WO2012097595A1

WO2012097595A1 - Method and system for implementing shared-mesh protection

Info

Publication number: WO2012097595A1
Application number: PCT/CN2011/079004
Authority: WO
Inventors: 张媛媛; 富森; 董均; 罗彬�; 安高峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-01-19
Filing date: 2011-08-26
Publication date: 2012-07-26
Also published as: CN102611604A; CN102611604B

Abstract

Disclosed is a method for implementing shared-mesh protection, including: in shared-mesh protection, a fault detection node triggers a switching request, and executes the corresponding protection switching according to the response of a downstream node; and the downstream node decides to continue to transfer according to the specified path or to respond to the request of an upstream node according to the signalling contents of the switching request. Also disclosed is a system for implementing shared-mesh protection, wherein a protection switching unit in the system is configured to trigger a switching request by a fault detection node and execute the corresponding protection switching according to the response of a downstream node; and the downstream node decides to continue to transfer according to the specified path or to respond to the request of an upstream node according to the signalling contents of the switching request. The application of the method and system in the present invention can implement protection switching based on the signalling contents and transfer of shared-mesh protection.

Description

Method and system for implementing shared mesh protection

The present invention relates to a technique for implementing protection switching based on signaling sharing network protection, and in particular, to a method and system for implementing shared network protection in a network with resource preemption and multi-span failure. Background technique

Network topology is becoming more and more complex, and people's requirements for service bandwidth and performance are also increasing. Shared mesh protection has a higher bandwidth utilization, and its protection switching time is also better than the control plane recovery time. It is a preferred network structure. In shared mesh protection, the protection architecture can use 1:N or M:N or (1:1) n protection. The protection switching scenario in the network is very complicated. How to use the signaling mechanism to implement protection switching is very important. So far, the standard for signaling implementation methods for shared mesh protection has not been established, so that there is no scheme for implementing protection switching based on signaling content and transmission based on shared mesh protection. Summary of the invention

In view of this, the main object of the present invention is to provide a shared mesh protection implementation method and system, which can implement protection switching based on signaling content and delivery of shared mesh protection.

In order to solve the above technical problem, the technical solution of the present invention is implemented as follows:

A shared mesh protection implementation method includes: in a shared mesh protection, a fault detection node triggers a switching request, and performs a corresponding protection switching according to a response of the downstream node; the downstream node decides to continue according to the signaling content of the switching request. Specify the path to pass, or reply to the request of the upstream node.

The signaling content includes at least: a type of the request/status, a requested working service identifier, a requested protection path identifier, and a protection type of the protection structure. The signaling delivery manner of the switching request specifically includes: an inband mode or an outband mode;

The inband mode is transmitted along the protection path along with the service, and the outband mode is not restricted by the path. The method further includes: transmitting the switching request to a next node of the specified path according to the protection path identifier of the switching request.

The method further includes: performing priority detection by a node on the protection path; the node on each protection path compares the local state priority with the switching request signaling state priority, and the local state priority is higher than the switching request signaling In the state priority state, the switching request is rejected, and the current local state of the upstream node is indicated;

When the local state priority is lower than the switching request signaling state priority, the switching request is continued to be delivered to the next node of the specified path. If the switching request is not rejected from the first node to the tail node, the tail node performs protection switching. And sending a reverse request, the node receiving the reverse request performs protection switching one by one and continues to send the reverse request until the first node completes the protection switching.

The method further includes: when the resource is preempted by the high-priority work service, the shared spanned node indicates that the work service is returned to the working path, or is switched to another protection path that is preempted by the work service.

A shared mesh protection implementation system, comprising: a protection switching unit in a shared mesh protection, configured to trigger a switching request by a fault detecting node, and perform a corresponding protection switching according to a response of the downstream node; the downstream node according to the switching request The content of the signaling decides to continue to pass the specified path or to respond to the request of the upstream node.

The signaling content at least includes: a request/state type, a requested work service identifier, a requested protection path identifier, and a protection type protection type.

The signaling delivery manner of the switching request specifically includes: an inband mode or an outband mode;

Wherein, the in-band mode is transmitted along with the protection path, and the out-of-band mode is not limited by the path. The system further includes a detecting unit, configured to perform priority detection by a node on the protection path; the node on each protection path compares the local state priority with the switching request signaling state priority, and the local state priority is higher than When the request signaling state priority is reversed, the switching request is rejected, and the current local state of the upstream node is indicated; when the local state priority is lower than the switching request signaling state priority, the switching request is continued to be delivered to the next node of the specified path. ;

The protection switching unit is further configured to: if the switching request is not rejected from the first node to the tail node, the tail node performs protection switching and sends a reverse request, and the node that receives the reverse request performs protection switching one by one and continues to send the reverse To the request, until the first node completes the protection switch.

In the shared mesh protection of the present invention, the fault detection node triggers the switching request, and performs corresponding protection switching according to the response of the downstream node; the downstream node decides to continue to transmit according to the specified path according to the signaling content of the switching request, or to the upstream node. The request is answered. With the present invention, protection switching can be implemented based on signaling content and delivery of shared mesh protection. DRAWINGS

1 is a schematic diagram of a shared mesh protection structure according to the present invention;

2 is a schematic diagram of a protection span fault according to the present invention;

3 is a schematic diagram of a high priority working service failure according to the present invention;

4 is a schematic diagram of a low priority working service failure according to the present invention;

Figure 5 is a schematic diagram showing the disappearance of the protection span fault according to the present invention;

6 is a schematic diagram of a work of disappearing and returning a high-priority work service according to the present invention;

FIG. 7 is a schematic diagram showing the failure of a high-priority service service in the present invention and the switching of a low-priority service;

Figure 8 is a timing diagram of signaling in the process of PS2 fault generation, W2 fault generation, W1 fault generation, and PS2 fault disappearance processing in the structure of Figure 1.

9 is a timing chart of signaling process in which the W2 fault disappears and the W1 fault disappears in the structure of FIG. 1; FIG. 10 is a schematic diagram of the M:N structure shared mesh protection structure according to the present invention; 11 is a schematic diagram of a fault of a low priority working service in a M:N structure shared mesh protection according to the present invention;

12 is a schematic diagram of a high priority service preemption protection resource and a low priority service switching to another protection path according to the present invention;

13 is a schematic diagram of signaling re-triggering according to the present invention DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is a scheme for implementing protection switching based on signaling content and transmission of shared mesh protection. By sharing signaling content and delivery in mesh protection, shared mesh protection can be implemented in multiple scenarios. .

A method for implementing shared mesh protection, the method mainly includes the following contents:

Plan the services in shared mesh protection, you can use 1:N or M:N or (1:1) n protection structure; determine the priority of the service, record the configuration information on the node; configuration information on each node The working service identifier and the protection path identifier of the node are included, and the cross-section identifier and the span link information of the node included in the protection path are as shown in Table 1. Table 1 is a node configuration information table. The same protection path, there are two span links on the middle node of the path, and there is only one span link on the nodes at both ends. The node of the next hop can be known according to the configuration information located locally at the node.

Table 1

Further, on one node, the protection path state can be obtained by the spanned state included in the protection path, as shown in Table 2, Table 2 is the protection path state information table, and Table 2 also includes the state of the protection path span. Cross-segment status includes: span failure, span lock, span usage, span idle, and more.

Protection path identification Protection path status Cross-segment 1 identification Cross-segment 1 status Cross-segment 2 identification Cross-segment 2 status

2 Further, the signaling content is determined, and the signaling content includes: a type of the request/state, a requested working service identifier, a requested protection path identifier, and a protection type of the protection structure. Determine which business operations are performed according to the content of the signaling. Among them, the type of request/status includes fault, external command, and protection processing status. When the requested work service identifier or the requested protection path identifier is transmitted in n bits, the identifier is defined as: 0 represents an empty signal or an invalid path number; 1 , ..., 2n-l represents a normal service signal or path number . The protection types of the protection structure include: Switching type (single item, bidirectional); Operation type (non-return type, return type). The following takes the signaling of the Optical Transport Network (OTN) as an example. As shown in Table 3, Table 3 is the overhead content table in the OTN. Table 4 is a definition table of the overhead fields in Table 3.

Further, an implementation of signaling delivery is determined. It can be transferred in-band or out-of-band. The in-band mode is delivered with the service, and the out-of-band mode is not limited by the path. The signaling channel uses a protection path that is passed point by point.

Further, the direction of transmission of the signaling is determined. The node on each protection path determines which path to transmit based on the protection path identifier requested in the received signaling. The next hop direction of the signaling is determined based on the cross-section link information. From the request of span 1 , the next hop direction is span 2, the request from span 2, and the next hop is span 1. When the signaling arrives at both ends of the protection path, the signaling forwarding stops because there is only one span link.

Further, to determine the type of protocol, a two-phase mode or a three-phase mode can be used. Here, the two-phase mode is that the first and last nodes in the connection protection domain need to exchange two messages (Z->A, A->Z). The three-phase mode is that the first and last nodes in the connection protection domain need to exchange three messages (Z->A, A->Z, Z->A). The invention triggers a switching request by the fault detecting node, and performs a corresponding switching action according to the response of the downstream node; the downstream node decides to continue to transmit according to the specified path according to the content of the request signaling, or responds to the upstream request.

Further, the determining condition that the signaling can be transmitted to the next hop is determined by the node on the protection path, and the node performs the judgment according to the local state, including the fault state of the span, the resource occupation status of the span, and the spanned External command. When it is judged that the priority of the request state is lower than the local state, the request is rejected and the current local state is indicated.

Further, when the resource is preempted by the high priority service, the shared span node indicates that the preempted service returns to the working path, or, if the condition permits, switches to another protection path.

The invention is illustrated by way of example below.

Example 1: The OTN is used as an example to illustrate the implementation of the signaling-based protection in the shared mesh protection. The signaling transmission mode is the inband overhead mode and the protocol type is the two-phase mode. For the structure shown in FIG. 1, the priority of the work service W1 is lower than the priority of the work service W2. The failure of the protection span PS2 is as shown in Fig. 2, that is, the node D to the node E are faulty. The failure of the protection span PS2 only affects the protection path P1 and does not affect the protection path P2.

When the working service W2 fails, the node H as the first node sends a protection switching request, and requests to switch the working service W2 to the protection path P2, then the request signaling passes through the nodes F and E, and finally reaches the node G, which is the tail node. Determining that the request signaling is a high priority request, first performing bridging and switching, and then transmitting reverse request signaling, and the nodes E and F are bridged after receiving the reverse request signaling, and finally the node H receives the reverse request signaling. Bridge and switch. The signaling transfer process is shown in Figure 3.

When the working service W1 fails, the node A sends a protection switching request to the node D, and the node D determines that the local priority is higher than the request signaling, rejects the request, and indicates the current local state, that is, sends a protection service fault to the node A. The signaling transfer process is shown in Figure 4.

When the protection span PS2 fails, the node D detects the current cost, detects that the request signaling priority is higher than the local priority, and sends the request signaling to the node E. The node E detects that the local high-priority service W2 occupies the protection resource. Rejecting the request and indicating the current local state, that is, responding to the high priority service W2 occupies the protection resource indication to the node D. The signaling transfer process is shown in Figure 5.

The signaling timing of the above process is shown in Figure 8.

When the G->H direction fault disappears, the node H detects that the fault disappears, sends a wait for recovery time (WTR) request to the node F, and the node F sends a WTR request to the node E after receiving the WTR request, and the node E is at the next node. When G sends the WTR request, the W1 working fault signaling from the D direction is also sent to the node F, and the node F sends the request signaling to the node C, and the signaling transmission process is as shown in FIG. 6.

After receiving the request signaling from the node F, the node C performs bridging switching and replies to the node F with the reverse request signaling. After receiving the reverse request signaling, the node F performs bridging and sends to the node E. Reverse request signaling, and send low priority traffic W1 to the node H to occupy protection resources. Node H returns to work after receiving the request. After receiving the reverse request signaling, the node E performs bridging, sends reverse request signaling to the node D, and sends the low priority service W1 to the node G to occupy the protection resource. After receiving the request, the node G returns to work. After receiving the reverse request signaling, the node D performs bridging and sends reverse request signaling to the node A. After receiving the reverse request signaling, the node A performs the bridge switching and switches the working service W1 to the protection path P1. The signaling transfer process is shown in Figure 7.

The signaling timing of the above process is shown in Figure 9.

Example 2: Take the M:N structure shared mesh protection as an example to describe the signaling-based protection implementation.

For the structure shown in Figure 10, the priority of the work service W1 is higher than the priority of the work service W2. The work service W2 fails as shown in Figure 11.

The working service W1 also fails. When the protection resource is preempted by the working service W1, as shown in FIG. 12, the node C and the node D respectively notify the node E and the node F, and the protection service is occupied by the high priority service W1. Node F will re-trigger the alarm process and switch to protection path P3.

Example 3: Take the out-of-band mode as an example to describe a signaling-based protection implementation.

The signaling in the outband mode is different from the signaling in the overhead mode. The signaling in the outband mode is not restricted by the channel fault, and the signaling channel does not always send signaling. Therefore, the signaling processing and the overhead mode are slightly different. different. The overhead mode is that the inter-segment is broken, the service is interrupted, and the overhead mode cannot be used for signaling. However, the out-of-band method is not restricted by the channel failure, so the signaling is intended to be transmitted to wherever. The current request status and remote request status need to be recorded on the node at the same time. When the condition that causes the decision failure on the protection path node disappears, it is necessary to send a judgment failure disappear indication to re-trigger the request of the upstream node. After the protection span fault disappears in Figure 5, node D records that there is a switch request at the remote end of PS1, and sends no request to node A, and re-energizes node A to send a switch request, as shown in Figure 13.

The following is the corresponding node configuration information in FIG. 1 and the corresponding node states in FIG. 2 to FIG. 7 Information is provided for explanation.

In Figure 1, the configuration information of node D is shown in Table 5. The configuration information of node E is shown in Table 6. The configuration information of node F is shown in Table 7.

In Figure 2, the status information of node D is shown in Table 8, the status information of node E is shown in Table 9, and the status information of node F is shown in Table 10.

P1 failure PS1 idle PS2 failure

Table 8

P1 idle PS2 idle PS3 idle

P2 idle PS3 idle PS5 idle

Table 9

P1 idle PS3 idle PS4 idle

P2 idle PS3 idle PS6 idle

Table 10

In Figure 3, the status information of node D is shown in Table 11, the status information of node E is shown in Table 12, and the status information of node F is shown in Table 13.

Protection path identification Protection path status Protection path span 1 Span 1 State Protection path span 2 Span 2 State

P1 failure PS1 idle PS2 failure Protection path identification protection path status protection path span 1 span 1 state protection path span 2 span 2 state

PI high priority service PS2 idle PS3 used by P2 occupation of protection resources

P2 Busy PS3 is used by P2 PS5 is used by P2 Table 12

PI high priority service PS3 is used by P2 PS4 idle

Occupy protection resources

P2 Busy PS3 is used by P2 using PS6

In Figure 4, the status information of node D is shown in Table 14, the status information of node E is shown in Table 15, and the status information of node F is shown in Table 16.

P1 failure PS1 idle PS2 failure

Table 14

P1 high priority service PS2 idle PS3 used by P2 occupation of protection resources

P2 Busy PS3 is used by P2 PS5 is used by P2 Table 15

P1 high priority service PS3 is used by P2 PS4 idle

Occupy protection resources

P2 Busy PS3 is used by P2 PS6 is used by P2 Table 16

In Figure 5, the status information of node D is shown in Table 17, the status information of node E is shown in Table 18, and the status information of node F is shown in Table 19.

Table 19

In Figure 6, the status information of node D is shown in Table 20. The status information of node E is shown in Table 21. The status information of node F is shown in Table 22.

P1 idle PS1 idle PS2 idle

Table 20

P2 Busy PS3 is used by P2 PS5 is used by P2 Table 21

P1 high priority service PS3 is used by P2 PS4 idle

Occupy protection resources

P2 Busy PS3 is used by P2 PS6 is used by P2 Table 22

In Figure 7, the status information of node D is shown in Table 23, the status information of node E is shown in Table 24, and the status information of node F is shown in Table 25.

P1 Busy PS1 is used by P1 PS2 is used by P1 Table 23

P1 is busy PS2 is used by P1 PS3 is used by P1

P2 low priority service PS3 is used by P1 PS5 idle

Occupy protection resources

Table 24

P1 is busy PS3 is used by P1 PS4 is used by P1

P2 low priority service PS3 is used by P1 PS6 idle

Occupy protection resources

Table 25

A shared mesh protection implementation system, the system comprising: a protection switching unit in a shared mesh protection, wherein the protection switching unit is configured to trigger a switching request by the fault detecting node, and perform a corresponding protection switching according to the response of the downstream node; The node decides to continue to transmit according to the specified path according to the signaling content of the switching request, or responds to the request of the upstream node. Here, the signaling content at least includes: a type of the request/state, a requested work service identifier, a requested protection path identifier, and a protection type of the protection structure. It should be noted here that the signaling includes signaling related to switching, such as a reverse request, a reverse response request, and the like.

Here, the signaling delivery mode of the switching request specifically includes: an in-band overhead mode or an out-of-band mode; wherein the in-band overhead mode is transmitted point by point when being transmitted, and is restricted by the channel failure, and is transmitted along with the protection path; The out-of-band method is not limited by channel failure, and does not need to be transmitted point by point, and is not limited by the path.

Here, the system further includes a detecting unit configured to perform priority detection by a node on the protection path; the node on each protection path compares the local state priority with the switching request signaling state priority, and the local state priority When the switching request signaling state priority is higher than the switching request state priority, the switching request is rejected, and the current local state of the upstream node is indicated; when the local state priority is lower than the switching request signaling state priority, the delivery to the next node of the specified path is continued. Switch the request. The protection switching unit further performs protection switching and sends a reverse request if the switching request is not rejected from the first node to the tail node, and the node receiving the reverse request performs protection switching one by one and continues to send the reverse request until the first The node completes the protection switching.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A shared mesh protection implementation method, comprising: in a shared mesh protection, a fault detection node triggers a switching request, and performs a corresponding protection switching according to a response of a downstream node; the downstream node according to the switching request The content of the signaling decides to continue to pass the specified path or to respond to the request of the upstream node.

The method according to claim 1, wherein the signaling content comprises at least: a type of request/state, a requested work service identifier, a requested protection path identifier, and a protection type of the protection structure.

The method according to claim 1, wherein the signaling delivery manner of the switching request specifically includes: an in-band mode or an out-of-band mode;

The inband mode is transmitted along the protection path along with the service, and the outband mode is not restricted by the path.

The method according to claim 2, wherein the method further comprises: transmitting the switching request to a next node of the specified path according to the protection path identifier of the switching request.

The method according to claim 1, wherein the method further comprises: performing priority detection by a node on the protection path;

The node on each protection path compares the local state priority with the switching request signaling state priority. When the local state priority is higher than the switching request signaling state priority, the switching request is rejected, and the current local state of the upstream node is indicated;

The method according to any one of claims 1 to 5, further comprising: when the resource is preempted by the high priority work service, the shared span node indicates that the work service is returned to the work path, or Switch to another protection path that is preempted by the work business.

A shared mesh protection implementation system, comprising: a protection switching unit in a shared mesh protection, configured to trigger a switching request by a fault detecting node, and perform a corresponding protection switching according to a response of the downstream node; The downstream node decides to continue to transmit according to the specified path according to the signaling content of the switching request, or responds to the request of the upstream node.

The system according to claim 7, wherein the signaling content comprises at least: a type of request/state, a requested work service identifier, a requested protection path identifier, and a protection type of the protection structure.

The system according to claim 7, wherein the signaling delivery manner of the switching request specifically includes: an in-band mode or an out-of-band mode;

Wherein, the in-band mode is transmitted along with the protection path, and the out-of-band mode is not limited by the path.

10. The system according to any one of claims 7 to 9, characterized in that the system further comprises a detecting unit for performing priority detection by nodes on the protection path; the nodes on each protection path are compared with the local state first. Level and priority of the switching request signaling state. When the local state priority is higher than the switching request signaling state priority, the switching request is rejected, and the current local state of the upstream node is indicated; when the local state priority is lower than the switching request signaling state At the priority level, the transfer request is continued to be delivered to the next node of the specified path;