES, the traffic volume change exceeds a certain value, so S1,
S2 is executed to change the cost between the nodes, for example, to increase the value (for example, the value obtained by increasing the cost ab = 1 between the node A and the node B in (b) of FIG. 1 to the cost ab = 3). Initially, the costs of all routes between the own node 1 and all other nodes 1 are recalculated, for example, as shown in (c) of FIG. On the other hand, in the case of NO, since the traffic amount does not exceed a certain value, S3 is repeated.

As described above, each node 1 having the configuration shown in FIG. 1A detects the traffic volume between its own node 1 and another adjacent node 1, and the change in the traffic volume exceeds a certain value. Then, as shown in (c) and (d) of FIG. 2, the cost is changed (increased here) and recalculated, the route with the lowest cost is selected, and the node 1 that sends the next data is selected. To register. As a result, the route is dynamically changed in response to the change in traffic volume.

FIG. 4 shows a relay flow chart of the present invention. In FIG. 4, S11 receives data to be relayed. This is a node 1 having the configuration of (a) in FIG.
Receives data to be relayed (data as shown in the lower right) from another adjacent node 1.

S12 refers to the transmission database 7,
Send to the next node. This is done by extracting the destination of the data (packet) written on the right side received in S11, referring to the transmission database 7 (for example, refer to the transmission database 2 in FIG. 2B), and registered for the node 1 of the destination. Adjacent node 1 that is sending data next
Is taken out and data (packet) is transmitted to this node 1.

As described above, each node 1 refers to (b) or (d) transmission data base 7 in FIG.
The data is transmitted to the adjacent node 1 which is set in association with the destination. At this time, as described above, since the transmission database 7 is dynamically updated in response to the change in traffic volume, it is possible to transmit data to the route corresponding to this.

[0043]

As described above, according to the present invention,
When the line status (for example, traffic volume) changes, the line cost is dynamically changed, and the route to the destination node is re-costed and the route is sent to the route with the lowest cost. Since it is used, data can be automatically sent to a route with low cost even when the line is down. As a result, the load is dynamically and efficiently distributed when the state of the line changes between certain nodes, and it greatly contributes to the conventional network using the dynamic routing protocol.

[Brief description of drawings]

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

FIG. 2 is an example of a link status database / transmission database of the present invention.

FIG. 3 is a link status database / transmission database dynamic update flowchart of the present invention.

FIG. 4 is a relay flowchart of the present invention.

[Explanation of symbols]

 1: Nodes configuring network 2: Receiving unit 3: Line state detecting unit 4: Update unit 5: Link state database 6: Route determining unit 7: Transmission database 8: Transmission unit

Claims (3)

[Claims] 1. In a dynamic routing method for dynamically changing routes, in response to a change in cost due to a dynamic factor between nodes (1), each node is changed from its own node (1) to another node. (1)
A link state database (5) for storing the calculated costs up to, and referring to this link state database (5), selects a route that minimizes the cost to the node (1) that is going to transmit data. , A dynamic routing method characterized in that the data is sent to the node (1) next to this route. 2. When the node (1) is provided with a line state detecting section (3) for detecting the state of the line between the nodes (1), and when the line state obtained by the line state detecting section (3) changes. The dynamic routing system according to claim 1, wherein the cost between the nodes is dynamically changed. 3. When the cost between the nodes (1) is dynamically changed, all the other nodes (1) are notified, and from the own node (1) to each of the other nodes (1). 3. The dynamic routing system according to claim 1 or 2, wherein the calculated cost is stored in the link state database (5).