WO2012037754A1

WO2012037754A1 - Method and node device for realizing bidirectional linear protection switching for multiplex section

Info

Publication number: WO2012037754A1
Application number: PCT/CN2010/079521
Authority: WO
Inventors: 吴青
Original assignee: 中兴通讯股份有限公司
Priority date: 2010-09-26
Filing date: 2010-12-07
Publication date: 2012-03-29
Also published as: CN101951303B; CN101951303A

Abstract

The invention discloses a method for realizing a bidirectional linear protection switching for a multiplex section. The method includes: after a node device calculates the bridging request with the highest priority in a protection group, it performs bridging and switching for the service corresponding to the bridging request, according to a first decision mode. The invention also discloses the node device including at least one working port and one protection port, wherein the working port and the protection port interact with an automatic protection switching (APS) module and the APS module is set for: performing bridging and switching for the service corresponding to a bridging request, according to the first decision mode, after calculating the bridging request with the highest priority in a protection group. The invention can greatly improve the switch efficiency of the bidirectional 1: N linear protection for a multiplex section.

Description

Method and node device for realizing multiplex section bidirectional linear protection switching

The present invention relates to the field of optical network technologies, and in particular, to a method and a node device for implementing bidirectional linear protection switching of a multiplex section.

Background technique

In the Automatic Protection Switched (PSS) protocol specified by the G.841 standard (Synchronous Digital Hierarchy (SDH) network protection structure), the implementation of the multiplex section 1:N bidirectional protection switching is strictly followed. The interaction between the two nodes is three-phase (3-phase) to complete the switching. When the far-end request is the highest request, the bridge of the remote request signal is performed, and the received K2 byte and the signal number in the sent K1 byte indicate the same working service signal, and the switching of the service service is performed. As shown in Figure 1, the process of completing the switch according to 3-phase is as follows:

Initially, both ends of the node device send NR0,0 signaling (NR is no request, both the request bridge signal and the bridged signal are 0). When the left end node device detects that the signal 2 is degraded, it sends SD2,0 (requests the peer bridge signal)

2) ; After the right end node device completes the signal 2 bridging, it sends RR2, 2 (reverse request, the requesting peer also bridges the signal 2, and informs the peer end that the signal 2 bridge is completed); the left end node device completes the bridging of the signal 2 And switching, sending SD2, 2 (notifying the opposite end that the signal 2 is bridged); the right end node device completes the signal 2 switching.

When the right end node device detects that the signal 3 is interrupted, it sends SF3, 2 (requests the peer bridge signal 3, notifying that the peer is still in the state of the bridge signal 2) The left end node device cancels the bridge switching of signal 2, and performs the bridging of signal 3. Then, it transmits RR3, 3 (reverse request, requests the peer bridge signal 3, and informs the opposite end that the signal 3 bridge is completed); the right end node The device completes the bridge of signal 3, sends SF3, 3 (notifies the peer that the signal 3 is bridged). The left end node device completes the signal 3 switching.

When the right end node device detects the failure recovery of the working channel 3, it sends WTR3, 3 (notifies the peer end to enter the switching for the recovery state). The left end node device is still degraded due to the working channel 2, so after the switching of the undo signal 3, the sending is performed.

SD2,3 (request peer bridge signal 2, because SD priority is higher than WTR); right end device undo signal 3 switching and complete signal 2 bridge, send RR2, 2 (reverse request, request peer also bridge signal 2, and inform the opposite end of the completion of the signal 2 bridge); the left end node device completes the bridging and switching of signal 2, sends SD2, 2; the right end node device completes the signal 2 switching.

It can be seen that after detecting the change of the signal, the node device (the local end) first notifies the peer end to bridge the corresponding signal, and then the local end bridges the bridge, and the local end performs the bridge switching, and then the opposite end completes the switching, and the signaling needs to be performed. After the three-way interaction, the bridge switching between the two ends is performed. The decision of the APSs at both ends of the bridge switching process must be performed twice, and the service switching time is longer.

SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is to provide a method and a node device for implementing bidirectional linear protection switching of a multiplex section, so as to improve the multiplexing section 1 without affecting the connection with the device running the standard protocol: N bidirectional linear protection switching efficiency. In order to solve the above problem, the present invention provides a method for implementing bidirectional linear protection switching of a multiplex section. The method includes: after the node device calculates the bridging request with the highest priority in the protection group, performing bridging and switching of the bridging request corresponding service according to the first decision mode. The step of the bridging and switching of the bridging request corresponding service by the node device according to the first decision mode includes: if the node device determines that the node device is configured in the first decision mode, performing bridging of the bridging request corresponding service Switched. The step of the bridging and switching of the bridging request corresponding service by the node device according to the first decision mode includes: if the node device determines that the received multiplex section cost K2 indicates the first decision mode, the bridging request is performed. Correspond to the bridging and switching of services. If the node device determines that the received multiplex section cost K2 indicates the first decision mode, the method further includes: saving the first decision mode; and performing the bridging request according to the first decision mode After the step of bridging and switching the service, the method further includes: transmitting a multiplexing segment overhead K2 indicating the first decision mode. In the process of performing the bridging and switching of the bridging request corresponding service according to the first decision mode, the method further includes: if the node device receives the switching control information sent by the network management, and determines that the switching control information is carried The decision mode is different from the currently executed decision mode, and the decision mode mismatch information is reported to the network management. In order to solve the above problem, the present invention further provides a node device, including at least one working port and one protection port, where the working port and the protection port interact with an automatic protection switching (APS) module, where: the APS module is configured. After the bridging request with the highest priority in the protection group is calculated, bridging and switching of the service corresponding to the bridging request is performed according to the first decision mode. The APS module is configured to perform the bridging request according to the first decision mode as follows Bridging and switching of the corresponding service: If it is determined that the device of the node is configured in the first decision mode, the bridging and switching of the service corresponding to the bridging request is performed. The APS module is configured to perform bridging and switching of the bridging request corresponding service according to the first decision mode as follows: if it is determined that the received multiplex section overhead K2 byte indicates the first decision mode, the bridging is performed. Request bridging and switching of the corresponding service. The APS module is further configured to: save the first decision mode, and further, after completing bridging and switching, send a multiplexing segment overhead K2 indicating the first decision mode. The APS module is further configured to: if receiving the switching control information sent by the network management, and determining that the decision mode carried by the switching control information is different from the currently executed decision mode, reporting the decision mode mismatch information to the network management. The invention provides a method and a node device for realizing the bidirectional linear protection switching of the multiplex section, and reduces the three interactions of the protocol bytes in the switching process to one interaction, and the corresponding decision processing is only one time, which can greatly improve the multiplexing section. 1 : N bidirectional linear protection switching efficiency, thus making up for the deficiencies of other processing units, in particular, the implementation of the multiplex section protection decision is optimized, then the corresponding requirements for other processing units will be reduced accordingly. For example, after the switching efficiency is improved, the requirements for fast detection of alarms can be reduced accordingly. Usually, the alarms are quickly detected by hardware, which can relatively reduce some parameters of the hardware. At the same time, the announcement phase mode also enhances controllability.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a multiplex section 1: N bidirectional linear protection switching 3-phase APS message flow; FIG. 2 is a schematic diagram of a node device according to an embodiment of the present invention; FIG. 4 is a flow chart of a PST bidirectional linear protection switching 1-phase APS message flow according to the present invention; FIG. 5 is a 1-phase node device and a 3-phase node of the present invention; Schematic diagram of the APS message flow of the device's docking. The preferred embodiment of the present invention performs the switching process in Ethernet protection switching (G.8031) and Transport Multi-Protocol Label Switching (T-MPLS) linear protection switching (G.8131). Improvement, introducing only one protocol byte (1-phase) switching execution process between two nodes, effectively improving the switching efficiency of 1:N bidirectional linear protection. In G.8031 and G.8131, bidirectional linear protection switching is performed in a fixed manner. Referring to the above standard provisions, the present invention proposes to implement 1-phase execution in the multiplex section bidirectional 1:N linear protection, mainly to identify the phase in the signaling, and indicate the decision mode of the local end to the opposite end, and negotiate the two ends. Decision-making mode, making protection decisions in a unified mode. At the same time, it also considers the docking of the original processing. The method proposed in this paper also applies to the optical transport network (OTN) linear protection specified in G.873.1. The main idea of the present invention is as follows: The multiplex section 1:N bidirectional linear protection decision uses the 1-phase method. After the node calculates the bridge request with the highest priority in the protection group, it directly completes the bridging of the maximum request corresponding service. Switching, and sending the request to the peer. After receiving the request, if the peer confirms that it is the largest request, it also completes the bridge switching, and the service is restored.

The multiplex section overhead is K2 bytes of b6-b8. The existing standards are defined as follows: 000 00 001-101 Reserved 110 MS-RDI (Reuse Segment Remote Defect Indication)

111 MS-AIS (Reuse Segment Alarm Indication Signal) The present invention will use the reserved bytes therein to negotiate the phase modes (decision mode) indicating both ends, and perform corresponding decisions according to the matching conditions.

The implementation of the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, in the case of no conflict, the embodiments of the present invention and the special embodiments The signs can be combined with each other arbitrarily. At present, the method of the present invention is applied to the multiplex section protection (MSP) of the access side in a packet transport network (PTN) device to improve the protection switching efficiency. A schematic diagram of a node device according to an embodiment of the present invention is shown in FIG. 2. The invention is defined in the multiplex section overhead K2 byte b6-b8, and the definition is as follows:

001 1 -phase 011 3 -phase Established multiplex section 1: 1 The bidirectional protection group includes STM ports #A-1 and #B-1 of line cards A and B, where #A-1 is the working port, # B- 1 is a protection port. The 1:N bidirectional protection group includes N working ports and 1 protection port. 1 : N can only protect one working channel at the same time, and N working channels share one protection channel. Therefore, protection is generally determined according to priority. Which work channel is the business. Line card A detects the alarm information of port #A-1, line card B detection #B-1 port alarm information and the received Kl, K2 bytes, which are sent to the APS decision module of the main control board through the inter-board communication module. The APS decision module also receives the switching control command issued by the network management device to the protection group of the local device, and the user can set the multiplexing segment 1: the two-way decision mode. When configuring the multiplex section protection group of a certain end device, the user can indicate whether the decision mode of the protection group uses 1-phase or 3-phase, so that the end device is b6-b8 in the K2 byte sent by the protection group. The corresponding value will be filled in.

FIG. 3 is a flowchart of a method for implementing bidirectional linear protection switching of a multiplex section according to an embodiment of the present invention. As shown in FIG. 3, the method includes the following steps:

S10. The node device searches for the configured multiplex section protection group identifier (ID) according to the alarm information or the port that receives the K byte or the switching control, and the node device receives the alarm information and the switching control information, and then sends the APS module to the APS module. Initiating a local bridging request may also directly input this information to the APS module, which is handled by the cost bridging request. S20: The local device compares the local request and/or the remote request in the protection group, and calculates the maximum request with the highest priority in the protection group and the service number of the request; and extracts the request of the peer from the signaling sent by the peer end. For remote requests, the local maximum request is the highest priority bridging request among the bridging requests for all working and protection channels in the local protection group. The local maximum request is calculated when the bridge request of a local channel changes (that is, the alarm information of each channel in the local protection group and the priority comparison of the switching control information are generated), and the remote request receives the opposite end. The signal is extracted from the multiplex section. For details, see G.8131. The request with the highest priority is used to ensure that the two ends perform the same bridge switching on the channel where the request is located. If the highest request is a local request, the request is reported to the opposite end by requesting corresponding signaling (such as SD, SF, etc.); if it is a remote request, the transmitted signaling is RR (reverse request, indicating that it is an acknowledgement Request).

S30. Perform bridging switching according to the received decision mode indicated by K2. Determine the received information of K2, that is, b6-b8, and extract the decision mode information of the peer end from K2. If b6-b8 of receiving K2 is 011, Save the decision mode (mode) to 3-phase, execute the decision according to the standard 3-phase (omitted), and send b2-b8 of K2 to fill in 011, indicating 3-phase, ending;

If the NMS sets the multiplex section 1:N bidirectional decision mode to 1 -phase, if the node device (APS decision module) determines that the decision mode set by the NMS is different from the current decision mode of the node, the report decision mode does not match the information to The network management device is a kind of prompt for the customer, similar to the alarm prompt, and ends. If the K2 indication 1-phase is received, the save execution mode mode is 1-phase, and the process proceeds to step S40. If the receiving K2 indicates other values, the situation of the local setting is judged. If the device is 3-phase, the decision is made according to the standard 3-phase (omitted), otherwise the process proceeds to step S40.

S40. Perform bridging and switching of the service number indicated by the request with the highest priority. If the maximum request is a remote request, go to S50; otherwise, the content of the sending protocol byte is: the request type is the maximum request, the request service number and the bridged service number are both the service number indicated by the maximum request, and b6-b8 indicates 1 in K2. -phase, end;

S50. The content of the sending protocol byte is: the request type is RR (reverse request), the request service number and the bridged service number are both service numbers indicated by the maximum request, and b6-b8 indicates 1-phase in K2. If the management plane sets the multiplex section 1:N bidirectional decision mode to 3-phase, if the node determines that the decision mode set by the network management is different from the local storage decision mode, the report decision mode does not match the information to the network management device, and is for the customer. A hint, similar to an alert, ends. After the decision is made, the result of the bridge switching decision is transmitted to the line card A and the line card B through the inter-board communication module, and the transmission K1 and Κ2 are transmitted to the line card and transmitted through the protection port.

It is irrelevant whether the S50 and 1-phase process sent by the above process is RR. Because the bridge switching is completed at both ends, the RR is still sent, mainly considering that the APS protocol can still be normal when interfacing with the SDH device running the standard protocol. Run, while other regulations only use the 1-phase standard to specify that the last NR is sent.

The introduction of this method can effectively compensate for the following problems on the switching time: 1. The transmission efficiency of the inter-board communication module is low; 2. The decision-making execution efficiency of the APS decision-making module on the main control is low; 3. The execution efficiency of the line card execution action is low. The service switching time is related to the above several. When the number of interactions is reduced, the requirements for other parts can be appropriately reduced.

4 is a schematic diagram of the APS message flow of the multiplex section bidirectional linear protection switching 1-phase according to the present invention. In the process, at least one device of the left and right end node devices is set to a 1-phase mode, and the node device handshake process at both ends B6-b8 in K2 sent during or during protection switching Instructing 1-phase, the protection switching process is as follows: Initially, both ends of the node device send signaling of NR0, 0; when the left-end node device detects that signal 2 is degraded, and calculates the highest priority of the SD bridging request of signal 2, After the bridge switching is completed, SD2, 2 is sent (requesting the peer bridge signal 2); if the right end node device has the highest priority of the bridge request for the acknowledgement signal 2, the bridge switching of the signal 2 is also completed, and RR2, 2 is sent. The latter process is similar.

It can be seen from the above that by transmitting SD2, 2, the bridge switching at both ends is completed, and the switching execution process is simplified. At the same time, the number of APS signaling transmissions is reduced, the corresponding time is also reduced, and the switching efficiency is correspondingly improved.

5 is a schematic flow chart of an APS message of a 1-phase node device and a 3-phase node device of the present invention, assuming that the left end node device is set to 1-phase, and the right end node device is set to an existing node device (existing node) The devices are executed in 3-phase, and the phase is not detected from K2. The protection switching process is as follows: Initially, both ends send NR0, 0 signaling; when the left end node device (press 1-phase, because When the received K2 byte has no indication mode, it is still executed by 1-phase. When the signal 2 degradation (SD) is detected, and the SD bridge request of the signal 2 is calculated to have the highest priority, the bridge switching is completed, so SD2, 2 is transmitted. (Request peer bridge signal 2); Right end node device (because it is the old device, it will not judge the decision mode indicated by K2, but according to the normal 3-phase processing, the received K1K2 is SD2, 2, indicating that the left end requests the right end Bridge signal 2, while the left end has completed signal 2 bridging, then the local end can complete the bridging switching of signal 2) The acknowledgment signal 2 bridging request has the highest priority and is also completed Switching the bridge number 2, transmission RR2,2.

When the right end node device detects signal 3 failure (SF) and calculates the SF bridge of signal 3, please If the priority is the highest, the signal 2 is reversed and the SF3, 2 is sent; the left end device undoes the bridge switching of the signal 2, and completes the bridge switching of the signal 3, transmitting RR3, 3; the right end node device completes the bridge switching of the signal 3. , send SF3, 3; the latter process is similar.

The device of the present invention is well compatible with the original device, and there is no problem of docking. The entire process is degraded to two handshakes to complete the bridge switching, so there is no impact on the switching efficiency.

The 3-phase side refers to the node in which the present invention is implemented in a default 3-phase manner, and the 1-phase side finger is executed in a 1-phase manner using the node of the present invention as shown in FIG. 5, when requested by the 3-phase side At the time of initiation, the entire process degenerates into a 2-phase (two-node interaction between two nodes) execution, and if the request is initiated by the 1-phase side, it is still executed in 1-phase. If B clicks 3-phase to execute, when NR is received instead of RR, it will cause point B to fail to complete the switchover (NR request was originally only used to indicate that there is no request currently, request signal number is 0 or additional service number) .

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module in the foregoing embodiment may be implemented in the form of hardware, or may be implemented in the form of a software function module. The invention is not limited to any specific combination of hardware and software.

The above is only a preferred embodiment of the present invention, and of course, the present invention may be embodied in various other embodiments without departing from the spirit and scope of the present invention. Various changes and modifications may be made to the invention, but such changes and modifications are intended to be included within the scope of the appended claims.

INDUSTRIAL APPLICABILITY The present invention provides a method and a node device for realizing bidirectional linear protection switching of a multiplex section, and reduces the three interactions of protocol bytes in the switching process to one interaction, and the corresponding decision processing is only once, which can greatly improve The multiplexing efficiency of the multiplex section 1:N bidirectional linear protection compensates for the deficiencies of other processing units. Specifically, the implementation of the multiplex section protection decision is optimized, and the requirements for other processing units are correspondingly reduced. For example, after the switching efficiency is increased, the requirements for fast detection of alarms can be reduced accordingly. Usually, the alarms are quickly detected by hardware, which can relatively reduce some parameters of the hardware. At the same time, the announcement phase mode also enhances controllability.

Claims

Claim

A method for implementing a bidirectional linear protection switching of a multiplex section, the method comprising: after the node device calculates a bridging request with the highest priority in the protection group, performing bridging and switching of the bridging request corresponding service according to the first decision mode.

The method of claim 1, wherein: the step of the node device performing bridging and switching of the bridging request corresponding service according to the first decision mode comprises: if the node device determines that the node device is configured first In the decision mode, bridging and switching of the service corresponding to the bridging request is performed.

The method of claim 1, wherein: the step of the node device performing bridging and switching of the bridging request corresponding service according to the first decision mode comprises: if the node device determines the received multiplex section overhead K2 Indicates the first decision mode, and then performs bridging and switching of the service corresponding to the bridging request.

4. The method according to claim 3, wherein: after the step of determining that the received multiplex section cost K2 indicates the first decision mode, the method further includes: saving the first decision After the step of performing the bridging and switching of the bridging request corresponding service according to the first decision mode, the method further includes: sending a multiplexing segment overhead K2 indicating the first decision mode.

The method according to any one of claims 1-4, wherein: in the process of performing the bridging and switching of the bridging request corresponding service according to the first decision mode, the method further includes: the node device If the switching control information sent by the network management system is received, and the decision mode carried by the switching control information is different from the currently executed decision mode, the decision mode mismatch information is reported to the network management.

6. A node device, including at least one working port and one protection port, the working end And the protection port interacts with an automatic protection switching (APS) module, where: the APS module is configured to: after calculating a bridge request with the highest priority in the protection group, performing the bridging request corresponding service according to the first decision mode Bridge and switch.

7. The node device according to claim 6, wherein: the APS module is configured to perform bridging and switching of the bridging request corresponding service according to the first decision mode as follows: if it is determined that the node device is configured first In the decision mode, bridging and switching of the service corresponding to the bridging request is performed.

8. The node device according to claim 6, wherein: the APS module is configured to perform bridging and switching of the bridging request corresponding service according to the first decision mode as follows: if judging the received multiplexing segment overhead K2 The byte indicates the first decision mode, and then the bridging and switching of the service corresponding to the bridging request is performed.

The node device according to claim 8, wherein: the APS module is further configured to: save the first decision mode, and further, after completing bridging and switching, send a multiplexing indicating the first decision mode Segment overhead K2.

The node device according to any one of claims 6-9, wherein: the APS module is further configured to: if receiving the switching control information sent by the network management, and determining the decision mode carried by the switching control information Different from the currently executed decision mode, the decision mode mismatch information is reported to the network management.