JP4190170B2 - Detour route setting system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a detour route setting system, and more particularly to a failure recovery system that switches to a detour route and restores a failure when a communication path fails, and a detour route design method for the failure recovery system.
[0002]
With the recent demand for higher reliability of communication paths, when a failure occurs, it is required to restore the failure as fast as possible. For this reason, various failure recovery systems are being studied. In addition, a detour route design method suitable for each failure recovery method is required.
[0003]
[Prior art]
When a failure occurs in a node or link in a network, the conventional detour route design system calculates a detour route for a link failure and a detour route for a node failure separately, and obtains a detour route based on the calculation result. It was.
[0004]
[Problems to be solved by the invention]
In the conventional detour route design for a node failure, a detour route for a path terminated at the fault node has not been calculated. However, since a node that detects a failure cannot immediately determine whether it is a link failure or a node failure, for example, when a node failure is detected when a link failure occurs, a path terminated at an adjacent node cannot be recovered. There was a problem.
[0005]
The present invention has been made in view of such a problem, and it is possible to design a detour route that can cope with either a node failure or a link failure, and to release an extra connection in the case of a node failure. It aims at providing the detour route setting system which can aim at the effective utilization to a resource by this.
[0006]
[Means for Solving the Problems]
(1) FIG. 1 is a principle block diagram of the present invention. In the figure, reference numeral 10 denotes a design system. In the design system 10, reference numeral 1 denotes a node failure handling bypass route design unit that designs a bypass route when a node failure occurs, and 2 denotes a link failure handling bypass route design unit that designs a bypass route when a link failure occurs. Reference numeral 3 is a detour path connection table provided by receiving the outputs of the node failure corresponding detour path designing unit 1 and the link failure corresponding detour path designing unit 2, and 4 is provided by receiving the output of the link failure corresponding detour path designing unit 2. It is a detour route release table.
[0007]
Reference numeral 20 denotes a network connected to the design system 10. The network 20 includes a plurality of nodes 21 and links 22. Each node is connected by a link. In the figure, N1 to N6 are shown as nodes, and L1 to L7 are shown as links. Then, a path is established between the nodes to transmit information. The number of nodes and the number of links are not limited to the illustrated example.
[0008]
The contents of the detour path connection table 3 and the detour path release table 4 of the design system 10 are copied to each node 21.
With this configuration, each node can automatically set a detour path according to the contents of the detour path connection table 3 when a node or link failure occurs in the network. Further, when a failure occurs in a node or a link, resources can be effectively used by releasing the connection of an extra link according to the contents of the detour route release table 4.
[0009]
(2) In the invention according to claim 2, the detour route connection table is a combination of the detour route information for the node failure and the detour route information for the link failure, and each node is provided with the detour route connection table. When detected, the fault location information is transferred and switched to a detour route according to the detour route connection table.
[0010]
With this configuration, it is possible to set a detour route according to the detour route connection table 3.
(3) In the invention according to claim 3, the detour path information only for the link failure is used as a detour path release table, each node has a detour path release table, and after switching by the fault recovery method according to claim 2, When it is determined that a node failure has occurred based on the transferred failure location information and topology information, the detour route is released according to the detour route release table.
[0011]
Here, the topology information refers to information indicating how the nodes are connected.
According to this configuration, the detour route can be released according to the detour route release table 4 to effectively use resources.
[0012]
(4) In the invention according to claim 4, a node that has determined that a node failure has transferred failure location information including failure node information to another node, and the node that has received the information releases a detour route According to the table, the detour route is released.
[0013]
With this configuration, the detour path can be released according to the detour path release table 4, so that resources can be effectively used.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 2 is a diagram for explaining the first operation of the present invention. The same components as those in FIG. 1 are denoted by the same reference numerals. In the following description, it is assumed that the contents of the detour path connection table 3 and the contents of the detour path release table 4 are copied to each node from the design system 10 in advance.
[0015]
Although the figure shows a case where N1 to N6 are provided as the node 21, it is not limited to this configuration. The link between N1 and N2 is L1, the link between N2 and N3 is L2, the link between N1 and N4 is L3, the link between N2 and N5 is L4, the link between N3 and N6 is L5, and between N4 and N5 The link is L6, and the link between N5 and N6 is L7. Further, a path extending between N4 and N6 is referred to as path 1, a path extending between N4 and N2 is referred to as path 2, and a path extending between N5 and N6 is referred to as path 3.
[0016]
In the system configured as described above, for example, a case where a failure (x mark) occurs in the node N5 and a detour path is designed is considered. In this case, calculation is made such that the detour route 1-N5 for the path 1 and the detour route 2-N5 for the path 2. The path 3 is terminated at the node N5, and in the case of the failure of the node N5, the detour path is not restored even if the detour path is designed. Therefore, the detour path is not normally calculated.
[0017]
FIG. 3 is a diagram illustrating a second operation of the present invention. The same components as those in FIG. 2 are denoted by the same reference numerals. This figure shows a case where a failure (x mark; the same applies hereinafter) occurs in the link L7. When designing a detour route in such a case, the detour route 1-L7 is calculated for the path 1, and the detour route 3-L7 is calculated for the path 3.
[0018]
However, the actual failure detection is performed at the node downstream of the signal. In the case of the failure of the node N5, the failure of the link L6 at the node N4, the failure of the link L4 at the node N2, and the failure of the link L7 at the node N6. It only looks like it is occurring. If the information detected in each is collected, it can be determined that there is a failure of the node N5.
[0019]
For example, in the node N6, the link L7 failure and the failure of the node N5 cannot be distinguished. Therefore, in order to design a detour route that can cope with both a link failure and a node failure, a detour route for a node failure may be calculated first, and then a detour route for a path terminated at the node may be calculated.
[0020]
For example, the detour paths for the path 1 and the path 3 affected by the link 7 failure of the node N6 are combined with the detour route 1-N5 calculated for the node failure and the detour route 3-L7 calculated for the link failure. It will be. FIG. 4 is a diagram illustrating the third operation of the present invention, and shows a case where the above-described detour paths 1-N5 and 3-L7 are set.
[0021]
FIG. 5 is a diagram for explaining the fourth operation of the present invention. Similarly, for the link L4 failure of the node N2, the detour route 2-N5 is set for the path 2 as shown in the figure. FIG. 6 is a diagram for explaining the fifth operation of the present invention, and shows a detour route for the failure of the path 2 and the path 1 with respect to the failure of the link L6 of the node N4. As shown in the figure, a case is shown in which detour routes 1-N5 and 2-N5 are set.
[0022]
Thus, according to the above embodiment, when a failure occurs in a node or a link in the network 20, each node can automatically set a detour path according to the contents of the detour path connection table 3. it can. Further, when a failure occurs in a node or a link, resources can be effectively used by releasing the connection of an extra link according to the contents of the detour route release table 4.
[0023]
FIG. 7 is a diagram showing the contents of the detour route connection table 3. The figure shows an example of the detour route connection table 3 in the node N3. For example, when a failure of the link L6 is detected at the node N4, it is indicated that the influence of the failure is avoided by connecting the channel 1 and the channel 2 corresponding to the detour path 1-N5 (see FIG. 6). ). Each of the links 22 is a bundle of a plurality of channels, and indicates which channel is connected to which channel and the failure is solved.
[0024]
If there is a failure in the link L7 of the node N6, the channel 1 and the channel 2 corresponding to the detour path 1-N5 and the channel 3 and the channel 4 corresponding to the detour path 3-L7 are connected. This is shown (see FIG. 4). In this way, a detour path can be set by connecting the link channels. Although the detour route connection table in the node N3 is shown in the figure, a similar connection table is provided and stored for each node. Therefore, it is possible to set a detour route when a failure occurs in any node.
[0025]
FIG. 8 is an explanatory diagram of the sixth operation of the present invention. As shown in the figure, when a failure is detected in the link L7 of the node N6, a failure recovery message is transferred from the node N6 to the node N3 by flooding (scattering messages). 30 in the figure is a failure recovery message. The failure recovery message includes a failure detection node and failure link information.
[0026]
The node that has received the failure recovery message transfers the message to the adjacent node again by flooding. Further, paths are connected according to the detour path connection table 3.
[0027]
According to this embodiment, a detour route can be set according to the detour route connection table 3.
FIG. 9 shows the contents of the detour route release table. This figure shows an example of a detour route release table in the node N3. When the failure node is N5, it indicates that channel 3 and channel 4 are released. Since the node N6 cannot instantly distinguish between the link L7 failure and the node N5 failure (see FIG. 3), the failure link information is transferred. For example, the node N3 also switches to the detour route 3-L7.
[0028]
However, when the failure is actually in the node N5, the switching of the detour path 3-L7 is useless, and the resource utilization efficiency is improved by releasing it. Therefore, each node has topology information as shown in FIG. FIG. 10 shows the relationship between the node number and the connection link information. For example, in the case of the node N1, the connected links are L1 and L3, and in the case of the node N2, the connected links are L1, L2, and L4. The same applies hereinafter.
[0029]
In the case of the node N5 failure, the link N7 failure information from the node N6, the link L4 failure information from the node N2, and the link L6 failure information from the node N4 are flooded (see FIG. 2). A node failure can be determined from these pieces of information and the topology information shown in FIG. For example, when the node N3 determines that the node N5 has failed, the connection between the channel 3 and the channel 4 corresponding to the detour route 3-L7 (see FIG. 3) is released according to the detour route release table 4 shown in FIG.
[0030]
According to this embodiment, it is possible to release a detour route according to the detour route release table 4 and to effectively use resources.
FIG. 11 is a diagram for explaining the seventh operation of the present invention. As described in the description of FIG. 9 and FIG. 10 described above, a node failure can be determined by combining information flooded from a node adjacent to the failed node. However, in order to prevent the message from being flooded indefinitely, there are cases where the number of nodes that have passed through the message (number of hops) is provided, and there is a restriction that no flooding occurs beyond a certain hop limit value.
[0031]
At this time, a message may not be received from all the nodes adjacent to the failed node, and the node failure may not be determined. In order to avoid this, the node that has determined the node failure transfers the failure location information including the failure node information to other nodes by flooding, and the node that has received this information releases the connection according to the detour route release table 4 .
[0032]
For example, in FIG. 11, it is assumed that the path 4 is set as shown in the figure, and the detour path 4-L7 is set as shown in the figure for the link L7 failure. Here, when the node N5 becomes a failure, the adjacent nodes N4, N2, and N6 detect the failure and start flooding respectively. If the hop limit value is 4, the message transmitted from the node N4 does not reach the node N8, and the node N8 cannot determine the node failure.
[0033]
However, the messages from the nodes N4 and N2 arrive at the node N6, and the failure of the node N5 can be determined. At this time, the node N6 transfers the message including the failed node information again by flooding, and the node N8 that has received the message releases the connection to the detour path 4-L7 according to the detour path release table 4.
[0034]
According to this embodiment, the detour route can be released according to the detour route release table 4, so that resources can be effectively used.
[0035]
【The invention's effect】
As described above, according to the present invention, the following effects can be obtained.
(1) According to the invention described in claim 1, with this configuration, when a failure occurs in a node or link in the network, each node automatically sets a detour route according to the contents of the detour route connection table 3. can do. In addition, when a failure occurs in a node or a link, resources can be effectively used by releasing the extra link connection according to the contents of the detour route release table.
[0036]
(2) According to the invention described in claim 2, it is possible to set a detour route according to the detour route connection table.
(3) According to the invention described in claim 3, according to the detour route release table, the detour route can be released to effectively use resources.
[0037]
(4) According to the invention described in claim 4, since the detour path can be released according to the detour path release table 4, it is possible to effectively use resources.
As described above, according to the present invention, it is possible to design a detour route that can cope with both a node failure and a link failure, and in the case of a node failure, it is possible to effectively use resources by releasing an extra connection. It is possible to provide a detour route setting system that can be realized.
[Brief description of the drawings]
FIG. 1 is a principle block diagram of the present invention.
FIG. 2 is a diagram illustrating a first operation of the present invention.
FIG. 3 is a diagram illustrating a second operation of the present invention.
FIG. 4 is a diagram illustrating a third operation of the present invention.
FIG. 5 is a diagram illustrating a fourth operation of the present invention.
FIG. 6 is an explanatory diagram of a fifth operation of the present invention.
FIG. 7 is a diagram showing the contents of a bypass route connection table.
FIG. 8 is an explanatory diagram of a sixth operation of the present invention.
FIG. 9 is a diagram showing the contents of a detour route release table.
FIG. 10 is a diagram illustrating a relationship between a node number and connection link information.
FIG. 11 is an explanatory diagram of a seventh operation of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Node failure response detour route design part 2 Link failure response detour route design part 3 Detour route connection table 4 Detour route release table 10 Design system 20 Network 21 Node 22 Link

Claims (4)

In a system where a design system and a network consisting of nodes and links are connected,
Within the design system,
A node failure handling detour route design unit that designs a detour route in the event of a node failure;
A link failure corresponding detour route design unit for designing a detour route at the time of link failure,
A detour route connection table provided by receiving the outputs of the detour route design unit corresponding to the node failure and the detour route design unit corresponding to the link failure,
A detour route release table provided in response to the output of the detour route design unit corresponding to the link failure,
First, a detour route for each node failure is calculated by the detour route design unit corresponding to the node failure, and then a detour route for the path terminated at the node is linked to the link failure connected to the node. The detour route setting system, wherein the contents of the detour route connection table and the detour route release table as a result of the calculation are copied to each node of the network. A combination of the detour route information for the node failure and the detour route information for the link failure is used as a detour route connection table. The detour route connection table is provided to each node, and when a failure is detected, the fault location information is transferred. 2. The detour route setting system according to claim 1, wherein the detour route connection system switches to a detour route according to the detour route connection table. The detour route information only for the link failure is used as a detour route release table, each node is provided with a detour route release table, and after switching by the failure recovery method according to claim 2, the node is determined by the transferred fault location information and topology information. 3. The detour route setting system according to claim 2, wherein, when it is determined that there is a failure, the detour route is released according to the detour route release table. The node that has determined that the node is faulty transfers the fault location information including the faulty node information to another node, and the node that has received the information releases the alternative route according to the alternative route release table. The detour route setting system according to claim 3.

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