CN1194507C

CN1194507C - Bidirectional channel restitution in automatic optical exchange network

Info

Publication number: CN1194507C
Application number: CNB031148107A
Authority: CN
Inventors: 王晓冬; 金耀辉; 张春蕾; 胡卫生; 姜淳
Original assignee: Shanghai Jiaotong University
Current assignee: Shanghai Jiaotong University
Priority date: 2003-01-09
Filing date: 2003-01-09
Publication date: 2005-03-23
Anticipated expiration: 2023-01-09
Also published as: CN1424827A

Abstract

The present invention relates to a bidirectional channel restitution in an automatic optical switching network, which is used for finding, informing and debugging link failures in an automatic switching transfer network (ASTN) and an automatic optical switching network (AOSN). The present invention is characterized in that after a link failure is found, an entrance node of a channel begins to calculate a new channel different from an original channel for carrying original interrupt service; an intermediate node does not make any movement, and an exit node informs the entrance node of the failure situation; after new channel calculation is finished, the entrance node begins to build the signaling process of a channel; after the process of building the channel, the original channel is dismantled. The method of the present invention considers the parallel operation among different nodes, fully utilizes the parallel operation inside the nodes of an automatic switching network, and accelerates the restitution process. The present invention is suitable for the restitution of failures in a bidirectional channel.

Description

Duplex channel restoration methods in the automatic optical exchange network

Technical field:

The present invention relates to the duplex channel restoration methods in a kind of automatic optical exchange network, be applicable to the recovery of link failure in the automatic optical switching network, belong to technical field of optical fiber communication.

Technical background:

In automatic switched transport network or ASON, when link occurs fault, at first show as the light signal that node receives and lose (or other fault message).For duplex channel, the fault of link may occur in the forward path, also may occur in the backward channel, also may occur in forward path and backward channel simultaneously.Break down for forward path, the Egress node discovery light signal of passage is lost; For backward channel, the Ingress node of passage can find that light signal loses; And for two-way fault, Egress node and Ingress node all can be found losing of light signal.After Ingress node and Egress node are found losing of light signal, must finish and remove cross-coupled work, because new tunnel and former passage some port in Ingress node and Egress node is shared.

Recovery process relates to the road construction process, that is: build one and can avoid the fault point, can bear the passage of former business again.For the mode based on routing restoration, newly-built passage and former passage can not shared any link, and this reset mode has been avoided the increase of the recovery time that accurate location brings.Advantage based on the recovery of passage is to have dynamic characteristic, does not need to be in advance the outer resource of the recovery retention of passage.

But the present restoration methods based on passage is serial operation, that is: fault notification, route are calculated, remove interconnection, road construction process, torn open and pass by journey.Do not consider the concurrency between these operations, so resume speed is slower.And the recovery situation of bi-directional path many than the recovery situation complexity of one-way passage, there be not publishing of bi-directional path recovery scheme at present.Therefore the recovery difficult point based on passage is: how (1) improves resume speed; (2) how to simplify the operation.

Summary of the invention:

The objective of the invention is at the deficiencies in the prior art, propose the duplex channel restoration methods in a kind of resume speed automatic optical exchange network very fast and simple to operate.

For realizing this purpose, the present invention proposes a kind of reset mode of bi-directional path.Its principal character is: after finding link failure (light signal is lost), the Ingress node of passage begins route and calculates, and finds out new passage, is used for carrying former interrupting service.Intermediate node is not done any action, and Egress node is then failure condition notice Ingress node.After new tunnel was calculated and to be finished, Ingress node began the signaling procedure of road construction, just began to remove former passage after finishing the road construction process.

Because in recovery process, Ingress node has been served as crucial role, add the randomness that incident takes place in the distributed network control, so the operation of Ingress node is quite complicated.In order to add the process of quick-recovery, the present invention is with parallel the carrying out of some operation (such as the interconnection of calculating route and releasing fault paths).The two does not have dependence successively, and is finished by different functional parts.

And, after it finds that light signal is lost, when sending out fault notification, can remove cross-coupled action at Egress node.Concerning intermediate node, it has only the standard road construction in the automatic switching network and tears open and pass by journey, need not to recovering to do special processing.Therefore after intermediate node finds that light signal is lost, need not action.

The concrete operations rule of each node is as follows in the passage of the present invention:

(1) after the intermediate node of optical channel finds that light signal is lost, there is not any action.

(2) after Egress node finds that light signal is lost, carry out parallel work-flow, promptly when a fault notification signaling is given the inlet node, remove interconnection.

(3) Ingress node finds that light signal loses, perhaps receive the fault notification of Egress node after, carry out parallel work-flow: interconnection is calculated and removed to route.

(4) after calculating of Ingress node route and releasing interconnection are all finished, the signaling procedure that the beginning new tunnel is set up.

(5) the Ingress node new tunnel is set up, and after receiving fault notification, begins the signaling procedure that former passage is removed.

Method of the present invention has been considered the parallel work-flow between the different nodes, and makes full use of the parallel work-flow of automatic switching network intra-node, has accelerated recovery process, is applicable to the recovery of duplex channel fault.Therefore have the following advantages: 1) be fit to all kinds of fault recoveries of two-way link, avoided doing independent processing for the situation of every class fault.2) Ingress node and Egress node adopt parallel work-flow, have shortened the time of recovering.3) intermediate node only relates to common road construction and tears open and pass by journey, and is simple to operate.

Method of the present invention has been considered the parallel work-flow between the different nodes, and make full use of the parallel work-flow of automatic switching network intra-node, accelerated recovery process, be applicable to the recovery of duplex channel fault, can be applicable to discovery, announcement and the recovery of link failure in automatic switched transport network (ASTN) and the ASON (ASON).

Description of drawings

Fig. 1 is in the recovery process, and the port of Ingress node and Egress node is connected the variation schematic diagram.

Fig. 2 analyzes the schematic network structure that adopts in the embodiment of the invention.

Have in the network configuration of Fig. 2 bi-directional path (I, T1, E).

Fig. 3 is the signaling of the embodiment of the invention 1, incident and action timing diagram.

Fig. 4 is the signaling of the embodiment of the invention 2, incident and action timing diagram.

Fig. 5 is the signaling of the embodiment of the invention 3, incident and action timing diagram.

Among Fig. 3 Fig. 4 Fig. 5: find that 1. light signal loses; 2. remove interconnection; 3. removing interconnection finishes; 4. calculate route; 5. route is calculated and is finished.

Embodiment:

Below in conjunction with accompanying drawing and three embodiment technical scheme of the present invention is further described.

Embodiment 1:

In network environment shown in Figure 2, existing bi-directional light passage: (I, T1, E).Suppose that now I breaks down to the link of T1 direction, promptly the B point breaks down.T1 and E detect light signal and lose.The action of each node is as follows:

T1 does not move because be intermediate node.

E is an Egress node, thus fault notification I, and remove interconnection.

Ingress node I at first receives fault notification, and operation afterwards is followed successively by:

1) route is calculated, and removes interconnection simultaneously.

2) suppose that the new tunnel of calculating is that (I, T2 E), after the releasing interconnection is finished, begin the signaling procedure (send the road construction request and give T2) of road construction.

3) (receiving the road construction response) finished in road construction, begins to tear open the signaling procedure (send and tear the road request open to T1) on road.

4) tear the road open and finish (receive and tear the road response open), recovery process finishes.

Whole process such as Fig. 3 of recovering.Concrete signaling realizes with reference to constraint tag distribution protocol CR-LDP and the RSVP RSVP of IETF.

Embodiment 2:

In network environment shown in Figure 2, existing bi-directional light passage: (I, T1, E).Suppose that now T1 breaks down to the link of I direction, promptly the A point breaks down.I detects light signal and loses.The action of each node is as follows:

Ingress node I finds that at first light signal loses, and operation afterwards is followed successively by:

1) route is calculated, and removes interconnection simultaneously.

3) (receiving the road construction response) finished in road construction, and after receiving the fault notification of E, begins to tear open the signaling procedure (send and tear the road request open to T1) on road.

After I removed interconnection, T1 and E discovery light signal were lost, and this moment, E sent fault notification to I, and the T1 attonity.

Whole process such as Fig. 4.

Embodiment 3:

In network environment shown in Figure 2, existing bi-directional light passage: (I, T1, E).Suppose that now the link between T1 and the I all breaks down, promptly 2 of A, B break down.The action of each node is identical with embodiment 2, and just among the embodiment 2: T1 and E find that the reason that light signal is lost is because I has removed interconnection.And among the embodiment 3: T1 and E find that the reason that light signal is lost is a link failure.Whole process such as Fig. 5.

Claims

1, the duplex channel restoration methods in a kind of automatic optical exchange network is characterized in that may further comprise the steps:

1) after the intermediate node of optical channel finds that light signal is lost, there is not any action;

2) after Egress node finds that light signal is lost, carry out parallel work-flow: send out the fault notification signaling and give the inlet node and remove interconnection;

3) Ingress node finds that light signal loses, perhaps receive the fault notification of Egress node after, carry out parallel work-flow: interconnection is calculated and removed to route;

4) after calculating of Ingress node route and releasing interconnection are all finished, the signaling procedure that the beginning new tunnel is set up;

5) the Ingress node new tunnel is set up, and after receiving fault notification, begins the signaling procedure that former passage is removed.