JP2003060680A - System and method for processing network trouble, node, program and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten a service interruption time of a faulty link upon occurrence of a link trouble in an MPLS network. SOLUTION: At the time of setting LSP, address of an MPLS network edge node or a segment end node is held in an LSP data base section 5a at each node 1-4. Upon occurrence of a link trouble, address of an MPLS network edge node or a segment end node 4 detected from information held in the LSP data base section 5a is set in the destination address of APS message for each LSP at a node 1 where a trouble is detected through a trouble detecting section 6a. At repeating nodes 2 and 3, soft or hard transfer is performed by the destination address of a label withdraw message and an LSP contained in the faulty link is informed directly to the MPLS network edge node or the segment end node 4.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an IETF (Intern
et Engineering Task Force (RFC) (Request For Co
mment) 3031 and RFC3036 standard MPLS (Mul)
ti protocol label switching) relates to a technique for dealing with a link failure in a network, and in particular, a network failure processing system and method, a node, and a program suitable for fast failure notification to an MPLS network edge node or a segment end node, and It relates to a storage medium.

[0002]

2. Description of the Related Art IETF RFC 3031 and RFC 30
One of the techniques for ensuring reliability in the 36 standard MPLS network is path switching at the time of a link node failure. Hereinafter, a conventional technique for dealing with a link failure in the MPLS network will be described with reference to FIG. .

FIG. 9 is an explanatory diagram showing an example of the processing operation in each node at the time of a link failure in the conventional MPLS network.

In the conventional technique, the SDH is used in the node 91.
(Synchronous Digital Hierarchy) When a fault is detected, the node 91 that has detected the fault notifies the management software after a certain protection time, and this management software notifies the LSP (Label Switched Pat) accommodated in the fault link.
h) FEC (Forwarding Equivalence Class) or LSP-ID (Identification) is searched, and the FEC information or LSP-ID is searched for in IP (Internet Pro).
tocol) packet which is a Label Withdraw Message and is notified to the upstream adjacent node 92.

At this time, this label withdraw message is transmitted by the number of LSPs accommodated in the failed link.

The adjacent node 92 which has received the label withdraw message uses the FEC or LSP-ID for the LS.
P is searched and the label withdraw message is transferred to the upstream adjacent node 93 in the same manner as the node 91.

In this way, the FE of the LSP in which the failure has occurred
The C information or the LSP-ID is added to the label withdraw message and is notified to the node 94 as an MPLS network edge node or a segment end node through the soft processing in each node 92, 93.

At the node 94 as an MPLS network edge node or a segment end node, a transfer table (forwarding table: F table) is identified so as to identify the switching path from the FEC information or LSP-ID and switch to a preset bypass path. Recreate or update to change
Traffic is switched to the detour path by resetting to each line card.

Each of the nodes 91 to 94 has L between adjacent nodes.
The LS that manages the SP and is accommodated in the failed link
To trace the LSP management chain that identifies P,
FEC or L at Hop By Hop
SP-ID search is required. The label withdraw message is LDP (Label) between each node in LSP units.
Distribution Protocol) Transferred over the session.

By transmitting a message for each LSP accommodated in the faulty link, the relay nodes 92 and 93 and the node 94 as an MPLS network edge node or a segment end node can receive FEC or LSP.
-Search by ID to identify the upstream neighbor node address.
Therefore, the search time depends on the number of LSPs accommodated in the failed link. Further, the FEC search at the relay node depends on the number of relay nodes.

As a result of the origin, when the number of messages and the number of relay nodes (92, 93) are large, the failure notification to the MPLS network edge node or the segment end node (94) is delayed and the service interruption time becomes long.

[0012]

The problem to be solved by the prior art is that in the prior art, each relay node that receives a message from a node that has detected a link failure in an MPLS network determines the upstream adjacent node address. Therefore, since the search is performed by FEC or LSP-ID, the time required for the search becomes long.

An object of the present invention is to solve these problems of the prior art and to speed up failure notification to an MPLS network edge node or segment end node when a link failure occurs in the MPLS network. A network fault processing system and method, a node, a program, and a storage medium.

[0014]

In order to achieve the above object, in the network fault processing system and method and node of the present invention, when a link fault occurs in the MPLS network, FEC or LSP-at each relay node is used.
The search by ID is omitted, and the relay node simply transfers the message by soft or hard by the destination address, and quickly notifies the failure of the link to the MPLS network edge node or the segment end node. For example, at the time of setting the LSP, each node holds the address of the MPLS network edge node or the segment end node, and when a link failure occurs, the node that detects the failure instructs the alternate path switching for each LSP. AP
The address of the MPLS network edge node or the segment end node is set as the destination address of the S message, and the relay node performs soft or hard transfer according to the destination address of the APS message, and the LSP accommodated in the failed link is transferred to the MPLS network edge. Notify the node or node at the end of the segment directly.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of a node which is a constituent element of a network fault processing system according to the present invention, and FIG. 2 is an explanation showing a processing operation example of a network fault processing system according to the present invention. Figures and 3
5 is an explanatory diagram showing a configuration example of a message packet generated and transmitted by the node in FIG. 1, FIG. 4 is a block diagram showing another configuration example of the node which is a component of the network failure processing system according to the present invention, FIG. 1 is a block diagram showing an example of a network configuration by the network fault processing system of the present invention, FIG. 6 is an explanatory diagram showing a comparative example of the network fault processing system and method according to the present invention with the prior art, and FIG. 7 is FIG. 5 is a block diagram showing a hardware configuration example of a node in FIG.

In FIG. 7, 71 is a CRT (Cathode Ra
y Tube) or LCD (Liquid Crystal Display) or the like, 72 is an input device such as a keyboard or mouse, 73 is an external storage device such as HDD (Hard Disk Drive), and 74 is a CPU (Central Processing Unit)
74a, main memory 74b, and input / output interface 7
An information processing device including computer 4c or the like for performing computer processing, and 75 is a CD-ROM (Compact Disc-Read Only Memory) or a DVD (Digital Video Disc / Digital Versatile) in which the programs and data according to the present invention are recorded.
Disc), etc., 76 is an optical disc 75
A drive device for reading out the programs and data recorded in the above, and a communication device 77 including a LAN (Local Area Network) card, a modem and the like.

After the programs and data stored on the optical disk 75 are installed in the external storage device 73 by the information processing device 74 via the drive device 76, the CPU 74a reads the external storage device 73 into the main memory 74b.
1 is configured in the information processing device 74 by processing in the information processing device 74, and the nodes 1 to 4 shown in FIG.
In the MPLS network including as a component, the link failure notification to the MPLS network edge node or the segment end node can be efficiently performed as shown in FIG.

That is, in this example, CR is used for signaling.
-LDP (Constraint-based Routing Label Distribu
option protocol, LSP (Label Switche
d Path) setting, at each node 1-4, LSP-ID
To MPLS network edge node address and FEC (Forwarding EquivalenceCl
ass) Holds a list in which information is associated with the LSP.

When a static LSP is set, each node 1 to 4 is set to MPLS when the LSP is set.
A list in which the address of the network edge node or the segment end node and the FEC information are associated with the LSP is held.

Then, the node 1 which has detected the SDH failure
Is the L accommodated in the failed link after the SDH failure is detected.
Search the FEC or LSP-ID of SP from the list,
Fault notification IP packet addressed to the address of the MPLS network edge node or segment end node for each LSP (hereinafter referred to as “APS message” (Automatic Protecti
on Switch message)) is created.

FIG. 3 shows the format of this APS message, which is the same as the Label with Draw message except for the message type ("APS"), but the message is UDP
(Port number 646) (User Datagram Protocol) is used for notification.

The node 1 shown in FIGS. 1 and 2 is connected to this APS.
The FEC information is added to the message, and the message is sent to the node 4 as the MPLS network edge node or the segment end node. Since the LDP session is not possible from the node 1 except the adjacent node 2, the APS message is transferred by UDP.

The relay nodes 2 and 3 forward the APS message (IP packet) addressed to the node 4 as the MPLS network edge node or the segment end node. Therefore, the FEC search process is unnecessary in the relay nodes 2 and 3.

In the node 4 as the MPLS network edge node or the segment end node, the FEC information or the LS is based on the transmitted APS message.
The transfer table is identified by identifying the switching path from the P-ID and switching to the preset detour path (forwarding table:
Recreate (Table F) and reconfigure to each line card. This causes the traffic to switch to the detour path.

In this example, UDP is used, and a plurality of APS messages are sent from the node 1 in order to prevent message leakage.

The details of each of the nodes 1 to 4 will be described below with reference to FIG. 1. Here, the nodes 1 to 4 serve as fault detection nodes for notifying link faults to the MPLS network edge node or the segment end node (node 4). Describe the function.

Each of the nodes 1 to 4 in FIG.
A fault processing unit 5 including an LSP database unit 5a and an APS message packet creation unit 5b, and line processing units 6 and 7
The line processing unit 6 is provided with a fault detecting unit 6a.

In this example, when CR-LDP is used for signaling, each node 1 to 4 has L
The LSP database unit 5a in the failure processing unit 5 holds a list in which the MPLS network edge node address of the MPLS network and the FEC information are associated with the LSP from the SP-ID.

When a static LSP is set, at the time of setting the LSP, each node 1 to 4 makes a list in which the address of the MPLS network edge node or the segment end node and the FEC information are associated with the LSP.
It is held in the LSP database unit 5a in the failure processing unit 5.

When the SDH failure is detected by the failure detecting section 6a, the line processing section 6 notifies the failure processing section 5 of the failure information.

Upon receiving the notification of the occurrence of a failure, the failure processing unit 5 searches the LSP database unit 5a for the LSP accommodated in the failed link, and the address of the MPLS network edge node or the segment end node and the FEC and LSP. -The ID is read out, the APS message packet creation unit 5b creates a message (APS message) for the detour path switching instruction addressed to the address of the MPLS network edge node or the segment end node for each LSP, and the line processing unit 7 is used. And sends it to the MPLS network edge node or the segment end node.

When operating as a relay node, each node 1
In Nos. 4 to 4, since the APS message (IP packet) addressed to the MPLS network edge node or the segment end node is forwarded and transferred, the conventional FEC search process is unnecessary.

When operating as an MPLS network edge node or a segment end node, each node 1 to 4
Then, when the APS message is received, the switching path is identified from the FEC information or the LSP-ID, the transfer table (forwarding table: F table) is recreated so as to switch to the preset detour path, and each line card is written. Reset.
This causes the traffic to switch to the detour path.

In this example, in order to prevent message leakage due to UDP transfer, a plurality of APS messages are sent from the nodes 1 to 4.

In the example shown in FIG. 1 described above, each function relating to the present invention in the nodes 1 to 4 is configured by software, but as in the example shown in FIG. 4, the hardware in the line processing unit is used. Alternatively, each function according to the present invention may be configured.

In the nodes 1a to 4a of the configuration example shown in FIG. 4, the line processing unit 46 and the failure detection unit 46a together with the LS.
The P database unit 45a and the APS message packet creation unit 45b are provided in a hardware configuration, and the MPLS network edge node or the segment end node
Functions as a failure detection node that notifies link failures.

Also in this example, CR-L is used for signaling.
DP (Constraint-based Routing Label Distribution)
Protocol), each node 1
a to 4a, the LSP-ID to the MPLS network edge node address of the MPLS network and the FEC
A list in which the information is associated with the LSP is stored in the L
It is held in the SP database unit 45a.

When a static LSP is set, the MPL is set in each node 1a to 4a when the LSP is set.
The LSP database unit 45a of the line processing unit 46 holds a list in which the S network edge node or segment end node address and the FEC information are associated with the LSP.

In the line processing unit 46, when the SDH fault is detected in the fault detecting unit 46a, the fault is recognized, the LSP stored in the fault link is searched from the LSP database unit 45a, and the MPLS network edge is detected. Address of node or segment end node and FEC
And read the LSP-ID.

Further, in the APS message packet creation unit 45b, a message addressed to the address of the MPLS network edge node or the segment end node is created for each LSP, and the message is returned in the line processing unit 46 or is sent to the switch to be sent to the MPLS network edge. Send to the node or segment end node.

When functioning as a relay node, MPL
Since the APS message (IP packet) addressed to the S network edge node or the segment end node is forwarded and transferred, the FEC search process is unnecessary.

When operating as an MPLS network edge node or a segment end node, the switching table is identified from the FEC information or LSP-ID that has been sent, and a forwarding table (forwarding table) is used so as to switch to a preset bypass path. : F table) and re-create each line card. This causes the traffic to switch to the detour path.

In order to prevent message leakage due to UDP transfer, a plurality of APS messages are sent from the nodes 1a to 4a.

Regarding the network fault processing system and method of the present example using such a node and the conventional fault processing technique, one node or two stages of relay nodes 52 are provided from a node 51 which has detected a fault as shown in FIG. MPLS network edge node or segment end node 53
FIG. 7 shows the result of evaluation in the network for notifying to.

In FIG. 7, the horizontal axis represents the number of LSPs accommodated in the failed link, and the vertical axis represents the time of service interruption.
The respective calculation results are shown. The value was standardized in the prior art with one relay node stage and a service interruption time of 500 LSPs accommodated in the failed link.

It can be seen that when the fault notification technique of this example is used, the service interruption time can be shortened as compared with the conventional technique regardless of whether the relay is one-stage or two-stage. That is, according to the failure notification technique of this example, the search at the relay node can be omitted, and the service interruption time can be shortened by performing the transfer processing by DA (Destination Address).

Next, an example of the processing operation of the node having the configuration shown in FIGS. 1 and 4 will be described with reference to the flowchart of FIG.

FIG. 8 is a flow chart showing an example of the processing procedure of the network failure processing method according to the present invention.

Nodes 1-4 and 1 in FIGS. 1 and 4
a to 4a detect the occurrence of a link failure (step 80).
1) or waiting for the reception of a message (IP packet) (step 802) and detecting a link failure,
The address of the MPLS network edge node or segment end node associated with the LSP, which is stored / stored in the LSP database units 5a and 45a in advance, is read out, and an APS message for detour path switching instruction is created (step 803), and is written in the UDP. And sends it to the MPLS network (step 804).

When a message is received in the processing of step 802, it is judged whether or not it is an APS message addressed to its own node (step 805), and if it is not an APS message addressed to its own node, it is transferred softly or hard. (Step 806), APS addressed to own node
If it is a message, based on the APS message, switching to a preset detour path or searching for a detour path and switching to the detour path is performed (step 80).
7).

As described above, if the APS message is not addressed to the own node, only the soft transfer or the hard transfer is performed, and the failure notification to the MPLS network edge node or the segment end node can be speeded up.

As described above with reference to FIGS. 1 to 8, in the network failure processing system and method of this example,
At the time of LSP setting, at each node 1-4 and 1a-4a, M
The address of the PLS network edge node or the segment end node is held in the LSP database units 5a and 45a, and when a link failure occurs, the nodes 1 and 1a that have detected the failure will send a label withdraw message for each LSP. To the destination address of LSP database section 5
a, 45a sets the address of the MPLS network edge node or segment end node 4, 4a held by the a, 45a, and the relay nodes 2, 2a, 3, 3a set the AP
Soft or hard transfer is performed according to the destination address of the S message, and the LSP accommodated in the failed link is transferred to the M
It directly notifies the PLS network edge node or the segment end node 4 or 4a.

Thus, when a link failure occurs in the MPLS network, the search by FEC or LSP-ID at each relay node is omitted, and the relay node only transfers the message by software or hard by the destination address, The failure notification of the link to the MPLS network edge node or the segment end node can be performed at high speed, the time of service interruption using the failure link can be shortened from the occurrence of the failure, and the reliability of the network is improved.

The present invention is not limited to the examples described with reference to FIGS. 1 to 8 and can be variously modified without departing from the scope of the invention. For example, in this example,
UDP is used to transfer the APS message, but T
It is also possible to use CP (Transmission Control Protocol). As described above, when TCP is used, APS message transfer is performed after the connection between the failure detection node and the MPLS network edge node or the segment end node is established, which requires more time than when UDP is used. However, it is sufficient to transfer one APS message.

Further, in this example, a forwarding table (forwarding table: F table) is used for switching to the detour path at the MPLS network edge node or the segment end node.
Is recreated and changed, but it is also possible to correct and update / change the relevant part.

The Internet, IP packet network, ATM network, etc. can be applied as the MPLS network of this example. Then, for example, when applied to an ATM network, the node configuration shown in FIGS. 1 and 4 is installed in an ATM exchange. In this case, the APS message is transferred not in the IP packet but in the ATM cell.

Further, in the description of the example of FIGS. 1 and 4,
In the node 4 as the MPLS network edge node or the segment end node that has received the APS message, the switching path is identified from the FEC information or the LSP-ID based on the received APS message, and switched to the preset bypass path. By recreating the forwarding table (forwarding table: F table) and resetting it on each line card, the traffic is switched to the detour path. However, as described in FIG. 8, the detour path is searched. Then, switching to the detour path may be performed.

Further, the computer configuration of the node shown in FIG. 7 may be a computer configuration without a keyboard or an optical disk drive device. Also, in this example,
An optical disk is used as a recording medium, but the FD (Flex
ible disk) or the like may be used as the recording medium.
Further, regarding the installation of the program, the program may be downloaded and installed via the network via the communication device.

[0060]

According to the present invention, when a link failure occurs in the MPLS network, it becomes possible to speed up failure notification to the MPLS network edge node or the segment end node, and the failure link is used from the failure occurrence. It is possible to shorten the service interruption time and improve the reliability of the MPLS network.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a node which is a component of a network fault processing system according to the present invention.

FIG. 2 is an explanatory diagram showing an example of processing operation of the network failure processing system according to the present invention.

FIG. 3 is an explanatory diagram showing a configuration example of a message packet generated and transmitted by the node in FIG.

FIG. 4 is a block diagram showing another configuration example of a node which is a component of the network fault processing system according to the present invention.

FIG. 5 is a block diagram showing a network configuration example by the network fault processing system of the present invention.

FIG. 6 is an explanatory diagram showing a comparative example of the network failure processing system and method according to the present invention with the related art.

FIG. 7 is a block diagram showing a hardware configuration example of a node in FIGS. 1 and 4.

FIG. 8 is a flowchart showing a processing procedure example of a network failure processing method according to the present invention.

FIG. 9 is an explanatory diagram showing an example of a processing operation in each node at the time of a link failure in the conventional MPLS network.

[Explanation of symbols]

1-4, 1a-4a, 50-53: node, 5: failure processing unit, 5a: LSP database unit, 5b: APS message packet creation unit, 6, 7: line processing unit, 6a: failure detection unit, 11, 21, 31, 41: LSP search, 1
2, 22, 32, 42: transfer, 45a: LSP database section, 45b: APS message packet creation section, 4
6: line processing unit, 46a: failure detection unit, 71: display device, 72: input device, 73: external storage device, 74: information processing device, 74a: CPU, 74b: main memory, 74
c: input / output interface, 75: optical disk, 76:
Drive device, 77: communication device, 91 to 94: nodes, 91
a to 94a: LSP search, 91b to 94b: transfer.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takashi Kurimoto             2-3-1, Otemachi, Chiyoda-ku, Tokyo             Inside Telegraph and Telephone Corporation F term (reference) 5K030 GA12 HA10 JL10 KA05 LB08                       MB01 MD02

Claims (6)

[Claims] 1. A system for coping with a link failure occurring in an MPLS network, wherein a storage device stores the address of an MPLS network edge node or a segment end node in association with a LSP to be set to a node constituting the MPLS network. Means for storing the link failure, failure detection means for detecting the occurrence of the link failure, and the MPLS corresponding to the LSP accommodated in the failed link.
Creating means for reading the address of the network edge node or the segment end node from the storage device, creating an APS message for detour path switching instruction in which the read address is set as the destination address, and sending the APS message to the MPLS network. A node that provides a sending unit and relays the APS message performs transfer based on the destination address of the APS message,
At the MPLS network edge node or segment end node of the destination address of the APS message, based on the received APS message, switch to a preset detour path, or search for the detour path to reach the detour path. A network fault processing system characterized by switching. 2. A method for coping with a link failure occurring in an MPLS network, wherein a node constituting the MPLS network associates an address of an MPLS network edge node or a segment end node with a storage device in association with a set LSP. And a second procedure for detecting the occurrence of the link failure, and the MPLS corresponding to the LSP accommodated in the failed link.
A third procedure for reading the address of the network edge node or the segment end node from the storage device and creating an APS message for a bypass path switching instruction in which the read address is set as a destination address;
A fourth procedure for sending a message to the MPLS network, and as a node for relaying the APS message,
Transfer based on the destination address of the APS message, and the MPL of the destination address of the APS message
As an S network edge node or a segment end node, based on the received APS message, it switches to a preset bypass path, or searches for a bypass path and switches to the bypass path. Network fault handling method. 3. The network failure processing method according to claim 2, wherein a plurality of the APS messages are UDP-transferred. 4. The computer according to claim 2, or
A program for executing each procedure in the network failure processing method according to claim 3. 5. The computer according to claim 2, or
A computer-readable recording medium in which a program for executing each procedure in the network failure processing method according to claim 3 is recorded. 6. A node constituting an MPLS network,
A means for storing the address of the MPLS network edge node or the segment end node associated with the set LSP in the storage device, a failure detection means for detecting the occurrence of the link failure, and a means for accommodating the failed link Creating means for reading an address of the MPLS network edge node or segment end node corresponding to the LSP from the storage device, and creating an APS message for detour path switching instruction in which the read address is set as a destination address; And a sending means for sending a message to the MPLS network.
When relaying a PS message, transfer is performed based on the destination address of the APS message, and if the destination address of the APS message is its own address, the MP
As an LS network edge node or a segment end node, switching to a preset detour path based on the received APS message, or
A node that searches for a detour path and switches to the detour path.