JP2014023050A - Method and apparatus for setting monitoring path for defective link identification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set, with a little computational amount, a route of a monitoring path group capable of accurately identifying another single link failure which occurs while any arbitrary single link is maintained, with a little monitoring paths.SOLUTION: A monitoring path determination section 21 comprises: a reference combination graph reading part 201 for reading a reference combination graph satisfying a restriction condition capable of all other single link failures which may occur while any arbitrary single link is maintained; a combination graph expanding part 202 and a correspondent combination graph extracting part 204 for generating a correspondent combination graph by successively expanding the reference combination graph under the restriction condition until the number of virtual links reaches at least the number of real links of a network; and monitoring route determining means 205 for determining a monitoring path group based on the correspondent combination graph.

Description

  The present invention relates to a monitoring path setting method and apparatus for a faulty link identification system, and particularly occurs during maintenance of an arbitrary single link using a combination graph simulating a real network to be monitored. The present invention relates to a monitoring path setting method and apparatus for setting, with a small amount of calculation, a monitoring path that can identify all other single link failure occurrence points.

  The location where a single link failure has occurred in the network to be monitored can be identified by setting a plurality of monitoring paths in the network and counting the communication states obtained by sending and receiving test packets on each monitoring path.

  In Patent Document 1, in a quality monitoring apparatus that terminates a monitoring path in a network, when quality degradation of a monitoring path is detected, the failure monitoring apparatus commonly passes the monitoring path in which the quality degradation is detected. A technique for estimating a link to be a failed link is disclosed.

  In Patent Document 2, by using a combination graph representing a set of monitoring paths that pass through each link of the monitoring target network, it is easy to route the path of the monitoring path group that can identify all single link failures and double link failures. Techniques for determining the above are disclosed.

Japanese Patent No. 3885931 Japanese Patent Application No. 2011-258854

  In Patent Document 1, it is difficult from the viewpoint of calculation amount to calculate a route of a monitoring path group that can accurately identify all link failures to be monitored.

  In Patent Document 2, when it is sufficient to specify only other single link failures that occur while maintaining an arbitrary single link, the number of monitoring paths to be set increases more than necessary.

  The object of the present invention is to solve the above-mentioned problems of the prior art, and to monitor other single link failures that occur while maintaining any single link with a small number of monitoring paths. It is an object of the present invention to provide a monitoring path setting method and apparatus for a faulty link identification system capable of setting a path of a path group with a small amount of calculation.

  In order to achieve the above object, according to the present invention, a plurality of quality monitoring devices having at least one of a monitoring data transmission function and a reception function are connected to some nodes on a network and received from the transmission function. In the monitoring path setting device of the fault link identification system that sends the monitoring data to the function through multiple monitoring paths and identifies the fault link based on the reachability, the monitoring path is represented by a virtual node. There is provided a failure management apparatus for setting a monitoring path group based on a combination graph in which a real link through which a path passes is represented by a virtual link connecting the virtual nodes.

  The failure management device includes a reference combination graph reading unit that reads a level 0 reference combination graph that satisfies a constraint that can identify all other single link failures that may occur during maintenance of any single link, and a reference Combination graph expansion means for generating a corresponding combination graph by sequentially expanding the combination graph under the constraint conditions until the number of virtual links reaches at least the number of actual links of the network, and for monitoring based on the corresponding combination graph Monitoring route determining means for determining a path group.

  According to the present invention, the following effects are achieved.

  (1) Routes of a small number of monitoring paths that can identify all other single link failure locations that can occur while maintaining any single link with a small monitoring traffic load Can be set with a small amount of calculation.

  (2) The combination of monitoring paths passing through each virtual link that can identify all other single link failures that may occur while maintaining any single link is automatically determined.

  (3) It is possible to immediately indicate a combination of monitoring paths that pass through each virtual link for a monitoring target network of an arbitrary scale.

  (4) The route of the minimum monitoring path group in which continuity on the monitored network is guaranteed while the monitoring traffic load on each link is kept small is shown.

1 is a block diagram showing a network configuration to which a monitoring path setting method and apparatus of the present invention are applied. 3 is a block diagram showing a configuration of a main part of a failure management device 2. FIG. It is the flowchart which showed the outline | summary of the process sequence of one Embodiment of this invention. It is the figure which showed the structure procedure of the combination graph which satisfy | fills constraint conditions. It is a schematic diagram for demonstrating a constraint condition. It is the figure which showed an example of the real network NW to be monitored, and its combination graph. It is the figure which showed an example of the initial stage combination table. It is the flowchart which showed the procedure which produces the last combination table from an initial combination table. It is the figure which showed the method of producing the last combination table from an initial combination table. It is the figure which displayed as a list the mode that the number of path segments changed in each monitoring path. It is the figure which showed an example of the last combination table | surface.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a network configuration to which a monitoring path setting method and apparatus for a faulty link identification system according to the present invention is applied. A real network NW to be monitored includes a number of node devices n, It is composed of a number of links that connect the node devices n to each other.

  In the present invention, a plurality of quality monitoring devices 1 having at least one of a monitoring data transmission function (t) and a reception function (r) are connected to an arbitrary node device n, and the quality having a transmission function is provided. A monitoring path is set from the monitoring device 1 (t) to the quality monitoring device 1 (r) having a reception function. In the present embodiment, it is assumed that all the quality monitoring devices 1 have both a monitoring data transmission function (r) and a reception function (r).

  The failure management apparatus 2 instructs each quality monitoring apparatus 1 (t) having a monitoring data transmission function (t) to set a monitoring path and transmit monitoring data through the monitoring path. The quality monitoring device 1 (r) having the monitoring data receiving function monitors the quality of the monitoring data received through the monitoring path, and notifies the failure management device 2 when quality deterioration is detected. The failure management device 2 identifies a failure link from the monitoring path information in which quality degradation is detected and the monitoring path route information regarding the link through which each monitoring path passes.

  Thereby, compared with the case where the quality monitoring apparatus 1 is provided for every link, the required number of quality monitoring apparatuses can be reduced. The failure management device 2 can be realized by a computer on which an input / output interface for communicating with each quality monitoring device 1 on the actual network NW and its application are installed.

  In the present invention, even if an arbitrary single link is under maintenance, a monitoring path group that can identify all other single link failure locations is set by route calculation in the failure management apparatus 2. The That is, in the present invention, there are a small number of monitoring paths that can reduce the monitoring traffic load to identify all other single link failures that may occur while maintaining any single link. It is set by using a combination graph described later.

  FIG. 2 is a block diagram showing the configuration of the main part of the failure management device 2. From the monitoring path setting unit 21 for setting a plurality of monitoring paths (monitoring path group) and each quality monitoring device 1. A link failure identifying unit 22 that identifies the failed link by transmitting monitoring data to each monitoring path.

  The link failure identification unit 22 transmits monitoring data from each quality monitoring device 1 (t) to the set plurality of monitoring paths, and the monitoring data does not reach the quality monitoring device 1 (r). And the monitoring data arrives very slowly, or it has been determined that a failure has occurred on a route with a very high error rate of the arrived monitoring data, and the failure monitoring path has passed and a failure has occurred. A link that does not pass a monitoring path that has not been identified is identified as a failed link.

  In the monitoring path setting unit 21, a reference combination graph reading unit 201 reads a level 0 reference combination graph described later from a storage device or an input interface (both not shown). The combination graph extension unit 202 converts the reference combination graph into a combination graph that can simulate a real network to be monitored, and all other single link failures that may occur while maintaining any single link. It is sufficiently expanded until the number of virtual links reaches at least the number of real links in the network under a predetermined constraint condition that realizes “can be specified”.

  The topology acquisition unit 203 acquires the physical real topology of the monitoring target network NW. The corresponding combination graph acquisition unit 204 extracts a part (partial combination graph) having the same number of links as the actual network NW from the expanded combination graph as a corresponding combination graph that simulates the actual network NW. An initial combination table representing the correspondence relationship between each real link, each virtual link of the correspondence combination graph, the monitoring path passing through each link, and the monitoring path segment constituting each monitoring path is created.

  As will be described in detail later, the monitoring path determination unit 205 is configured such that a large number of monitoring path segments constituting each monitoring path, which are provisionally defined in the initial combination table, are consecutive to each other. Then, the final combination table is created by manipulating the initial combination table so that each path segment length becomes longer by being aggregated into a smaller number, and a plurality of monitoring paths defined in the final combination table A segment is newly determined as a monitoring path group and notified to the link failure identification unit 22.

  FIG. 3 is a flowchart showing an outline of a processing procedure according to an embodiment of the present invention, and details thereof will be described later.

  In step S1, regarding the monitoring path group that can identify all other single link failures even if an arbitrary single link is under maintenance, disregarding the continuity of each monitoring path on the real network, A combination graph representing a monitoring path set passing through each virtual link is constructed. However, a link to which a passing monitoring path group is assigned in a state where the continuity of each monitoring path on the network is not guaranteed is expressed as a virtual link here.

  In step S2, a partial graph is extracted from the combination graph configured in step S1 based on the number of links constituting the monitoring target network, and an initial combination table representing a monitoring path set passing through each virtual link is created.

  In step S3, as will be described in detail later, the continuity of all the monitoring paths is ensured by exchanging the passing monitoring path set between two randomly selected virtual links. Thus, the final combination table representing the monitoring path group passing through each link is derived, and the route of the monitoring path group is determined.

  The present invention includes the above-described procedures, so that even if a single link is under maintenance, all other single link failures can be identified and the monitoring traffic load can be reduced. It is possible to determine the path of the use path group with a small amount of calculation.

  Next, each of the above procedures will be described in detail. In step S1, a combination graph representing a set of monitoring paths that pass through each virtual link is configured according to the following procedure. However, in this embodiment, in order to suppress the monitoring traffic load on each link, the number of monitoring paths passing through each virtual link is limited to two. Further, in the combination graph, each monitoring path is made to correspond to the vertex of the graph, and the virtual link is expressed by a solid line link connecting two vertices corresponding to two passing monitoring paths. A combination graph that satisfies the following constraints is constructed so that all single link failures that occur while maintaining any single link are identified by the monitoring path group.

  FIG. 4 is a diagram showing a configuration procedure of a combination graph that satisfies the constraint conditions. In this embodiment, a combination graph that includes three or less solid links and does not include a closed loop includes an arbitrary single link. This is a criterion for accurately identifying other single link failures that occur during maintenance, and this is a constraint in extending the combination graph to the assumed real network scale.

  In this embodiment, as shown in FIG. 5A, the level 0 combination graph is composed of four vertices MP and four virtual links VL, and each monitoring path is represented by each vertex MP. The virtual link VL connected to each vertex MP represents one real link through which the monitoring path represented by the vertex MP passes.

  In other words, as shown in FIG. 5A, when the combination graph is composed of three vertices MP and three virtual links VL, the virtual link VL1 is under maintenance (XX). When quality degradation occurs in the two monitoring paths MP2 and MP3, even if a fault (×) occurs in the virtual link VL3 and a new quality degradation occurs in the monitoring path MP1, this is not the case for the virtual link VL3. It cannot be distinguished whether it is caused by a failure or a failure of the virtual link VL2.

  On the other hand, as shown in FIG. 4 (a), when the combination graph is composed of four vertices MP and four virtual links VL, it is shown in FIGS. 5 (b) and 5 (c). As described above, when the virtual link VL1 is under maintenance (XX) and quality degradation has occurred in the two monitoring paths MP2 and MP3, a fault (X) further occurs in the virtual link VL4 [FIG. b)], quality degradation occurs only in the monitoring path MP1, while a failure occurs in the virtual link VL2 [Fig. (c)], quality degradation occurs only in the monitoring path MP4, and failure occurs in the virtual link VL3. If this occurs, quality degradation occurs in the monitoring paths MP1 and MP4, so that the location of the failure can be accurately identified.

  Returning to FIG. 4, FIG. 4B shows a level 1 combination graph obtained by expanding the level 0 combination graph by the combination graph expansion unit 202. A level 1 combination graph is composed of four level 0 combination graphs (# 1, # 2, # 3, # 4) and six level 0 graph connections that connect two of them together. .

  FIG. 2C shows the level 0 graph connection. The level 0 graph connection includes a total of eight virtual links VL1 to VL8. In FIG. 7B, only six virtual links connected to the top left vertex included in the level 0 graph connection are represented by dotted lines.

  FIG. 4D shows a combination graph of level i. Like the level 1 combination graph, the level i combination graph is composed of four level i-1 combination graphs and six level i-1 graph connections that connect two of them together. The

  FIG. 4E shows a level i-1 graph connection. A level i-1 graph connection includes a total of eight level i-2 graph connections. Based on such a configuration procedure, the level of the combination graph can be automatically raised, and a combination graph including a sufficiently large number of virtual links can be easily configured. Note that the number of vertices MP (i) and the number of virtual links VL (i) in the combination graph of level i are given by the following equations. However, GC (i-1) indicates the number of virtual links included in the i-1 level graph connection.

  In step S2, a combination graph including a number of virtual links equal to the number of links constituting the monitoring target network NW is extracted from the combination graph of sufficiently large scale configured in step S1 by the corresponding combination graph extraction unit 204. . At this time, by extracting a partial graph including only a combination graph of the lowest possible level, a combination in which the number of monitoring path groups corresponding to the number of links constituting the monitoring target network passes through each virtual link is obtained. From the extracted partial graph (corresponding combination gram), an initial combination table is generated that shows, in a tabular form, a set of monitoring paths that pass through each virtual link.

  More specifically, first, a sufficiently large scale combination graph is shown in tabular form. At this time, each row in the table corresponds to a virtual link, and each column corresponds to a monitoring path. The rows of the table are arranged from the top in the order in which the corresponding virtual links appear when expanding the combination graph. The columns of the table are arranged from the left in the order in which the corresponding monitoring paths appear when expanding the combination graph.

  Further, each column of the table assumes a value of “1” when the corresponding monitoring path passes through the corresponding virtual link, and “0” when it does not pass through. When the number of links L of the monitored network is VL (i-1) <L ≤ VL (i), L rows from the top and MP (i) columns from the left in the table created from a sufficiently large scale combination graph Take out. If there is a column whose values in all the columns are “0” on the right side of the extracted table, the column is deleted. As a result, an initial combination table indicating the combinations in which the number of monitoring path groups corresponding to the number of links constituting the monitoring target network passes through each virtual link is created.

  In the initial combination table, a virtual link and a real link that constitutes a real network to be monitored are arbitrarily associated. In the present invention, an initial combination table for an arbitrary monitored network can be created immediately by configuring a combination graph including a sufficiently large number of virtual links in advance.

  FIG. 6 shows an example of a real network NW [FIG. (A)] to be monitored and a combination graph [FIG. (B)] corresponding to the network NW.

  As shown in FIG. 2A, the real network NW is composed of eight nodes N and 16 real links. As shown in FIG. 4B, the corresponding combination graph includes 16 virtual links that are the same as the actual link number, and the number of vertices is 8, so the number of necessary monitoring paths is 8. Therefore, the initial combination table created from the corresponding combination graph is as shown in FIG.

  In the initial combination table of FIG. 7, correspondence between virtual links and real links, and correspondence between monitoring paths that pass through each link and path segments that constitute each monitoring path are registered. In this embodiment, “1” is written in the location of the link that should be passed by each monitoring path, and “0” is marked in the location of the link that should not pass. Therefore, for example, the monitoring path E passes through the four real links (2, 4), (2, 6), (3, 6), and (7, 8). However, although the actual links (2, 4), (2, 6), and (3, 6) are continuous, the actual links (7, 8) are independent. That is, the monitoring path E includes two path segments.

  As described above, referring to the initial combination table, the correspondence relationship between the actual links constituting the network and the virtual links in the combination graph, and the monitoring path group that should pass through each actual link are clarified.

  In step S3, the monitoring path determination unit 205 performs exchange of passing monitoring path sets between two randomly selected virtual links with the initial combination table of FIG. 7 as a starting point. In a state where the continuity of all the monitoring paths is guaranteed, a final combination table representing the monitoring path group passing through each link is derived to determine the path of the monitoring path group.

  FIG. 8 is a flowchart showing in detail the procedure of step S3. In step S21, the number of segments M0 of the monitoring paths that are continuous on the monitored network is counted in the initial combination table. In step S22, the exchange number counter that counts the exchange number C of the monitoring path set is reset. In step S23, two real links are selected at random. In step S24, the number of monitoring path segments M1 continuous on the monitoring target network when the monitoring path pairs passing through the two selected real links are exchanged is counted.

  For example, when two real links (2, 7) and (4, 5) are selected in step S23, in step S24, the monitoring path set [01000100] of the real link (2, 7) in the initial combination table. ] And the monitoring path set [00100010] of the actual link (4, 5) are exchanged. As a result, as shown in FIG. 9, the path segments change in the four monitoring paths B, C, F, and G.

  FIG. 10 is a diagram showing a list of changes in the number of path segments in each of the monitoring paths B, C, F, and G. In the monitoring path B, one continuous path segment [(1 , 2), (2,7), (7,1)] and one independent path segment (5,6) (Fig. (A)), but two consecutive path segments after replacement [(2,1), (1,7)] and [(4,5), (5,6)] [(b) in the figure], and the increase / decrease number is “± 0”.

  In the monitoring path C, there are three consecutive path segments [(8,1), (1,7)] and two independent path segments (2,6), (4,5) before replacement. [Figure (c)] becomes one continuous path segment [(8,1), (1,7), (7,2), (2,6)] after replacement [Figure (d) ], The increase / decrease number is “−2”.

  In the monitoring path F, one continuous path segment [(2,7), (7,4), (4,3), (3,6)] before replacement is [Fig. (E)] After that, one continuous path segment [(5,4), (4,3), (3,6)] and one independent path segment (4,7) become a total of two [figure (f) ], The increase / decrease number is “+1”. In this way, the pass segment group that cannot be written with one stroke in this embodiment is counted as a plurality of path segments that include a portion that can be stroked and a portion that cannot be stroked.

  In the monitoring path G, one continuous path segment [(3,8), (8,5), (5,4), (4,7)] before replacement is two consecutive paths after replacement. The segments are [(2,7), (7,4)] and [(3,8), (8,5)], and the increase / decrease number is “+1”. Therefore, in step S24, the change in the number of path segments due to the current monitoring path pair replacement is ± 0.

  In step S25, it is determined whether or not the number of path segments has decreased. Here, since it is determined that the value has not decreased, the process proceeds to step S26, and the count value is incremented. In step S27, it is determined whether or not the number of exchanges C has reached a predetermined threshold value Cth. If C <Cth, the process returns to step S23 and the above processes are repeated.

  On the other hand, if the number of path segments is decreased, the path segments are aggregated by the current exchange, so that the process proceeds to step S28, and the exchange is reflected in the initial combination table. In step S29, the count value is reset.

  In this embodiment, each path segment finally obtained by the above procedure is newly regarded as a monitoring path, so that the monitoring traffic load on each link is kept small, and the link of each link through which each monitoring path passes is kept. A monitoring path set passing through each link in a state where continuity is guaranteed is obtained.

  That is, the route of a small number of monitoring path groups that can identify all single link failures that may occur during maintenance of any single link and reduce the monitoring traffic load by the derived final combination table. Is determined.

  FIG. 11 is a diagram showing an example of the final combination table obtained through the above processing. Here, in order to ensure the continuity of each monitoring path, it is not necessary to increase the number of monitoring paths. The necessary number of monitoring paths is eight. The final combination table in FIG. 11 shows the route of the monitoring path group in the monitoring target network shown in FIG.

  DESCRIPTION OF SYMBOLS 1 ... Quality monitoring apparatus, 2 ... Fault management apparatus, 21 ... Monitoring route setting part, 22 ... Link fault specific | specification part, 201 ... Reference combination graph reading part, 202 ... Combination graph expansion part, 203 ... Topology acquisition part, 204 ... Correspondence Combination graph extraction unit, 205... Monitoring route determination unit

Claims (6)

A plurality of quality monitoring devices having at least one of a monitoring data transmission function and a reception function are connected to some nodes on the network, and the monitoring data is transmitted from the transmission function to the reception function through a plurality of monitoring paths. In the monitoring path setting device of the failed link identification system that identifies the failed link based on the reachability,
A failure management device configured to set a monitoring path group based on a combination graph in which a monitoring path is represented by a virtual node, and a real link through which each monitoring path passes is represented by a virtual link connecting the virtual nodes; ,
The failure management device is
A reference combination graph reading means for reading a level 0 reference combination graph satisfying a constraint that can identify all other single link failures that may occur during maintenance of any single link;
A combination graph expansion unit that sequentially expands the reference combination graph under the constraint conditions until the number of virtual links reaches at least the number of actual links of the network;
A monitoring path setting device for a fault link identification system, comprising: a monitoring path determination unit that determines a monitoring path group based on the correspondence combination graph.   In the combination graph, each monitoring path is associated with a vertex of the graph, and a virtual link corresponding to a link constituting the network is represented by a solid line link connecting the two vertices corresponding to the two monitoring paths passing therethrough. 2. The monitoring path setting device for a fault link identification system according to claim 1, wherein the constraint imposed on the combination graph does not include a closed circuit composed of three or less solid links.   In the initial combination table showing the correspondence relationship between each real link of the network, each virtual link of the correspondence combination graph, the monitoring path passing through each link, and the path segment constituting each of the monitoring paths, the monitoring route determination means For the monitoring path that passes between two randomly selected virtual links so that the path segments of each monitoring path are contiguous with each other so that the path segments are aggregated into a smaller number and the length of each path segment is longer. 3. The monitoring path setting device for a fault link identification system according to claim 1, wherein the path set is repeatedly exchanged, and each path segment after the exchange is determined as a monitoring path.   The combination graph expansion means constitutes a level 0 reference combination graph by a closed loop composed of four solid links, and connects four level 0 combination graphs and two of them to each other. A level 1 combination graph is formed by a 0 graph connection, the level 0 graph connection includes 8 virtual links, and for any i (i> 1), 4 level i-1 combination graphs and their A level i combination graph is composed of six level i-1 graph connections that connect two of them together, and the level i-1 graph connection includes eight level i-2 graph connections to automatically combine them. 4. The monitoring path setting device for a fault link identification system according to claim 1, wherein the scale of the graph is expanded.   5. The failure link identification system according to claim 4, wherein the combination graph expansion unit extracts, as the corresponding combination graph, a partial graph including only a lower level combination graph from the expanded combination graph. Monitoring path setting device. A plurality of quality monitoring devices having at least one of a monitoring data transmission function and a reception function are connected to some nodes on the network, and the monitoring data is transmitted from the transmission function to the reception function through a plurality of monitoring paths. In the monitoring path setting method of the failed link identification system that identifies the failed link based on the reachability,
A failure management procedure for setting a monitoring path group based on a combination graph in which a monitoring path is expressed by a virtual node, and a real link through which each monitoring path passes is expressed by a virtual link connecting the virtual nodes. ,
The fault management procedure comprises:
Level 0 reference combination graph that satisfies the constraints that can identify all other single link failures that can occur during the maintenance of any single link, the number of virtual links reaches at least the number of real links in the network A procedure for generating a corresponding combination graph by sequentially expanding under the constraint conditions,
And a procedure for determining a monitoring path group based on the correspondence combination graph.