JP2006279402A - Switching apparatus of communication route, method of switching communication route, and communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem wherein a long time is sometimes taken for finishing the route switching after a trouble happens in the conventional route switching system using a routing protocol. <P>SOLUTION: The communication route switching apparatus used in a communication network of communication routes by connecting a plurality of routers for communications comprises: a route controller for selecting a using communication route among a plurality of communication routes determined so as not to physically route the same router; a transmitter for transmitting signals to other apparatus connected to any of the plurality of communication routes; a receiver for receiving answer signals from the other apparatus for the signals; a monitor for monitoring the existence of troubles on the communication route according to the existence of reception of the answer signals; and a manager for selecting a using communication route among the plurality of communication routes, on the basis of the result of monitoring the existence of a trouble on the communication route by the monitor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a switching device for a communication path (hereinafter simply referred to as a route), and more particularly, to a switching device for a communication path in which a failure has occurred. The present invention relates to a communication path switching method, and more particularly to a communication path switching method in which a failure has occurred. The present invention relates to a communication system, and more particularly to a communication system capable of switching a communication path in which a failure has occurred.

  Conventionally, when a failure occurs in a network (hereinafter referred to as an IP network) using IP (Internet Protocol), a routing protocol such as RIP (Routing Information Protocol) or OSPF (Open Shortest Path First) is used. The communication path was switched by performing a process of bypassing the failure section on the network side.

  FIG. 11 is a conceptual diagram showing a conventional path switching method when a failure occurs. In FIG. 11, area A (101), area B (102), area C (103), and area D (104) are each one or more service node devices (not shown; simply referred to as nodes hereinafter) and one or more. Network including a path switching device (not shown). A node is a device that controls services such as voice calls, and provides services by performing packet communication with an opposite node. Each node belonging to the area A (101) is connected to the edge router 1 (105) of the IP network 109 via a route switching device in the own area A (101). The same applies to each node belonging to the region B (102), the region C (103), and the region D (104). The IP network 109 is a network that connects regions, and the region A (101), the edge router 2 (106), the edge router 3 (107), and the edge router 4 (108) are connected to the region A (101), It is connected to the region B (102), the region C (103), and the region D (104).

  When a failure occurs in a node belonging to each region, the failure is detected and resolved by a failure detection function or the like on the node side. A failure occurring in the IP network is detected by the IP network using a routing protocol, and the path is switched. Specifically, for example, when OSPF is used as a routing protocol, each router collects route information by exchanging Hello packets with an adjacent router, and switches the route based on this information.

  For example, Patent Document 1 discloses a technique in which quality detection means is arranged on the receiving side in communication such as an IP over WDM (Wavelength Division Multiplex) system. In the technique described in Patent Document 1, the quality detection unit provided on the receiving side receives the quality signal to monitor the quality of the transmission path or the quality of the signal passing through the transmission path. The quality signal includes (1) a signal in the transmission line, (2) a signal from a repeater in the transmission line, (3) monitoring information of the transmission line in the overhead area of the SONET frame, or (4) in the case of an optical fiber. An optical supervisory signal generated by an optical supervisory signal transmitter provided on the transmission side and wavelength-multiplexed with a packet signal and transmitted is disclosed. If the quality detection means provided on the receiving side detects a failure, the route control means of the packet switching device on the receiving side uses a different route from the route in which the failure is detected to send the occurrence of the failure to the transmitting side. To the packet switching device. Thereafter, the route control means of the transmission side packet switching device determines a detour.

JP 2000-92124 A

  In the conventional route switching method using the routing protocol in the IP network as described above, it may take a long time from the occurrence of a failure to the end of the route switching.

  In order to solve this problem, for example, it is conceivable that each node detects a failure in the IP network. However, this method is not practical because a high load is applied to both the IP network and each node.

  In the technique disclosed in Patent Document 1, since the quality detection unit is arranged on the reception side, the route control unit of the packet switching device on the reception side reports another failure to the packet switching device on the transmission side. Must be notified at. Therefore, when a failure has occurred in the notification route, the route control means of the packet switching device on the transmission side cannot know the occurrence of the failure, and there is a problem that the route cannot be switched.

  The object of the present invention is to solve this problem.

  That is, an object of the present invention is to monitor a path failure without imposing a large load on a node or an IP network. Alternatively, a high-quality communication is realized by switching from a failed communication path to a normal path at high speed. Alternatively, an object of the present invention is to reliably switch from a communication path in which a failure has occurred to a normal route even when a plurality of failures have occurred.

  The communication path switching apparatus according to the present invention is a communication path switching apparatus used in a communication network in which a communication path is configured by communication-connecting a plurality of routing apparatuses, and is determined not to pass through the physically same routing apparatus. A path control unit that selects a communication path to be used from among the plurality of communication paths, a transmission unit that transmits a signal to another device connected to any of the plurality of communication paths, and the signal A receiving unit that receives a response signal from the other device, a monitoring unit that monitors the presence or absence of the response signal, and a monitoring unit that monitors the presence or absence of the communication path. And a management unit that selects a communication path to be used from the plurality of communication paths based on the result.

  Alternatively, the signal and / or the response signal are both configured by a packet.

  Alternatively, the signal is transmitted periodically. Alternatively, the period is variable.

  Alternatively, the communication path is present on an IP network. Alternatively, the communication path is a label switched path. Alternatively, the communication path switching device, wherein the Label Switched Path communication path is realized by a multi-protocol label switching technique.

  The communication system of the present invention is a communication system in which a communication path is configured by communication-connecting a plurality of routing devices, and a plurality of communication routes determined so as not to physically pass through the same routing device, A first communication path switching device that selects a communication path to be used from a plurality of communication paths, and a second communication path switching device that is connected to any of the plurality of communication paths, The first communication path switching device transmits a signal to the second communication path switching device, and the first communication path switching device receives a response signal for the signal from the second communication path switching device. The communication path to be used is selected from the plurality of communication paths based on the result of monitoring the presence / absence of a failure in the communication path.

  In the communication path switching method of the present invention, in a communication network in which a communication path is configured by communicatively connecting a plurality of routing devices, the communication route switching method is selected from among a plurality of communication routes that are determined not to go through the same routing device physically. A communication path switching method for selecting a communication path to be used, wherein a transmission step of transmitting a signal to another apparatus existing on the communication path and a response signal from the other apparatus to the signal are received. There is a failure in the communication path as a result of monitoring the presence or absence of a failure in the communication path according to the reception step, the presence or absence of reception of the response signal, and the monitoring step in the monitoring step. And stopping the use of the communication path.

  In the communication path switching method of the present invention, in a communication system in which a communication path is configured by communication-connecting a plurality of routing devices, the communication route switching method is selected from among a plurality of communication routes that are determined not to pass through the same routing device physically. A communication path switching method for selecting a communication path to be used, wherein a first communication path switching device that selects a communication path to be used from among the plurality of communication paths is connected to one of the plurality of communication paths. Transmitting a signal to the second communication path switching device, and receiving a response signal from the second communication path switching device to the first communication path switching device; As a result of monitoring the presence or absence of a failure in the communication path based on the presence or absence of reception of the response signal, if there is a failure in the communication path, the step of stopping the use of the communication path, Characterized in that it.

  When the communication path switching apparatus of the present invention is installed between, for example, an edge router of an IP network and each node, the path switching at the time of path monitoring and failure detection is performed by this communication path switching apparatus. There is an advantage that the load applied to each node is small compared to the case of performing fault monitoring.

  In addition, the communication path switching device of the present invention detects a failure by a round trip of a failure monitoring signal. For this reason, according to the present invention, compared with the technique described in Patent Document 1, even when a plurality of failures occur on a round-trip route, it is possible to switch from a communication route in which a failure has occurred to a normal route. There is an advantage.

  The communication system according to the present invention employs the communication path switching device according to the present invention, so that a path failure can be monitored without applying a load to each node.

  Alternatively, the communication system of the present invention can switch from a communication path in which a failure has occurred to a normal path even when a plurality of failures have occurred on a round trip path.

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

Example 1
FIGS. 1 to 9 are conceptual diagrams showing a path switching method when a failure occurs in the communication system according to the first embodiment of the present invention.

  FIG. 1 is a conceptual diagram illustrating a state in which no failure has occurred in the present embodiment. In FIG. 1, a region A (201) includes a node A-1 (221), a node A-2 (222),. . . , The node A-x (223), and the path switching device 1 (210). Region B (202) includes node B-1 (224), node B-2 (225),. . . , Node B-x (226), and a network including the path switching device 2 (211). A maintenance terminal 298 and a maintenance terminal 299 for various settings are connected to the route switching device 1 (210) and the route switching device 2 (211), respectively. Each node belonging to the region A (201) is connected to the edge router 1-1 (205) and the edge router 1-2 (206) of the IP network 209 via the path switching device 1 (210). Each node belonging to the region B (202) is connected to the edge router 2-1 (207) and the edge router 2-2 (208) of the IP network 209 via the path switching device 2 (211). The IP network 209 is a network that connects regions, and the region A (201), the edge router 2-1 (207), and the edge router via the edge router 1-1 (205) and the edge router 1-2 (206). It is connected to the area B (202) via 2-2 (208). Between the edge router 1-1 (205) and the edge router 2-1 (207) and between the edge router 1-2 (206) and the edge router 2-2 (208), LSP (Label Switched) Path) communication path 1 (230) and LSP communication path 2 (231) are formed. The LSP communication path is a communication path in which the IP network is tunneled so that a plurality of paths logically provided in the IP network do not pass through the same physical device (router or the like). MPLS (Multi-Protocol Label) Switching) technology is used. In this embodiment, the LSP communication path 1 (230) is a primary or working communication path, and the LSP communication path 2 (231) is a secondary or backup communication path.

  The path switching device 1 (210) is located between the edge router 1-1 (205) and the edge router 1-2 (206) and each node (221, 222,..., 223). 221, 222,..., 223), the presence or absence of a failure on the communication path to the opposite area is monitored. The same applies to the route switching device 2 (211). That is, each node in each area (for example, node A-1 (221), node A-2 (222),..., Node A-x (223) in area A (201)) is in the IP network 209. The route switching device in each region (for example, the route switching device 1 (210) in the region A (201)) performs the failure monitoring as a representative. When a failure is detected, packet transmission is automatically switched to a communication path without a failure. FIG. 1 conceptually shows this state. In FIG. 1, the route switching device 1 (210) in the region A (210) transmits a failure monitoring packet 241 to the route switching device 2 (211) in the region B (211) through the primary LSP communication route 1 (230). ing. Further, the path switching device 1 (210) receives the failure monitoring response packet 242 from the path switching device 2 (211) through the primary LSP communication path 1 (230). Thereby, the path switching device 1 (210) detects the presence or absence of a failure on the primary LSP communication path 1 (230). Similarly, the route switching device 1 (210) in the region A (210) transmits a failure monitoring packet 243 to the route switching device 2 (211) in the region B (211) through the secondary LSP communication route 2 (231). Yes. Further, the path switching device 1 (210) receives the failure monitoring response packet 244 from the path switching device 2 (211) through the secondary LSP communication path 2 (231). Thereby, the path switching device 1 (210) detects the presence or absence of a failure on the secondary LSP communication path 2 (231). For example, ICMP (Internet Control Message Protocol) Echo Request can be used as the failure monitoring packet 241, the failure monitoring packet 243, the failure monitoring response packet 242, and the failure monitoring response packet 244.

  FIG. 2 is a conceptual diagram showing a state in which a failure has occurred in the present embodiment. In FIG. 2, a failure 301 has occurred on the return path as viewed from the path switching device 1 (210). Therefore, the failure monitoring response packet 242 of the primary LSP communication path 1 (230) does not reach the path switching apparatus 1 (210) in the area A (201), and the path switching apparatus 1 (210) is the primary LSP. It detects that a path failure has occurred in communication path 1 (230). In this case, when the path switching device 1 (210) transmits user data from each node in its own area A (201) to the area B (202), the area B (through the LSP communication path 2 (231), which is the secondary, 202), the route is switched so as to be transmitted to the route switching device 2 (211).

  FIG. 3 is a conceptual diagram showing a typical configuration of the path switching device. In FIG. 3, the path switching device 401 has a plurality of regional node device connection ports 402 and two IP network side connection ports 407, and has an interface with a maintenance terminal 410 for various settings. The regional node device connection port 402 includes node connection ports N-1, N-2, N-3,. . . , And Nx (403, 404, 405, ..., and 406). The IP network side connection port 407 includes a primary port I-1 (408) and a secondary port I-2 (409).

  FIG. 4 is a conceptual diagram showing a detailed internal configuration of the route switching device 401. 4A and 4B, the path switching device 401 includes a path control unit 501, a path information management unit 502, a packet reception unit 503, a path monitoring unit 504, and a packet transmission unit 505. Received by unit 503 and transmitted from packet transmitting unit 505. The maintenance terminal 410 mainly performs various settings for the route control unit 501. In FIG. 4A, the flow of a normal packet 507 that is not a failure monitoring packet is indicated by a thick arrow. In FIG. 4B, the flow of the failure monitoring response packet 508 and the failure monitoring packet 509 is indicated by thick arrows.

  Next, how the path switching apparatus shown in FIG. 4 realizes switching of communication paths as shown in FIGS. 1 and 2 will be described with reference to FIGS.

  FIG. 5 shows an example of a switching table that is referred to when the route information management unit 502 of the route switching apparatus 1 (210) installed in the area A answers an inquiry from the packet receiving unit 503. In FIG. 5, when the MAC address of the header indicates a node in the local area A (nodes A-1 to Ax), the route information management unit 502 does not rewrite the MAC address and transmits It is shown that the packet reception unit 503 is answered as ports N-1 to N-x. If the header MAC address is outside the local area (that is, the edge router I-1 or I-2), the route information management unit 502 refers to the transmission route management table (FIG. 6). It is shown that the packet reception unit 503 answers.

  An example of the transmission route management table of the route switching device 1 (210) installed in the area A is shown in FIG. FIG. 6 is a transmission path management table when there is a failure 301 on the primary LSP communication path 230 between the edge router 1-1 and the edge router 2-1. In FIG. 6, when the destination IP address is within the region B, even if the destination MAC address is that of the edge router 1-1, the route information management unit 502 assigns the destination MAC address to the edge router. It is shown that the packet reception unit 503 is replied to rewrite the packet to 1-2 and forward the packet to the port I-2 to which the edge router 1-2 is connected. If the destination IP address is in the region C (not shown in FIG. 2) or the region D (not shown in FIG. 2), the route information management unit 502 sets the destination MAC address. It is shown that the packet receiver 503 is replied to transfer the packet to the port I-1 without rewriting the edge router 1-1.

  An example of the 1 (210) route monitoring table of the route switching apparatus installed in the area A is shown in FIG. In FIG. 7, it is shown that an abnormality is detected because there is a failure 301 on the primary LSP communication path 230 between the edge router 1-1 and the edge router 2-1.

  The flowchart in FIG. 8 shows processing in the route control unit 501 in FIG. In FIG. 8, the route control unit 501 receives from the maintenance terminal 410 a route switching device (for example, the route switching device 2 (211) for the route switching device 1 (210) shown in FIGS. 1 and 2) facing the transmission route. Information such as the IP address, the transmission cycle of the failure monitoring packet for route monitoring, the threshold value of the number of hits for determining that there is a failure, whether to enable or disable the failure detection function is given (9-1) ). The route control unit 501 instructs the route monitoring unit 504 to start route monitoring (9-2). When the route monitoring unit 504 receives an instruction from the route control unit 501, the route monitoring unit 504 repeatedly transmits a failure monitoring packet 509 to the set IP address at a set cycle.

  When there is no failure in the communication path (for example, FIG. 1), the path monitoring unit 504 can receive a failure monitoring response packet (for example, 508) corresponding to the transmitted failure monitoring packet 509, and therefore can determine that there is no failure. For this reason, the route monitoring unit 504 repeatedly transmits the failure monitoring packet 509 to the set IP address until a failure occurs as shown in FIG. 2, for example.

  When a failure occurs in the communication path (for example, FIG. 2), the path monitoring unit 504 cannot receive a failure monitoring response packet (for example, 508) corresponding to the transmitted failure monitoring packet 509. When the failure monitoring response packet 509 cannot be continuously received for the set number of hits, the route monitoring unit 504 determines that a route failure has occurred and reports the occurrence of the route failure to the route control unit 501 (9− 2). The path control unit 501 determines whether the reported failure is a primary path (9-3). If the path failure has occurred in the secondary path, the process up to 9-6 in FIG. 8 is skipped, and the status of the path monitoring table (FIG. 7) is updated (9-7). If the path failure has occurred in the primary path, the path monitoring table (FIG. 7) is searched to determine whether the secondary path is normal (9-4). If an abnormality has occurred in the secondary route, the service is stopped, a device failure report is sent to the maintenance terminal 410 (9-5), and the process is terminated. When the secondary path is normal, the path information management unit 504 is instructed to rewrite the active path in the transmission path management table (FIG. 6) (9-6). Finally, the state of the route monitoring table (FIG. 7) is updated (9-7), and the process is terminated.

  The flowchart in FIG. 9 shows processing when the path switching device 401 receives a packet. 9, the packet receiving unit 503 is connected to each port (node connection ports N-1, N-2, N-3,..., And Nx (403, 404, 405,. 406) When receiving (10-1) a packet from the primary ports I-1 and I-2 (408 and 409)), the packet receiving unit 503 determines whether the packet is a failure monitoring response packet 508 or a normal packet 507. (10-2). If the packet is a failure monitoring response packet 508, the packet is transferred to the route monitoring unit 504 (10-3), and the process is terminated. If the packet is not the failure monitoring response packet 508, an inquiry is made to the route information management unit 502 as to whether the transmission port is the IP network side connection port 407 (10-4). The route information management unit 502 refers to the switching table (FIG. 5), and searches the transmission route management table when the transmission port is not the IP network side connection port 407 (when the transmission port is the regional node connection port 402). (10-5) is skipped. When the transmission port is the IP network side connection port 407, the route information management unit 502 searches the transmission route management table (FIG. 6) and determines which is the active route port (10-5). The packet receiving unit 503 rewrites the destination MAC address in the header with the one notified from the route information management unit 502, and transfers it to the packet transmitting unit 505 together with the transmission port information. The packet transmission unit 505 transmits the transferred packet to the transmission port (either the regional node connection port 402 or the IP network side connection port 407) (10-6). Further, the packet transmission unit 505 transmits the failure monitoring packet 509 instructed to be transmitted from the route monitoring unit 504 (10-6).

  As in the present embodiment, failure monitoring packets (241 and 243) and failure monitoring response packets (242 and 244) between the route switching device 1 (210) and the route switching device 2 (211) located outside the IP network 209 are used. ), The load on each node and the IP network 209 is suppressed.

  Also, in this embodiment, the primary communication path 230 and the secondary communication path 231 are prepared from the beginning instead of bypassing the failure path by the routing protocol in the IP network 209, and the failure monitoring packets (241 and 243) are periodically transmitted. Is sending to. For this reason, a failure can be detected in a short time, or when a failure is detected in the primary communication path 230, the communication can be restored by switching to the secondary communication path 231 in a short time.

  In this embodiment, each node (for example, nodes A-1, A-2,..., And Ax (221, 222,..., And 223)) and an edge router (for example, an edge) of the IP network 209 are used. Since the path switching device (for example, the path switching device 1 (210)) located between the routers 1-1 and 1-2 (205 and 206) is monitoring the communication path for failure, a failure is detected at each node. The route can be automatically switched without being conscious of.

Example 2
The conceptual diagram of the communication system which is the 2nd Example of this invention is shown in FIG. In this embodiment, the route switching device is further devised compared to the first embodiment. In FIG. 10, the description of the maintenance terminal of the path switching device is omitted.

  In FIG. 10, the difference from the first embodiment is as follows. For example, the route switching devices A-1, A-2,. . . , And A-x (1110, 1111,..., And 1112) are connected to the edge router 1105 and the edge router 1106, respectively. These route switching devices are connected to each node A-1, A-2,. . . , And Ax (1121, 1122,..., And 1123) are connected one-to-one.

  In this embodiment, unlike the first embodiment, each path switching device is connected to each node in the area on a one-to-one basis. Therefore, even if a failure occurs in any of the path switching devices, each node in the area All of this will not be disabled.

  As described above, the present invention has been described in each of the above embodiments, but the implementation of the present invention is not limited only to the configuration of each of the above embodiments. For example, in the first embodiment, the description has been given focusing on only two regions, region A (201) and region B (202), but other regions may exist, and all these regions may be present. It goes without saying that the present invention can be implemented without any problem. The same applies to the second embodiment. In the first embodiment, the path switching device (401 in FIG. 3) having two ports, the primary port I-1 (408) and the secondary port I-2 (409), as IP network side connection ports has been described. However, the number of IP network side connection ports of the path switching device is not necessarily limited to two, and a path switching device having an arbitrary number of ports is conceivable. The same applies to the node connection port of the path switching device. Each of the above embodiments has been described with respect to a network employing IP, but the implementation of the present invention is not limited to an IP network. A communication network in which a communication path is configured by communication connection of a plurality of routing devices is possible on a network employing various protocols. In each of the embodiments described above, the failure monitoring packet (241 or 243 in FIG. 1) has been described as being periodically transmitted. However, this cycle is not necessarily constant and may be changed. When the period is changed, there is an advantage that efficiency can be improved by appropriately changing the period depending on the reliability of the target communication path or the required communication quality. In the first embodiment, it has been described that the path switching device 1 (210) and the path switching device 2 (211) exist at both ends of the LSP communication path 1 (230) or the LSP communication path 2 (231). The path switching device is not necessarily present at both ends of the communication path, and may be present in the middle of the communication path. The same applies to the second embodiment. In the first embodiment, for example, the edge router 1-1 (205) and the edge router 1-2 (206) are connected to different ports of the path switching device 1 (210), but are connected to the same port. It doesn't matter. In this case, there is an advantage that the number of IP network side connection ports (for example, 407 in FIG. 3) of the path switching device can be reduced and the configuration of the path switching device (for example, 401 in FIG. 3) can be simplified.

It is a conceptual diagram which shows the state in which the failure has not generate | occur | produced in the communication system which is a 1st Example. It is a conceptual diagram which shows the state which the failure generate | occur | produced in the communication system which is a 1st Example. It is a conceptual diagram which shows the structure of the path | route switching apparatus in a 1st Example. It is a conceptual diagram which shows the detailed structure of the path | route switching apparatus in a 1st Example. It is a switching table of a path switching device. It is a transmission route management table of a route switching device. It is a path | route monitoring table of a path | route switching apparatus. It is a flowchart which shows the process in a route control part. It is a flowchart which shows the process at the time of a route switching apparatus receiving a packet. It is a conceptual diagram which shows the communication system which is a 2nd Example. It is a conceptual diagram which shows the path | route switching method (routing protocol use) at the time of the conventional fault occurrence.

Explanation of symbols

101 Region A
102 Region B
103 Region C
104 Region D
105 Edge router 1
106 Edge router 2
107 Edge router 3
108 Edge router 4
109 IP network 201 Region A
202 Region B
205 Edge router 1-1
206 Edge router 1-2
207 Edge router 2-1
208 Edge router 2-2
210 Route switching device 1
211 Route switching device 2
221 Node A-1
222 Node A-2
223 Node A-x
224 Node B-1
225 Node B-2
226 Node B-x
230 LSP communication path 1
231 LSP communication path 2
241 Failure monitoring packet 242 Failure monitoring response packet 243 Failure monitoring packet 244 Failure monitoring response packet 298 Maintenance terminal 299 Maintenance terminal 301 Failure 401 Path switching device 402 Regional node device connection port 403 Node connection port N-1
404 Node connection port N-2
405 Node connection port N-3
406 Node connection port N-x
407 IP network side connection port 408 primary port I-1
409 Secondary port I-2
410 Maintenance terminal 501 for various settings Route control unit 502 Route information management unit 503 Packet reception unit 504 Route monitoring unit 505 Packet transmission unit 507 Normal packet 508 that is not a failure monitoring packet 508 Failure monitoring response packet 509 Failure monitoring packet 1101 Region A
1102 Region B
1105 Edge router 1-1
1106 Edge router 1-2
1107 edge router 2-1
1108 Edge router 2-2
1110 Path switching device A-1
1111 Path switching device A-2
1112 Path switching device A-3
1113 Path switching device B-1
1114 Path switching device B-2
1115 Path switching device B-3
1121 Node A-1
1122 Node A-2
1123 Node A-x
1124 Node B-1
1125 Node B-2
1126 Node B-x
1130 LSP communication path 1
1131 LSP communication path 2
1141 Fault monitoring packet 1142 Fault monitoring response packet 1143 Fault monitoring packet 1144 Fault monitoring response packet

Claims (11)

A communication path switching device used in a communication network in which a communication path is configured by communication connection of a plurality of routing devices,
A path control unit that selects a communication path to be used from a plurality of communication paths that are determined not to pass through the physically same routing device;
A transmission unit that transmits a signal to another device connected to any of the plurality of communication paths;
A receiving unit for receiving a response signal from the other device with respect to the signal;
A monitoring unit that monitors the presence or absence of a failure in the communication path based on whether or not the response signal is received;
A management unit that selects a communication path to be used from the plurality of communication paths based on the result of monitoring the presence or absence of a communication path failure in the monitoring unit;
A communication path switching device comprising: 2. The communication path switching apparatus according to claim 1, wherein the signal is constituted by a packet. 2. The communication path switching apparatus according to claim 1, wherein the response signal is constituted by a packet. The communication path switching apparatus according to any one of claims 1 to 3, wherein the signal is periodically transmitted. 5. The communication path switching apparatus according to claim 4, wherein the cycle is variable. 7. The communication path switching device according to claim 1, wherein the communication path exists on an Internet Protocol network. 8. The communication path switching device according to claim 7, wherein the communication path is a Label Switched Path. 8. The communication path switching apparatus according to claim 7, wherein the label switched path communication path is realized by a multi-protocol label switching technique. A communication system in which a communication path is configured by communication-connecting a plurality of routing devices,
A plurality of communication paths determined not to go through physically the same routing device;
A first communication path switching device that selects a communication path to be used from the plurality of communication paths;
A second communication path switching device connected to any of the plurality of communication paths;
Have
The first communication path switching device transmits a signal to the second communication path switching device;
Based on the result of the first communication path switching device monitoring whether or not there is a failure in the communication path based on whether or not a response signal is received from the second communication path switching device with respect to the signal, A communication system characterized by selecting a communication path to be used. In a communication network in which a communication path is configured by communication connection of a plurality of routing devices,
A communication path switching method for selecting a communication path to be used from among a plurality of communication paths that are determined not to go through physically the same routing device,
A transmission step of transmitting a signal to another device existing on the communication path;
Receiving a response signal from the other device for the signal;
A monitoring step of monitoring the presence or absence of a failure in the communication path, depending on whether or not the response signal is received;
As a result of monitoring the presence or absence of a failure in the communication path in the monitoring step, if there is a failure in the communication path, stopping the use of the communication path;
A communication path switching method characterized by comprising: In a communication system in which a communication path is configured by communication connection of a plurality of routing devices,
A communication path switching method for selecting a communication path to be used from among a plurality of communication paths that are determined not to go through physically the same routing device,
A first communication path switching device that selects a communication path to be used from among the plurality of communication paths transmits a signal to a second communication path switching device connected to one of the plurality of communication paths. And steps to
The first communication path switching device receiving a response signal from the second communication path switching device to the signal;
As a result of monitoring the presence or absence of a failure in the communication path according to the presence or absence of reception of the response signal, if there is a failure in the communication path, the step of stopping the use of the communication path;
A communication path switching method characterized by comprising:

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