WO2007006175A1 - Procede de mise en oeuvre de la prevention des defaillances facile prise en charge par la protection annulaire partagee des canaux - Google Patents

Procede de mise en oeuvre de la prevention des defaillances facile prise en charge par la protection annulaire partagee des canaux Download PDF

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Publication number
WO2007006175A1
WO2007006175A1 PCT/CN2005/001016 CN2005001016W WO2007006175A1 WO 2007006175 A1 WO2007006175 A1 WO 2007006175A1 CN 2005001016 W CN2005001016 W CN 2005001016W WO 2007006175 A1 WO2007006175 A1 WO 2007006175A1
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Prior art keywords
node
channel
service
protection
state
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PCT/CN2005/001016
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English (en)
French (fr)
Inventor
Zhenyu Wang
Xiaoqiang Wei
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Zte Corporation
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Priority to PCT/CN2005/001016 priority Critical patent/WO2007006175A1/zh
Publication of WO2007006175A1 publication Critical patent/WO2007006175A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/08—Intermediate station arrangements, e.g. for branching, for tapping-off
    • H04J3/085—Intermediate station arrangements, e.g. for branching, for tapping-off for ring networks, e.g. SDH/SONET rings, self-healing rings, meashed SDH/SONET networks
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation
    • H04J14/0241—Wavelength allocation for communications one-to-one, e.g. unicasting wavelengths
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0278—WDM optical network architectures
    • H04J14/0283—WDM ring architectures
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0287—Protection in WDM systems
    • H04J14/0289—Optical multiplex section protection
    • H04J14/0291—Shared protection at the optical multiplex section (1:1, n:m)
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J14/00—Optical multiplex systems
    • H04J14/02—Wavelength-division multiplex systems
    • H04J14/0227—Operation, administration, maintenance or provisioning [OAMP] of WDM networks, e.g. media access, routing or wavelength allocation

Definitions

  • the invention relates to an implementation technology of channel sharing ring protection in an optical fiber transmission network, in particular to a technology for implementing protection switching and error correction of channel sharing ring protection in a ring optical transmission network using wavelength division multiplexing technology.
  • the ring network structure has been widely recognized by the industry for its good self-healing capability.
  • the type of ring network protection has been continuously enriched and improved, and it has been more and more widely used in practical engineering.
  • Ring network protection technology is one of the important components of APS (Automatic Protection Switching) technology. Its implementation method and technology are also in the process of continuous development.
  • the International Telecommunication Union Telecommunication Standardization Sector has issued a series of standard recommendations for optical network protection technologies: G. No. 841, "Types and Characteristics of SDH Network Protection Architecture" is mainly for SDH light.
  • the network's automatic protection switching technology has made specific recommendations.
  • the protection of the ring network only covers the implementation of the multiplex section shared ring protection switching and error-blocking technology, but does not include the channel shared ring protection commonly used in current optical networks. Technical content. G. 808. Recommendation No. 2
  • the ring network protection principle is proposed, but the principle of the protection switching technology basically follows the provisions of Recommendation G. 841.
  • the implementation scheme of the channel shared ring protection mode proposed by the present invention has the advantages of flexible service switching and high network resource utilization rate.
  • the channel shared ring protection switching in the optical network if the socket uses the principle of multiplex section shared ring protection in the G. 841 protocol, the channel shared ring protection cannot be effectively implemented.
  • the main reason is: multiplex section shared ring
  • the principle of the protection protocol processing is to perform double-end switching on the adjacent nodes at both ends of the fault to form a new loop.
  • the protection granularity can directly correspond to the service, it can be The upstream node and the downstream node of the service directly perform double-ended switching to form a new loop, which avoids forming a long overlapping loopback loop like the multiplex section ring protection.
  • the business of fault protection for ring network protection most of the industry is based on the existing industry standards, first to determine the situation where the service may be connected in error, and then to implement the business error correction processing by shutting down the service device of the service.
  • the method is a feasible method for the ring network sharing protection (including the two-fiber unidirectional/bidirectional ring sharing protection/four-fiber bidirectional ring sharing protection, etc.), but for the channel-wide ring sharing protection application. In this way, the error-resistance processing method of shutting down the service sender device is not an optimal implementation technique.
  • the service error prevention technology can only be implemented based on the result of the switching operation, for example, as shown in FIG. 2, when the ring network spans When there is a fault in both the 3 and the span 5, the service T1 in the CD direction on the faulty node C is switched to the protection path in the CB direction, and the node F is affected by the span 5 fault.
  • the service T2. is switched to receive the signal from the protection path in the GF direction. Therefore, due to the principle of sharing the protection channel, the signal sent by the service T1 is misconnected to the service ⁇ 2, and the transmission terminal of the service T1 needs to be turned off. 'Prepare to suppress the wrong connection situation.
  • This kind of error prevention method involves opening/closing the service sending equipment. There are also potential risks when the processing is complicated.
  • the service protection processing can be implemented in the same way as the shared-ring protection type of the multiplex section.
  • the channel-sharing protection can directly implement the switching of the protected service on the switching principle. While having the characteristics of sharing protection resources, the invention also has the feature of achieving high efficiency switching based on the business up and down situation, and accordingly, the present invention proposes a method for implementing the business error correction processing more easily.
  • the technical problem to be solved by the present invention is to provide a method for implementing channel sharing ring protection that supports simple error rectification, and solves the problem of overlapping loopback loop formed by double-end switching of adjacent nodes at both ends of a fault span. technical problem.
  • Another technical problem to be solved by the present invention is to provide an implementation method of a channel shared ring protection that supports simple error prevention, which is characterized in that, in a ring network, a fault occurs across a working path.
  • the service directly performs double-end switching on the uplink node and the downlink node of the service working path to form a protection path avoiding the fault span.
  • the above method is characterized in that, for the service path and the protection path in the ring network, there is a fault spanning service, and the channel protection state of the upper and lower road nodes of the service is changed to the channel idle state, thereby canceling the previous possibility.
  • the switching operation that occurs can avoid the situation of causing business misconnection without shutting down the service sending device, and realizes simple error prevention.
  • the automatic protection switching module that supports the channel sharing ring protection switching is downloaded to the automatic protection switching control board of each node in the ring network; in the switching module, corresponding to the ITU-T G.841 protocol
  • the specified three states of the idle state, the through state, and the reverse state are introduced into the channel switching state, the channel through state, and the channel idle state.
  • the channel switching state corresponds to the local need to protect the service signal in the work switching and protection.
  • the channel through state corresponds to an operation of connecting the local protection channel
  • the channel idle state corresponds to the normal operation of the local service signal by the working channel;
  • the protection group information is downloaded and stored in the local database of the control board.
  • Step 3 In the case where there is no fault span, the node status of each node is idle. After the fault span occurs, according to the processing principle of the APS protocol, the automatic protection switching signaling passes between the ring nodes. After the response is stabilized, the node states of the adjacent nodes on the fault span are in a reverse state, and the switch direction is the adjacent side of the fault span, and the node states of the other nodes are the through state.
  • Step 4 According to the node status and the received APS signaling, combined with the protection group information, determine whether the protected service is affected by the fault span, thereby further determining the channel protection status of each node: the service affected by the fault
  • the channel protection state of the upper and lower nodes is the channel reversal state, and the switching operation of the adjacent side of the working path is performed;
  • the channel protection state of the node on the protection path of the service affected by the failure is the channel through state, and the protection channel is required to be punched through. Operation;
  • the channel protection state of the adjacent nodes of the fault span is the channel idle state;
  • the channel protection state of the remaining nodes is the channel through state, and the protection channel punch-through operation needs to be performed;
  • Step 5 On the basis of the previous single-span fault, for each additional fault span, it is necessary to re-observe the node protection state after each node protocol response is stable according to the APS protocol;
  • Step 6 after obtaining the state of the node in the case of multi-span failure, according to the state of the node and the For the protection group information, the uplink and downlink services of each node of the network need to be processed as follows: For the service where the working path and the protection path are faulty at the same time, the channel switching state of the service node and the downlink node should be the channel. In the idle state, the switching operation that may have occurred before is cancelled. For the service that only has a fault in the working path, the channel switching state of the service node and the downstream node should be the channel switching state, and the switching operation of the adjacent side of the working path is performed. The node on the service protection path is in the channel pass-through state. For the service where only the protection path is faulty, that is, the service path is not faulty, the channel switching state of the service on the upper and lower nodes should remain in the original state, and no need to be performed. New switching operation.
  • the determining whether the service of each node is affected by the fault includes: for the node in the through state, according to the service configuration type, and determining the service on the node by the node Is the downstream node in the counterclockwise direction farther than the source node from the clockwise direction signaling, and whether the upstream node of the service at the local node is in the counterclockwise direction is closer to the counterclockwise direction signaling The way the source node is to determine if the node's service is affected by the failure.
  • the determining whether the service of each node is affected by the fault includes: for the node in the reverse state, according to the switching direction of the node and the type of the service Determine the channel protection status of the node.
  • the above method is characterized in that, after the fault section is repaired, the node state is changed from the through state 3 ⁇ 4 ⁇ switching state to the idle state, and the channel protection state of the node is also changed to the channel idle state.
  • the protection group information includes: a self-attribute of setting a protection configuration in the network, physical address information related to the monitor and the executor, network topology information, and a related node Protected business configuration information.
  • the self-attribute includes: a return mode, a wait recovery time, a fault-blocking enable state, and a signal degradation protection defined in the ITU-T standard; : Service configuration type, on-route node, and drop-down node.
  • the present invention provides a method for implementing channel sharing ring protection that supports simple error rectification.
  • the channel sharing ring protection directly corresponds to the service in the protection granularity, and the double-ended switching directly forms a new ring in the service node and the downstream node of the service.
  • the road is no longer the same as the multiplex section ring protection.
  • the two-end switchover is performed on the adjacent nodes at both ends of the fault. This avoids the formation of a long overlapping loopback loop.
  • the channel shared loop protection is more flexible and economical.
  • FIG. 1 is a schematic diagram of a protection principle of a shared loop protection of a two-fiber multiplex section and a shared loop protection of a two-fiber channel when a D-E span fails in a ring network;
  • FIG. 2 is a schematic diagram of a service misconnection situation caused by ring network shared protection switching in the case where both C-D and E-F are in the same fault condition in the prior art;
  • FIG. 3 is a schematic diagram of a two-fiber channel shared ring protection transmission system
  • Figure 4 is a flow chart of node APS processing
  • Figure 5a is a schematic diagram of the operation of the uplink service
  • Figure 5b is a schematic diagram of the operation of the downlink service
  • Figure 5c is a schematic diagram of the operation of the upper and lower roads
  • Figure 5d is a schematic diagram of the operation of the through service
  • Figure 6 is a flow chart of the channel protection process with the node status PASS;
  • Figures 7a-7g are schematic diagrams of different protection scenarios for channel sharing rings
  • Figure 8 is a flow chart of the channel protection process with the node status SWITCH; ⁇ . . . , :::
  • Figure 9 is a schematic diagram of the protection of the two-fiber channel shared ring when the C-D span is faulty in the ring network.
  • Figure 10 shows the protection of the two-fiber channel shared ring when the C-D span and the E-F span are faulty in the ring network;
  • Figure 11 is a schematic diagram of protection of two-fiber channel shared ring when there is a fault in the C-D span, E-F span, and H-A span in the ring network. The best way to achieve the invention
  • the present invention is a technique for implementing protection switching and squelching/prevent misconnections of a channel shared ring protection in a ring optical transmission network using Wave Division Multiplexing (WDM) technology.
  • WDM Wave Division Multiplexing
  • the invention provides an implementation method of channel sharing ring protection for supporting simple error rectification in an optical network, which mainly includes two aspects: Firstly, a protection switching implementation method for performing switching according to the channel service of the channel service is proposed; secondly, The invention is implemented by adopting a new channel sharing ring protection protection In the current method, the switching operation in the case where the service may be misconnected is appropriately adjusted, and the service error-correcting processing can be realized without shutting down the service transmitting device without affecting the protection function, which can effectively eliminate the error-inducing service. The potential risk of sending device switching operations.
  • the process of the channel shared ring protection method for supporting simple error rectification adopted by the present invention is:
  • the APS software that supports the channel shared ring protection switching is downloaded to the APS control board of each node to which the ring optical network belongs.
  • three channel protection states are introduced based on the three states of the idle state (IDLE), the through state (PASS), and the reverse state (SWITCH) in the ITU-T protocol: Channel switching states ( CSWITCH), channel pass-through state (CPASS) and channel idle state (CIDLE).
  • the channel switching state corresponds to the switching operation between the service switching and the protection channel, and the channel direct state corresponds to the operation of connecting the local protection channel;
  • the channel idle state corresponds to the local service signal being normally up and down by the working channel. operating.
  • the channel protection status is further derived from the local service configuration and network topology information based on the node status.
  • the protection group configuration of the channel sharing ring protection type is performed through the network management.
  • the protection group information is downloaded as protection configuration information and stored in the database of the APS control board.
  • the meaning of the protection group refers to the self-attribute of a certain protection configuration in the network (return mode, waiting for recovery (WTR) time, error-blocking enable state, signal degradation protection, etc. defined in the ITU-T standard), Logic related to the physical address information of the monitor and the executor, the network topology information, and the protected service configuration information (including the service configuration type (Operation), the add-on node (AddNode), and the drop node (DropNode)) set.
  • the state of each node in the ring network is idle.
  • a certain span M fails (for a signal failure situation detected by the service receiving device, it can be attributed to a fault in the service working path adjacent to the service downlink node), according to the processing principle of the APS protocol, the APS letter
  • the node obtains a new state value: the nodes on the adjacent sides of the fault span are in a reverse state, and the other loop nodes are in a through state.
  • the nodes adjacent to both ends of the segment 3 the node state of D is the reverse state, and the node state of the other nodes is the through state.
  • the implementation process of the APS protocol is mainly implemented by the response process of the APS signaling.
  • the communication mode of the APS signaling may include multiple (such as byte stream mode and IP packet mode), and the following is defined in the TU-T standard.
  • the K1/K2 byte mode is described as an example. After an APS signaling response process reaches a steady state, the K bytes received by each node will not change. At this time, the received K byte must be from the current node. The most recent fault is sent across the adjacent nodes.
  • the definition of K bytes according to the ITU-T standard shown in Table 1 and Table 2 (the format of IP packet signaling can be more flexible than K bytes, but should include K bytes.
  • the identifier of the K-byte source node can be extracted in the ⁇ byte, so that the position of the fault span in the ring network can be obtained according to the K byte.
  • the APS protocol is triggered by the fault of the segment 4.
  • the source node of the K-byte counterclockwise direction received by the node A is E, and the received outer ring direction K word.
  • the source node of the section is D.
  • APS request command code (1 to 4 digits) Destination address ID (5-8 digits) 2-byte structure definition: Source address ID (1-4 digits) (6-bit) APS status (6-8 bits)
  • node status and ring network service configuration information service uplink and downlink nodes, ring network topology, etc.
  • the protection status of the upper and lower nodes of the service affected by the fault is the channel reversal state, affected by the node on the service protection path is the channel through state, and the other nodes are the channel idle state, and according to this ⁇
  • the state value determines the corresponding protection switching action.
  • the channel protection protection state of the upper and lower nodes C, E of the service T1 changes to the pass:: the channel reversal state, the service T1 protection path
  • the channel protection state of the node (B, A, H, G, F) is the channel pass-through state
  • the channel protection state of the intermediate node D on the service T1 working path is the channel idle state.
  • the present invention identifies the current normal working path and the protection path of the current service by combining the local service configuration and the network topology information with the APS protocol processing process between the network nodes.
  • the reverse state of the upstream and downstream nodes of the original service is immediately updated to the idle state, so that the misconnected service may be switched back to the original normal working path, thus eliminating the business misconnection phenomenon. It will not affect the protection function of the network. And according to the state value, the corresponding protection switching action is determined.
  • the final channel protection status should be based on the judgment of the affected service. If the uplink service and the downlink service are affected at the same time, the channel protection status of the node should obviously be the channel. Idle state.
  • the channel protection status of the upper and lower nodes corresponding to the service should be determined as follows: for all the services affected by the faults of the M, N, and Q faults in the network are determined as follows: If the working path and the protection path of the service are both faulty, the channel protection status of the upper and lower nodes corresponding to the service should be If the working path is faulty, the protection status of the upper and lower nodes of the service affected by the fault is the channel reversal state, and the nodes on the affected service protection path are channel pass-through state, and other nodes are channel idle state; If only the protection path is faulty, the node channel status should remain the same. Based on this status value, the corresponding protection switching action is determined.
  • the final channel protection status should be based on the judgment of the affected service. If the on-line service and the off-line service are affected by the elbow, The channel protection state of the node should obviously be the channel idle state. ⁇
  • the present invention is a method for implementing channel sharing ring protection in a ring optical network that supports simple error rectification.
  • the important feature is that the channel sharing ring protection directly corresponds to the service in the protection granularity, and is directly at the service node and the downstream node of the service. Double-end switching is performed to form a new loop. The double-ended switching between adjacent nodes at both ends of the fault is not used in the same way as the multiplex section ring protection. This avoids the formation of a long overlapping roundabout loop and channel sharing.
  • the implementation of the ring protection is more flexible and economical.
  • the network protection capability can be adjusted by adjusting the switched node to the idle state for the service fault-correction processing in the case of network double-span and multi-span faults. On a constant basis, it realizes the function of easily blocking faults without shutting down the service sending device.
  • Figure 3 depicts an example of a simple optical network transmission network structure.
  • Each light includes multiple channels, and each channel can carry one path.
  • Service signal; node corresponds to the station.
  • the optical signal is transmitted in the opposite direction.
  • a two-fiber unidirectional/bidirectional multiplex section shared ring protection can be supported, or multiple two-fiber unidirectional/bidirectional channel shared ring protection type protection configurations can be simultaneously supported.
  • the outer ring can also be completely peer-to-peer for service configuration, but the protection switching principle is basically the same.
  • Figure 4 depicts the basic flow of the APS process of the present invention. The figure includes the following steps:
  • Step 401 the system starts, and the network management configures APS data information.
  • Step 402 A node APS controller receives a network management command/detection board detects a fault/receives new APS signaling;
  • Step 403 generating and outputting APS signaling, respectively, to the two ends of the ring, until the system APS signaling response is stable, and obtaining a new node state;
  • Step 404 Determine, according to the node status and the protection service information, the channel protection status according to the service protection and the error protection requirement, and further determine the protection switching action.
  • Step 405 Send a protection switching action command to the APS execution board, and return to step 402.
  • the APS process is as follows: First, the APS software is downloaded to the APS control board. After the power is turned on, the APS configuration data information is sent through the network management system. When a certain span occurs, the APS detection board of the downstream adjacent node of the span: detects the fault, and the fault information is sent to the APS control board to start a new APS process.
  • the APS control board can also initiate a new APS process by receiving the manually issued network management command.
  • the node receives the new APS signaling, indicating that a new APS process has been initiated by other nodes in the ring. The beginning of the node APS process.
  • the APS control board processes the new APS signaling according to the protocol, and then sends the new APS signaling to the peer node through the long and short paths of the ring, so that the nodes in the entire ring perform repeated APS letters. Let the response stabilize.
  • the node After processing each APS signaling change, the node will first determine the new node status, and then further process according to the node status and protection service information to determine the channel protection status, and then determine the switching action and send it to the APS for execution. veneer. At this point, a complete APS process is completed and the system returns to wait for the next APS process.
  • the main means for the APS to effectively process the channel sharing ring is to protect the service information and the network topology information, and the service information mainly includes the configuration type (operation) and the uplink node (AddNode). ), the down node (DropNode).
  • the service information mainly includes the configuration type (operation) and the uplink node (AddNode). ), the down node (DropNode).
  • the service configuration type of the node it is determined that a certain direction of the ring (clockwise or counterclockwise) is used as the reference direction.
  • the counterclockwise direction is used as the reference direction, and the distance between the two nodes to be used later with respect to the current node is also based on the counterclockwise direction.
  • the on-going node referred to here refers to the on-going node of the current node's downlink service; the downlink node refers to the downstream node of the current node's on-off service.
  • the definition of the protection service configuration type will be described below with reference to Figures 5a, 5b, 5c, and 5d.
  • the next node is (:, the node on the road is B.
  • the service on the working channel in the counterclockwise direction is from the node A and the node B, and there is an intermediate node in the middle, and the node B is in the middle.
  • the configuration type of the B node is defined as "downward” or "drop”; the upper node is A, and the lower node is B.
  • the counter-clockwise working channel of the node B is If there is a service under the road and there is another service on the road, the configuration type of the B node is defined as "up and down" or "
  • the service information mentioned here is not specific to one service, but is a comprehensive information of services for the working channel of the ring.
  • the node status of each node on the ring is determined: In the case of a fault, the status of the adjacent node of the fault span is SWITCH (the direction of the switch is the direction of the adjacent side of the fault span), and the fault span The status of the nodes that are not adjacent to the segment is PASS. However, when the node is isolated, that is, the nodes on both sides of the node fail at the same time, the state of the node is IDLE; the node state when the system recovers after the fault is repaired is IDLE.
  • the node protection status of the node can be finally determined by the node status of the current node, the service information of the working channel, the information of the APS signaling source node, and the node sequence information of the ring network. Further, wherein the node state is divided into three cases. (1) The process of node status is PASS
  • the node C is the current node.
  • the service is on the way from the current node C, and the node F is on the way; the source node of the APS signaling from the outer ring direction received by the node C is the node D.
  • the channel protection state is set to the channel switching state (CSWITCH);
  • the right channel switch is switched.
  • the service is from the current node C, and the node D is on the way; the source node of the APS signaling from the outer ring direction received by the node C is the node D.
  • the channel protection state is set to the channel pass state (CPASS). ; No switch switching is required.
  • the node F is the current node.
  • the service is on the node C, and the current node F is on the way; the source node of the APS signaling from the counterclockwise direction received by the node F is the node E.
  • the channel protection status is set to the channel switching state (CSWITCH); On the left side of the current node (in the direction of the service), the left channel switch is switched.
  • the service is from the node E, and the current node F is on the way; the source node of the APS signaling from the counterclockwise direction received by the node F is the node E.
  • the channel protection state is set to the channel pass state (CPASS); No switch switching is required.
  • the corresponding processing can be decomposed into two sub-processes with the service configuration types of Add and Drop respectively. After processing the two sub-processes according to the above method, the two results are merged. , you can get the channel protection status and switching action.
  • CPASS performs protection channel punch-through operation.
  • the node status of the adjacent node E on the right side of the fault span 4 should be SWITCH, and the node switching direction is left.
  • the service configuration type of the E node is Add. Since no service is affected by the fault spanning, the channel protection status should be CIDLE and there is no switching action.
  • the node status of the adjacent node E on the right side of the fault span 4 should be SWITCH, and the node switching direction is left.
  • the service configuration type of the E-node is Drop. Since the service is bound to be affected by the fault span, the channel protection status should be CSWITCH.
  • the fault span is located on the left side of the current node (in the service direction). Switched.
  • the node status of the adjacent node E on the right side of the fault span 4 should be SWITCH, and the direction of node switching is left.
  • the service configuration type of the E-Node is Pass. Because the channel shared ring sharing protection of the present invention is only performed on the service uplink and downlink nodes, the channel protection status is CIDLE, and channel switch switching is not required. Also, since the service switching does not pass through the protection channel of the D node, there is no need to protect the channel through. Therefore, the D node does not need channel switch switching.
  • the node status of the adjacent node D on the left side of the fault span 4 should be SWITCH, and the node switching direction is right.
  • the service configuration type of the D node is Add. Because the service is in any way, it will be affected by the fault span. Therefore, the channel protection status should be CSWITCH, because the fault span is located on the right side of the current node. Direction), the right channel switch is switched.
  • the node status of the adjacent node D on the left side of the fault span 4 should be SWITCH, and the node switching direction is right.
  • the service configuration type of the D node is Drop. Since no service is affected by the fault spanning, the channel protection status should be CIDLE and there is no switching action.
  • the configuration type of the node D is AddDrop, combined with the above (25), (26) analysis, the downlink service of the node will not be affected by the fault, and the traffic on the node will inevitably be affected by the fault, so the processing conclusion is the same as (25):
  • the channel protection state should be CSWITCH, due to The fault span is located on the right side of the current node (in the service direction), and the right channel switch is switched.
  • the node status of the adjacent node D on the left side of the fault span 4 should be SWITCH, and the node switching direction is right.
  • the service configuration type of the D-node is Pass. Because the channel shared ring sharing protection of the present invention is only performed on the service uplink and downlink node, and the adjacent nodes of the fault span do not need to be punched through, the channel protection state is CIDLE, and channel switch switching is not required. Also, since the service switching does not pass through the protection channel of the E node, the E node does not need PASS.
  • the node status of the adjacent node E on the right side of the fault span 4 should be SWITCH, and the node switching direction is left.
  • the service configuration type of the E-node is Null. Because the channel shared ring sharing protection of the present invention is only performed on the service access node, and the adjacent nodes of the fault span do not need to be punched through, the channel protection status is CIDLE, and no channel switch switching is required.
  • node status PASS or SWITCH it is the protection process after the network detects the fault. After the fault repaired service, the reply from the protection path to the working channel is the necessary content of the APS. The network detects that the fault disappears, and then the entire APS. The system responds by signaling, and the stable node shape: the state will be from the original PASS or SWITCH. Go back to the IDLE state.
  • the determination of the state of the node to the IDLE is relatively simple, and no special judgment is required: the channel protection state is CIDLE, and the channel switch state is non-switching state.
  • the channel sharing protection switching operation can be determined, and the APS control board sends the switching command to the APS execution board to perform the corresponding APS switching operation.
  • FIG. 9 is a schematic diagram of the protection principle of the two-fiber channel shared ring protection when the CD span in the ring network is faulty.
  • the faulty neighboring nodes C and D respectively detect the fault, and initiate APS signaling to the respective peer node respectively.
  • each node of the network Analyze the received signaling content separately, and combine the locally stored network topology information to obtain a single span of the fault (span 3), and then combine the local service configuration information to determine whether the local uplink/download service crosses the fault.
  • Segment if the local up/down traffic is affected by the fault, execute the phase
  • the switching operation should be reversed; otherwise, the through state is maintained; for the node that is not configured to be up/down in the local state, no operation is required and remains in the idle state.
  • the upper and lower nodes C and E of the service T1 are changed from the original idle state to the switched state (the C node is the right switchover and the E node is the left switchover), and the service T1 is switched from the normal pass channel to the protection. channel. Since the service T2 is not affected by the fault, no corresponding switching operation is performed.
  • the protection switching process in the case of a single-span failure is described in Section 5.1.
  • Figure 10 is a schematic diagram of the protection principle of the two-fiber channel shared ring protection when the E-F span fails again after the C-D span occurs in the ring network.
  • the cross-segment 5 is faulty again. If the new affected service T2 is switched in the same manner as the cross-segment 3, the double-end switching of the similar service T1 occurs. This will lead to a misconnection of the ring network business.
  • the approach proposed for this invention is:
  • each node determines the occurrence of the network fault according to the received APS signaling (for details of the decision process, refer to the description in Section 5.1). Finally, each node can determine that the fault occurs in C according to the received APS signaling. - D spans section 3 and EF spans section 5.
  • the original channel switching state of the node E should be changed to the channel idle state immediately, and the original channel straight-through state of the node F should be The change is the channel idle state, and will not be switched due to the E-F span fault, achieving the purpose of simple error prevention.
  • the channel protection state is maintained.
  • the original state does not require a new protection switching action.
  • the channel protection state remains in the channel idle state.
  • Figure 11 shows that the AH span 8 occurs again on the basis of the double-span fault shown in Figure 10 in the ring network.
  • the situation of the failure According to the method proposed by the present invention, the process is implemented as follows:
  • each node determines the occurrence of the network fault according to the received APS signaling (for details of the determination process, refer to the description in Section 5.1). Finally, each network node can analyze the network fault occurrence as follows: For node D, E, can determine that there is a fault between span 3 and span 5; for nodes F, G, H, it can be judged that span 5 and span 8 fail; for node 8, (, can determine span 3 and span Segment 8 has failed.
  • the channel protection status of the node G, H. is not affected (the node G maintains the original channel through state; the node H has the service T3 and T4 at the same time, and the channel protection should be determined according to the judgment of the service ⁇ 4 affected by the failure.
  • the status is the channel idle state). For nodes A and D that do not have local uplink/download traffic, the channel protection state remains in the channel idle state.
  • the channel sharing ring protection directly corresponds to the service in the protection granularity, and the double-ended switching is directly performed on the upper node and the lower node of the service to form a new loop, and the fault is no longer used in the same manner as the multiplex section ring protection.
  • Double-end switching between adjacent nodes at both ends of the segment avoids forming a long In the overlapping loopback loop, the implementation of the channel shared loop protection is more flexible and economical.
  • the switched node can be adjusted to idle.
  • the state mode realizes the function of simply blocking the transmission without turning off the service transmission device.
  • the method of the invention is suitable for protection switching and error blocking of channel sharing ring protection in a ring optical transmission network using wavelength division multiplexing technology, and the method of the invention is also suitable for other optical fiber transmission networks, and other similar applications exist. field.

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Description

一种支持简易阻错的通道共享环保护的实现方法 技术领域
本发明涉及一种光纤传输网络中通道共享环保护的实现技术， 特别涉及采 用波分复用技术的环形光传输网中通道共享环保护的保护倒换和阻错的实现 技术。 背景技术
在目前的光纤传输网络中， 环形网络结构以其良好的自愈存活能力已经得 到了业界的普遍认同。随着环网保护技术的不断发展，环网保护类型得以不断 丰富完善， 已经在实际工程中得到越来越广泛的应用。
环网保护技术作为自动保护倒换 （简称 APS， Automatic Protection Switching)技术的重要组成内容之一， 其实现方法和技术也处于不断发展完 善的过程中。国际电信联盟电信标准分会（International Telecommunication Union Telecommunication Standardization Sector)先后发布了一系列有关 光网络保护技术的标准建议： G. 841号建议《SDH网络保护体系结构的类型和 特性》中对主要针对 SDH光网络的自动保护倒换技术做出了具体的建议，其中 关于环形网络的保护只涵盖了复用段共享环保护倒换及阻错技术的实现，而没 有包括当前光网络中常采用的通道共享环保护的技术内容。 G. 808. 2号建议
(目前尚未正式发布）主要针对 0TN光网络应用情形对环网保护原理提出了建 议，但是保护倒换技术的原理方面基本沿用 G. 841号建议的规定。本发明提出 的通道共享环保护方式的实现方案，具备针对业务灵活倒换、高网络资源利用 率等优点。
对于光网络中通道共享环保护倒换的实现， 如果 ：接套用 G. 841协议中复 用段共享环保护的原理，将不能够高效地实现通道共享环保护，主要原因在于： 复用段共享环保护协议处理的原理是对故障跨段两端相邻的节点进行双端倒 换以形成一个新的环路；而对于通道共享保护来说， 由于在保护粒度上可直接 对应到业务，因而可以在业务的上路节点和下路节点直接进行双端倒换形成新 的环路，避免了同复用段环保护一样形成一个较长的重叠的迂回环路。例如图 1所示， 当节点 D和 E之间的跨段发生故障时， 虚线所示的从节点 C到节点 F 的逆时针环工作业务 TO应倒换到如点划线所示的外环路径上， 而不是如虚线 所示的冗余路径。很显然，业务的上下路节点并不一定是与故障跨段直接相邻 的节点，所以决定了通道共享环保护需要一种新的更加灵活和节约的方法来实 现。
对于环网保护的业务阻错的处理方式， 业界大多数是根据现有行业标准， 首先判断业务可能错连的情形发生，然后通过关断业务发送端设备的方式实现 业务阻错处理， 这种方式对于环网共享保护 （具体包括两纤单向 /双向环共享 保护 /四纤双向环共享保护等类型） 阻错实现来说是一种可行的方法， 但是对 于通道粒度的环共享保护应用来说，这样通过关断业务发送端设备的阻错处理 方式并不是一种最佳的实现技术。由于复用段环共享保护是一种完全基于资源 进行保护倒换的实现方式，所以业务阻错技术只能建立在倒换操作结果的基础 上加以实现， 例如图 2所示， 当环网中跨段 3和跨段 5同时存在故障时， 受跨 段 3故障影响故障节点 C上路沿 C-D方向的业务 T1倒换到 C-B方向的保护路 径， 同时受跨段 5故障影响节点 F下路接收来自 E-F方向的业务 T2.倒换为接 收来自 G-F方向的保护路径的信号，这样由于共享保护通道的原理造成了业务 T1发送的信号错连到业务 Ϊ2接收的可能， 此时需要关断业务 T1的发送端设， '备来压制错连情形发生， .这种阻错方式涉及到对业务发送设备的打开 /关断处,; 理， 处理比较复杂的同时， 也存在着潜在的风险。对于通道共享环保护类型的 应用，也可以通过同复用段共享环保护类型相同的方式实现业务阻错处理，但 是通道共享保护在倒换原理上能够直接针对保护的业务上下情形实现倒换，所 以在具备共享保护资源的特点的同时，还具有基于业务上下路情形实现高效率 倒换的特点， 据此本发明提出了一种能够更加简易实现业务阻错处理实现方 法。 发明公开
本发明所要解决的技术问题是提供一种支持简易阻错的通道共享环保护 的实现方法，解决现有技术因对故障跨段两端的相邻节点进行双端倒换而形成 的重叠迂回环路的技术问题。
本发明所要解决的另一个技术问题是提供一种支持简易阻错的通道共享 环保护的实现方法， 其特点在于，在环形网中， 对于工作路径出现故障跨段的 业务，直接在该业务工作路径的上路节点和下路节点进行双端倒换，形成避开 所述故障跨段的保护路径。
上述的方法， 其特点在于， 对于所述环形网中工作路径和保护路径均存在 故障跨段的业务， 将该业务的上、 下路节点的通道保护状态转为通道空闲态， 从而取消先前可能发生的倒换操作，在不关断业务发送设备的条件下避免引发 业务错连的情形， 实现简易阻错。
上述的方法， 其特点在于， 进一步包括如下步骤：
歩骤一， 将支持通道共享环保护倒换的自动保护倒换模块下载到所述环形 网中每个节点的自动保护倒换控制单板内； 在所述倒换模块中对应 ITU - T G. 841协议中规定的空闲态、 直通态和倒换态三种节点状态引入通道倒换态、 通道直通态和通道空闲态三种通道保护状态：所述通道倒换态对应将本地需要 保护的业务信号在工作倒换和保护通道间的切换操作，所述通道直通态对应将 本地保护通道连通的操作，所述通道空闲态对应本地业务信号由工作通道正常 上、 下的操作；
步骤二， 通过网管将保护组信息作为保护配置信息下载并存储到所述控制 单板的本地数据库中。
步骤三， ·在没有故障跨段条件下， 每个节点的节点状态都是空闲态， 在岀 现故障跨段后，依照 APS协议的处理原理， 自动保护倒换信令通过在环节点之 间相互应答直至稳定后，所述故障跨段相邻两侧节点的节点状态为倒换态，且 倒换方向为故障跨段相邻侧方向， 其它节点的节点状态为直通态。
步骤四， 根据节点状态和接受的 APS信令， 并结合所述保护组信息， 判断 被保护业务是否会受到故障跨段的影响，从而进一步确定出各节点的通道保护 状态： 受故障影响的业务的上、下路节点的通道保护状态为通道倒换态， 执行 工作路径相邻侧的倒换操作；受故障影响的业务的保护路径上的节点的通道保 护状态为通道直通态，需要执行保护通道穿通操作；故障跨段相邻节点的通道 保护状态为通道空闲态；其余节点的通道保护状态为通道直通态，需执行保护 通道穿通操作；
步骤五， 在前面单跨段故障的基础上， 对于每增加的一个故障跨段， 都需 要重新按照 APS协议得出每个节点协议应答稳定后的节点保护状态；
步骤六， 在得出多跨段故障情形下的节点状态后， 再根据节点状态和所述 保护组信息， 对网络的每一个节点的上、下路业务均需做如下处理： 对于工作 路径和保护路径同时存在故障的业务，则在该业务上、下路节点的通道倒换状 态应该为通道空闲态，撤销先前可能已经发生的倒换操作；对于仅仅工作路径 存在故障的业务，则在该业务上、下路节点的通道倒换状态应该为通道倒换态， 执行工作路径相邻侧的倒换操作， 该业务保护路径上的节点处于通道直通态； 对于仅仅保护路径存在故障即工作路径没有故障的业务，则该业务在其上、下 路节点的通道倒换状态应该保持原有的状态， 不需执行新的倒换操作。
上述的方法， 其特点在于， 在所述步骤四中， 所述确定出各节点的业务是 否受到故障影响包括： 对于处于直通态的节点， 根据业务配置类型， 并通过判 断在本节点上路的业务的下路节点沿逆时针环方向是否远于来自顺时针环方 向信令的源节点，以及在本节点下路的业务的上路节点沿逆时针环方向是否近 于来自逆时针环方向信令的源节点的方式，来确定该节点的业务是否受到故障 影响。
上述的方法， 其特点在于， 在所述步骤四中， 所述确定出各节点的业务是 否受到故障影响包括：对于处于倒换态的节点，根据节点的倒换方向和业^ ^配' 置类型来确定该节点的通道保护状态。
上述的方法， 其特点在于， '故障跨段被修复后， 节点状态由直通态 ¾ ^倒换 ') 态转变为空闲态， 节点的通道保护状态也转变为通道空闲态。
上述的方法， 其特点在于， 所述步骤二中， 所述保护组信息包括： 网络中 设定保护配置的自身属性、涉及监测器和执行器的物理地址信息、网络拓扑结 构信息和本节点相关的被保护业务配置信息。
上述的方法， 其特点在于， 所述自身属性包括: ITU-T标准中定义的返回 方式、等待恢复时间、阻错使能状态和信号劣化保护； 所述本节点相关的被保 护业务配置信息包括： 业务配置类型、 上路节点和下路节点。
本发明的优点在于：
本发明提供的一种支持简易阻错的通道共享环保护的实现方法， 通道共享 环保护在保护粒度上直接对应到业务，在业务的上路节点和下路节点直接进行 双端倒换形成新的环路，不再同复用段环保护一样采用故障跨段两端相邻节点 进行双端倒换的方式，避免了形成一个较长的重叠的迂回环路，通道共享环保 护的实现更加灵活和节约； 同时在此基础上，对于网络双跨段和多跨段故障情 况下的业务阻错处理，可以通过将已倒换节点调整为空闲状态的方式，在网络 保护能力不变的基础上， 实现无需关断业务发送设备而简易阻错的功能。 附图简要说明
图 1为环网中 D-E跨段发生故障时的两纤复用段共享环保护和两纤通道共 享环保护的保护原理对照示意图；
图 2为现有技术中， C- D和 E- F两个跨段同时存在故障情形下环网共享保 护倒换引发的业务错连情形示意图；
图 3为两纤通道共享环保护传输系统示意图；
图 4为节点 APS处理流程图；
图 5a为上路业务操作示意图；
图 5b为下路业务操作示意图；
图 5c为上下路业务操作示意图；
图 5d为直通业务操作示意图；
图 6为节点状态为 PASS的通道保护处理流程图；
图 7a-7g分别为通道共享环不同保护情形的示意图；
. 图 8为节点状态为 SWITCH的通道保护处理流程图； · . . . . ,:: 图 9为环网中 C-D跨段存在故障时的两纤通道共享环保护示意图。 ' 图 10为环网中 C-D跨段和 E-F跨段存在故障时的两纤通道共享环保护示 意图；
图 11为环网中 C-D跨段、 E-F跨段、 H-A跨段存在故障时的两纤通道共享 环保护示意图。 . 实现本发明的最佳方式
本发明是一种采用波分复用 WDM (Wave Division Multiplexing)技术的 环形光传输网中通道共享环保护的保护倒换和阻错 （squelching/prevent misconnections) 的实现技术。
本发明提出一种光网络中支持简易阻错的通道共享环保护的实现方法， 主 要包括两方面内容：首先，提出了一种根据通道业务的上下路节点执行倒换的 保护倒换实现方法；其次，本发明通过采用新的通道共享环保护的保护倒换实 现方法，对业务可能错连的情形下的倒换操作进行适当调整，可以在不影响保 护功能的前提下，不必通过关断业务发送端设备而实现业务阻错处理，可以有 效消除阻错引发业务发送设备开关操作带来的潜在风险。本发明采用的支持简 易阻错的通道共享环保护方法的过程为：
首先， 将支持通道共享环保护倒换的 APS软件下载到环形光网络所属每个 节点的 APS控制单板内。该软件的设计中，在 ITU- T协议中规定空闲态 (IDLE)、 直通态 (PASS)、倒换态 (SWITCH)三种节点状态的基础上，再引入三种通道保护 状态： 通道倒换态 (CSWITCH)、通道直通态（CPASS)和通道空闲态（CIDLE)。其 中通道倒换态对应将本地需要保护的业务信号在工作倒换和保护通道间的切 换操作；通道直通态对应将本地保护通道连通的操作；通道空闲态对应本地业 务信号由工作通道正常上、下的操作。通道保护状态是在节点状态的基础上结 合本地业务配置、 网络拓扑信息进一步得出的。
其次， 通过网管进行通道共享环保护类型的保护组配置。 将保护组信息作 为保护配置信息下载并存储到 APS控制单板的数据库中。所述保护组的含义是 指网络中某一设定保护配置的自身属性（ITU- T标准中定义的返回方式、等待 恢复（WTR)时间.、 阻错使能状态、信号劣化保护等)、涉及监测器和执行器的 物理地址信息、 网络拓扑结构信息、本节点相关的被保护业务配置信息 (包括 业务配置类型 (Operation)、 上路节点 （AddNode)、 下路节点（DropNode) )等 的逻辑集合。
然后， 正常情况下环网中每个节点的状态都是空闲态。 当某一跨段 M发生 故障（对于业务接收端设备检测到的信号故障情形，可以归结为业务工作路径 上与业务下路节点相邻跨段故障）时， 依照 APS协议的处理原理， APS信令通 过在环节点之间相互应答直至稳定后，节点获得新的状态值：故障跨段相邻两 侧节点为倒换态，其它环网节点为直通态。对于图 .2中跨段 3发生故障的情形， 跨段 3两端相邻的节点 ( D的节点状态为倒换态，其它节点的节点状态为直通 态。
APS协议的实现过程主要是通过 APS信令的应答过程来实现的， APS信令 的通讯方式可以包括多种 （如字节流方式和 IP包方式等）， 下面以 TU-T标准 中定义的 K1/K2字节方式为例进行说明。一个 APS信令应答过程达到一个稳态 后，每个节点收到的 K字节就不再变化，这时收到的 K字节一定是距当前节点 最近的故障跨段相邻节点发出的， 根据表 1、 表 2所示的 ITU- T标准对 K字节 的定义 ( IP包信令的格式可以较 K字节更加灵活，但应包括 K字节中的信息）， K字节来源节点的标识可以在 κ字节中提取得到， 这样就可以根据 K字节得到 故障跨段在环网中的位置。例如前面图 1所示，跨段 4发生故障触发 APS协议， 当 APS协议达到稳态后， 节点 A收到的逆时针环方向 K字节的源节点是 E， 收 到的外环方向 K字节的源节点是 D。
表 1 K1字节结构定义：
APS请求命令码（1一 4位） 目的地址 ID (5— 8位) 2字节结构定义: 源地址 ID ( 1— 4位）
Figure imgf000009_0001
(6位) APS状态（6— 8位） 其次， 进一步根据节点状态和环网业务配置信息（业务上下路节点、 环网 拓扑结构等）， 判断被保护业务是否会受到故障的影响， 从而进一步确定出通 道保护状态： 受到故障影响业务的上、下路节点的保护状态为通道倒换态， 受.. 影响业务保护路径上的节点为通道直通态，其它节点为通道空闲态，并据此状 ^ 态值确定相应的保护倒换动作。 对于图 9中跨段 3发生故障的情形， 业务. 受到故障影响， 则业务 T1的上、下路节点 C， E的通道保护保护状态变化为通': 道倒换态， 业务 T1保护路径上的节点（B， A, H， G， F)的通道保护状态为通道直 通态， 业务 T1工作路径上的中间节点 D的通道保护状态为通道空闲态。 对于 网络中单跨段故障情形， 不存在业务错连的可能， 也就不需要阻错处理。
然后， 在跨段 M故障发生后， 如果又有另一跨段 N发生故障， 如果跨段 N 同跨段 M所影响的业务完全相同，那么网络 APS状态不会发生新的变化，也不 需要执行新的倒换操作；如果跨段 N的故障使得新的业务受到影响，假定继续 进行类似跨段 M故障时的倒换操作，这样就满足了环网业务可能发生错连的条 件而需要阻错处理。对于这种需要阻错处理的网络双跨段故障情形，实际上对 于先后受到故障影响的业务来说， 正常工作路径和保护路径都分别存在故障， 实际上倒换已经没有意义，而且还会引发业务错连，所以本发明通过网络节点 之间的 APS协议处理过程， 对于已经执行倒换的业务上、下路节点， 结合本地 业务配置和网络拓扑结构信息，识别出当前业务正常工作路径和保护路径同时 存在故障的情形， 立即将原有业务上、下路节点的倒换态更新为空闲态， 这样 可能发生错连的业务会重新倒换回到最初的正常工作路径，这样就消除了业务 错连现象，也不会影响网络的保护功能。并据此状态值确定相应的保护倒换动 作。
对于某一节点同时存在上路和下路业务的情形， 最终的通道保护状态应根 据受影响业务的判断得出，如果上路业务和下路业务同时受到影响，该节点的 通道保护状态显然应为通道空闲态。
最后，对于网络中多跨段故障的复杂情形。在跨段 M和跨段 N发生故障后， 又有跨段 Q发生故障的处理类似上面得到步骤。通过分别针对判断网络中被跨 段 M, N， Q故障影响的所有业务进行如下判断：如果业务的工作路径和保护路径 均存在故障， 则该业务对应的上、 下路节点的通道保护状态应为通道空闲态； 如果只是工作路径存在故障，受到故障影响业务的上、下路节点的保护状态为 通道倒换态，受影响业务保护路径上的节点为通道直通态，其它节点为通道空 闲态； 如果只是保护路径存在故障， 那么节点通道状态应维持原有状态。并据 此状态值确定相应的保护倒换动作。
• 同双跨段情况， 对于某一节点同时存在上路和下路业务的情形， 最终.的通 道保护状态应根据受影响业务的判断得出，如果上路业务和下路业务同肘受到 影响， 该节点的通道保护状态显然应为通道空闲态。 ·
下面结合附图， 对本发明的具体技术实施方案作详细的描述。 所有的附图 加起来便于理解整个技术的内容， 包括能说明本发明技术或现有技术的图。
本发明是一种环形光网络中支持简易阻错的通道共享环保护的实现方法， 其重要特点在于；通道共享环保护在保护粒度上直接对应到业务，在业务的上 路节点和下路节点直接进行双端倒换形成新的环路，不再同复用段环保护一样 采用故障跨段两端相邻节点进行双端倒换的方式，避免了形成一个较长的重叠 的迂回环路，通道共享环保护的实现更加灵活和节约； 同时在此基础上，对于 网络双跨段和多跨段故障情况下的业务阻错处理，可以通过将已倒换节点调整 为空闲状态的方式，在网络保护能力不变的基础上，实现无需关断业务发送设 备而简易阻错的功能。
图 3描述了一个简单的光传输网的网络结构示例， 每两个网络节点间有两 根或两根以上的光纤连接，每根光线包括多个通道，每个通道可以承载一路业 务信号； 节点对应机站。在两根光纤的情况下， 光信号传输方向正好相反。对 于图 3示例的光网络， 可以支持一个两纤单向 /双向复用段共享环保护， 也可 以同时支持多个两纤单向 /双向通道共享环保护类型的保护配置。 为了便于描 述， 图中仅标出的沿着逆时针环方向的业务示例， 对于双向保护配置来说， 外 环也可以完全对等进行业务配置， 但是保护倒换原理基本一致。
图 4描述了本发明的 APS处理的基本流程。 图中包括如下步骤： .
步骤 401， 系统启动， 网管配置 APS数据信息；
步骤 402， 某一节点 APS控制器收到网管命令 /检测板检测到故障 /收到新 的 APS信令；
步骤 403， 生成并输出 APS信令， 分别向环的两端发送， 直到系统 APS信 令应答稳定， 得出新的节点状态；
步骤 404， 根据节点状态和保护业务信息， 根据业务保护和阻错需要， 确 定通道保护状态， 进而确定保护倒换动作；
步骤 405， 发送保护倒换动作命令至 APS执行单板，返回步骤 402。
由以上流程可知， APS处理是： 首先将 APS软件下载到 APS控制板， 上电 启动后先通过网管下发 APS配置数据信息。当某一跨段发生故障时，这一跨段: 的下游相邻节点的. APS检测单板就会检测到该故障，故障信息发到 APS控制单 板后即可启动一个新的 APS过程； APS控制单板收到人工下发的网管命令也可 启动一个新的 APS过程；节点收到新的 APS信令标志着当前已由环中的其它节 点发起了一个新的 APS过程， 同时作为本节点 APS过程的开始。 当节点 APS 过程开启后， APS控制单板根据协议进行处理， 生成新的 APS信令， 随后分 别通过环的长径和短径发向对端节点， 这样整个环中的节点进行反复地 APS 信令应答直至稳定下来。节点在处理每一次 APS信令变化后，都会首先确定新 的节点状态，然后再根据节点状态和保护业务的信息做进一步的处理，确定出 通道保护状态， 而后才能确定倒换动作并发送到 APS执行单板。至此， 一个完 整的 APS过程就完成了， 系统返回开始等待下次 APS过程。
下面的内容就对本发明的核心步骤——通道共享环保护倒换及阻错的实 现过程举例加以描述。
5. 1单跨段故障的实现过程举例
由于对于一个跨段来说， 一条业务占用一个通道， 所以通道共享环保护实 际上就是可以直接对应到业务的保护，本发明有效处理通道共享环的 APS的主 要手段就是借助于保护业务的信息和网络拓扑结构信息，业务信息主要包括配 置类型（operation)、 上路节点 （AddNode)、 下路节点（DropNode)。 对于一个 节点来说，保护业务的不同设置导致了节点的不同配置类型， 为了使节点的业 务配置类型得以统一规定， 应确定环的某一方向 （顺时针方向或逆时针方向） 作为基准方向，一般以逆时针方向作为基准方向，后面要用到的两个节点相对 当前节点的远近比较也是以逆时针环方向为基准的。这里所说的上路节点指的 是在当前节点下路业务的上路节点；下路节点指的是在当前节点上路业务的下 路节点。 下面结合图 5a、 5b、 5c 、 5d对保护业务配置类型的定义做一说明。
如图 5a所示， 在 B节点的逆时针环方向工作通道没有下路业务， 而该工 作通道在本节点存在一条上路业务， 则 B节点的配置类型定义为 "上路"或
"Add"; 下路节点为 (：， 上路节点为 B。如图 5b所示， 逆时针方向工作通道上 一业务自 A节点上路、 B节点下路， 中间可以存在中间节点， 而 B节点在该工 作通道没有上路业务， 则 B节点的配置类型定义为 "下路 "或 "Drop"; 上路 节点为 A，下路节点为 B。 如图 5c所示， B节点的逆时针方向工作通道既有一 条下路业务， 又有一条上路业务， 则 B节点的配置类型定义为 上下路 "或'
"AddDrop"; 上路节点为 A, 下路节点为 C。如图 5d所示， 节点 B .的工作通邋 不存在本地的上下路业务，只有一条直通的业务，即节点 A上路、节点 C下路， 则 B节点的配置类型为 "直通"或" Pass"; 上路节点为 A， 下路节点为 C。还 有一种情况， 就是 B节点工作通道无业务， 则 B节点的配置类型为 "空"或
"Null ", 由于这种情形不会涉及任何业务， 所以不影响倒换处理。 通过上面 的叙述可以看出，这里所说的业务信息并不是具体针对一条业务而言的，而是 针对环的工作通道而言的业务的综合信息。
在环的 APS信令应答稳定后， 环上各个节点的节点状态也就确定下来： 发 生故障的情形， 故障跨段相邻的节点的状态为 SWITCH (倒换方向为故障跨段 相邻侧方向）， 与故障跨段不相邻的节点的状态均为 PASS, 但节点孤立即节点 两侧跨段同时故障时， 该节点状态为 IDLE; 故障修复后系统回复时的节点状 态均为 IDLE。这时通过当前节点的节点状态、工作通道业务信息、 APS信令源 节点信息、再加上环网的节点顺序信息，就能够最终确定该节点的通道保护状 态，下面通过示例来对该过程做进一步表述，其中，节点状态划分为三种情况。 (一）节点状态为 PASS的处理过程
如图 6所示， 描述了节点状态为 PASS时的处理流程。
对于本节点业务配置类型为 Add的情形， 结合图 7a和图 7b， 以节点 C当 前节点。
( 11 )如图 7a， 业务自当前节点 C上路， 节点 F下路； 节点 C收到的来自 外环方向的 APS信令的源节点为节点 D。通过沿逆时针环方向比较节点 F远于 节点 D， 这意味着工作业务经过故障跨段， 已经受到故障影响， 需要保护， 所 以通道保护状态设置为通道倒换态 (CSWITCH)； 由于故障跨段位于当前节点右 侧 （沿业务方向）， 右侧通道开关倒换。
( 12)如图 7b， 业务自当前节点 C上路， 节点 D下路； 节点 C收到的来自 外环方向的 APS信令的源节点为节点 D。通过沿逆时针环方向比较下路节点不 远于故障跨段相邻节点，这意味着工作业务不经过故障跨段，没有受到故障影 响， 不需要保护， 所以通道保护状态设置为通道直通态 (CPASS) ; 不需要开关 倒换。
对于本节点业务配置类型为 Drop的情形， 结合图 7a和图 7c， 以节点 F当 前节点。 .
( 13)如图 7a， 业务自节点 C上路， 当前节点 F下路； 节点 F收到的来自 逆时针环方向的 APS信令的源节点为节点 E。 通过比较沿逆时针环方向节点 C 近于节点 E，这意味着工作业务经过故障跨段， 已经受到故障影响，需要保护， 所以通道保护状态设置为通道倒换态 (CSWITCH)； 由于故障跨段位于当前节点 左侧 （沿业务方向）， 左侧通道开关倒换。
( 14)如图 7c， 业务自节点 E上路， 当前节点 F下路； 节点 F收到的来自 逆时针环方向的 APS信令的源节点为节点 E。通过比较沿逆时针环方向节点上 路节点不近于故障跨段相邻节点，这意味着工作业务不经过故障跨段没有受到 故障影响， 不需要保护， 所以通道保护状态设置为通道直通态 (CPASS) ; 不需 要开关倒换。
对于本节点业务配置类型为 AddDrop的情形， 相应的处理过程可以分解为 业务配置类型分别为 Add和 Drop的两个子过程， 先后按照上面的方法处理完 两个子过程后，将两次的结果进行归并，就可以得到通道保护状态及开关动作。
对于本节点业务配置类型为 Pass或 Null的情形， 由于本发明对通道共享 环共享保护只在业务上下路节点进行倒换， 可以直接得出通道保护状态为
CPASS, 执行保护通道穿通操作。
(二）节点状态为 SWITCH的处理过程
如图 8所示， 描述了节点状态为 SWITCH时的处理流程。
下面分别结合图 7a、 7b、 7c、 7d、 7e、 7f、 7g对节点状态为 SWITCH时的 八种处理分支做进一步描述。
(21 )如图 7c， 故障跨段 4的右侧相邻节点 E的节点状态应为 SWITCH, 节点倒换方向为左侧。 E节点的业务配置类型为 Add, 由于没有业务经过故障 跨段而受到影响， 所以通道保护状态应为 CIDLE, 无开关动作。
(22)如图 7d， 故障跨段 4的右侧相邻节点 E的节点状态应为 SWITCH, 节点倒换方向为左侧。 E节点的业务配置类型为 Drop, 由于此时业务必然会经 过故障跨段而受到影响， 所以通道保护状态应为 CSWITCH, 由于故障跨段位于 当前节点左侧 （沿业务方向）， 左侧通道开关倒换。
(23)如图 7e， 对节点 E的配置类型为 AddDrop的情形， 结合上面（21 )、 (22)的分析， 本节点的上路业务不会受到故障的影响， 而在本节点下路的业 务必然会受到故障的影响， 所以处理结论与 （22)相同： 通道保护状态应为 Ϊ CSWITCH,由于故障跨段位于当前节点左侧（沿业务方向），左侧通道开关倒换;：;
(24)如图 7a， 故障跨段 4的右侧相邻节点 E的节点状态应为 SWITCH, ' 节点倒换方向为左侧。 E节点的业务配置类型为 Pass, 由于本发明对通道共享 环共享保护只在业务上下路节点进行倒换， 所以通道保护状态为 CIDLE, 不需 要通道开关倒换。同样由于业务倒换后也不通过 D节点的保护通道，不需要保 护通道直通。 故 D节点也不需要通道开关倒换。
(25)如图 7f， 故障跨段 4的左侧相邻节点 D的节点状态应为 SWITCH, 节点倒换方向为右侧。 D节点的业务配置类型为 Add, 由于该业务无论自何节 点下路，都必然会经过故障跨段而受到影响，所以通道保护状态应为 CSWITCH, 由于故障跨段位于当前节点右侧 （沿业务方向）， 右侧通道开关倒换。
(26)如图 7b, 故障跨段 4的左侧相邻节点 D的节点状态应为 SWITCH, 节点倒换方向为右侧。 D节点的业务配置类型为 Drop, 由于没有业务经过故障 跨段而受到影响， 所以通道保护状态应为 CIDLE, 无开关动作。
(27)如图 7g， 对节点 D的配置类型为 AddDrop的情形， 结合上面（25)、 (26 )的分析， 本节点的下路业务不会受到故障的影响， 而在本节点上路的业 务必然会受到故障的影响， 所以处理结论与 （25) 相同： 通道保护状态应为 CSWITCH,由于故障跨段位于当前节点右侧（沿业务方向），右侧通道开关倒换。
(28)如图 7a， 故障跨段 4的左侧相邻节点 D的节点状态应为 SWITCH, 节点倒换方向为右侧。 D节点的业务配置类型为 Pass, 由于本发明对通道共享 环共享保护只在业务上下路节点进行倒换， 且故障跨段相邻节点也不需要穿 通， 所以通道保护状态为 CIDLE, 不需要通道开关倒换。 同样由于业务倒换后 也不通过 E节点的保护通道， E节点也不需要 PASS。
(29) 如图 7b， 故障跨段 4的右侧相邻节点 E的节点状态应为 SWITCH, 节点倒换方向为左侧。 E节点的业务配置类型为 Null, 由于本发明对通道共享 环共享保护只在业务上下路节点进行倒换， 且故障跨段相邻节点也不需要穿 通， 所以通道保护状态为 CIDLE, 不需要通道开关倒换。
(三）节点状态为 IDLE的处理过程
对于节点状态为 PASS或 SWITCH的处理过程， 是针对网络检测到故障后的 保护过程。故障修复后的业务由保护通路向工作通路的回复作为 APS的必要内 容， 网络检测到故障消失， 随即整个 APS .系统通过信令应答， 稳定后的节点状: 态就会由原来的 PASS或 SWITCH回到 IDLE态。对节点状态回到 IDLE的通道保. 护状态的确定相对简单， 不需要经过特别的判断： 通道保护状态为 CIDLE， 通 道开关状态均为无倒换状态。
在确定了通道保护状态以及通道开关倒换状态后， 通道共享保护的倒换动 作也就可以确定了， APS控制板就将倒换命令发送给 APS执行板执行相应的 APS 倒换操作。
5. 2双跨段故障的实现过程举例
在描述双跨段故障情形的举例说明之前， 首先做单跨段故障情形举例。 图 9为环网中 C-D跨段存在故障时的两纤通道共享环保护的保护原理示意图。 C-D 跨段发生故障后， 故障相邻节点 C、 D分别检测到故障发生， 并且分别向各自 对端节点发起 APS信令，在依照 ITU-T标准规定的 APS协议应答过程中， 网络 的各个节点分别解析各自收到的信令内容，结合本地存储的网络拓扑信息得到 故障发生的单个跨段（跨段 3)， 继而再结合本地业务配置信息判断出本地上 / 下路的业务是否经由故障跨段， 如果本地上 /下路的业务受故障影响则执行相 应的倒换操作； 反之则保持直通状态； 对于本地没有配置业务上 /下的节点则 无需做任何操作， 保持在空闲态。 图 9中业务 T1的上下路节点 C和节点 E分 别由原有的空闲状态变为倒换状态（C节点为右侧倒换， E节点为左侧倒换）， 将业务 T1由正常通过信道倒换到保护信道。 对于业务 T2由于不受故障影响， 所以不作相应的倒换操作。单跨段故障情形下的保护倒换过程参加 5. 1节的描 述。
图 10为环网中 C-D跨段发生之后， E - F跨段又发生故障时的两纤通道共享 环保护的保护原理示意图。在图 10中，跨段 3故障影响业务 T1完成保护倒换 后， 跨段 5又发生故障， 如果按照跨段 3的处理方式使新的受影响业务 T2发 生类同业务 T1的双端倒换， 这样就会导致环网业务发生错连现象。 对此本发 明提出的做法是：
( 1 ) 首先各个节点根据接收的 APS信令判断出网络故障的发生情况 （具 体判定过程参见 5. 1节的描述)， 最后每个节点都能够根据接收的 APS信令判 断出故障发生在 C- D跨段 3和 E-F跨段 5。
(2 )对于已经发生倒换的节点 C和节点 E， 根据双跨段故障的分布， 再结 合网络拓扑结构、.业务 T1的上下路信息， 可以做出判断： 业务 T1的工作路径
(C-D- E)和保护路径 (C-B-A-H- G-F- E) .均存在故障， 所以根据本发朋简易驵' 错的原理，应该立即将节点 C， E原有的通道倒换状态变化为通道空闲状态，完 成简易阻错的通道保护倒换。 对于跨段 5故障所影响业务. T2的上下路节点 E，F，结合网络拓朴结构、业务 T1的上下路信息， 也可以做出类似判断： 业务 T2的工作路径（E-F)和保护路径（E-D- C- B-A-H- G- F)均存在故障， 所以根 据本发明简易阻错的原理，应该立即将节点 E原有的通道倒换状态变化为通道 空闲状态，将节点 F原有的通道直通状态变化为通道空闲状态， 而不会因 E - F 跨段故障进行倒换， 达到简易阻错的目的。 对于其它存在本地业务（业务 T3、 Τ4)上 /下路的节点 G、 H、 B， 均可以判断出两个故障均位于本节点的上 /下路 业务的保护路径上，所以通道保护状态维持原来的状态，不需要新的保护倒换 动作。对于不存在本地上 /下路业务得到节点 A, D,则通道保护状态始终保持在 通道空闲状态。
5. 3多跨段故障的实现过程举例
图 11为环网中发生图 10所示的双跨段故障的基础上， A-H跨段 8又发生 故障的情形。 按照本发明提出的方法， 实现的过程为：
( 1 )首先各个节点根据接收的 APS信令判断出网络故障的发生情况 （具 体判定过程参见 5. 1节的描述）， 最后每个节点能够分析得到的网络故障发生 情况如下： 对于节点 D，E， 能够判断出跨段 3和跨段 5存在故障； 对于节点 F，G，H， 能够判断出跨段 5和跨段 8发生故障； 对于节点 8，(， 能够判断出 跨段 3和跨段 8发生故障。
( 2 )对于节点 C和节点 E,根据双跨段故障的分布，再结合网络拓扑结构、 业务 T1的上下路信息， 可以做出判断： 业务 T1的工作路径 （C-D-E) 和保护 路径（C- B- A-H- G-F-E)均存在故障， 所以根据本发明简易阻错的原理， 应该 继续保持节点 C, E原有的通道空闲状态，完成简易阻错的通道保护倒换。对于 节点 E，F， 结合网络拓扑结构、 业务 T1的上下路信息， 也可以做出类似判断: 业务 T2的工作路径（E-F)和保护路径 （E- D- C- B-A- H-G-F)均存在故障， 应 该继续保持节点 E, F原有的通道空闲状态，完成简易阻错的通道保护倒换。对 于节点 B、 H， 结合网络拓扑结构、 业务 T3的上下路信息， 也可以做出判断： 业务 T4的工作路径（H-A-B)和保护路径（H- G- F E- D-OB)均存在故障， 应 该将 B， H原有的通道直通态变更为通道空闲状态，完成简易阻错的通道保护倒 换。 对于节点0、 H, 结合网络拓扑结构、 业务 T3的上下路信息， 也可以做出 判断： 业务 T3的工作路径（G-H)和保护路径（G- F- E- D-C-B-A- H)， 仅保护路 径存在故障，则节点 G，H.的通道保护状态不受影响（节点 G维持原有的通道直 通状态； 节点 H由于同时存在业务 T3和 T4， 应根据受故障影响的业务 Τ4的 判断确定通道保护状态为通道空闲状态）。对于不存在本地上 /下路业务得到节 点 A, D,则通道保护状态始终保持在通道空闲状态。
当然， 本发明还可有其他多种实施例， 在不背离本发明精神及其实质的情 况下，熟悉本领域的技术人员当可根据本发明作出各种相应的改变和变形，但 这些相应的改变和变形都应属于本发明所附的权利要求的保护范围。 工业应用性
本发明所述方法， 通道共享环保护在保护粒度上直接对应到业务， 在业务 的上路节点和下路节点直接进行双端倒换形成新的环路，不再同复用段环保护 一样采用故障跨段两端相邻节点进行双端倒换的方式，避免了形成一个较长的 重叠的迂回环路， 通道共享环保护的实现更加灵活和节约； 同时在此基础上， 对于网络双跨段和多跨段故障情况下的业务阻错处理，可以通过将已倒换节点 调整为空闲状态的方式，在网络保护能力不变的基础上，实现无需关断业务发 送设备而简易阻错的功能。本发明方法适合于采用波分复用技术的环形光传输 网中，用于通道共享环保护的保护倒换和阻错，本发明方法同样适合于其它光 纤传输网络中， 以及存在类似应用的其他各领域。

Claims

权利要求书
1、 一种支持简易阻错的通道共享环保护的实现方法， 其特征在于， 在环 形网中，对于工作路径出现故障跨段的业务，直接在该业务工作路径的上路节 点和下路节点进行双端倒换， 形成避开所述故障跨段的保护路径。
2、 根据权利要求 1所述的方法， 其特征在于， 对于所述环形网中工作路 径和保护路径均存在故障跨段的业务，将该业务的上、下路节点的通道保护状 态转为通道空闲态，从而取消先前可能发生的倒换操作，在不关断业务发送设 备的条件下避免引发业务错连的情形， 实现简易阻错。
3、 根据权利要求 2所述的方法， 其特征在于， 进一步包括如下步骤： 步骤一， 将支持通道共享环保护倒换的自动保护倒换模块下载到所述环形 网中每个节点的自动保护倒换控制单板内； 在所述倒换模块中对应 ITU-T G. 841协议中规定的空闲态、 直通态和倒换态三种节点状态引入通道倒换态、 通道直通态和通道空闲态三种通道保护状态：所述通道倒换态对应将本地需要 保护的业务信号在工作倒换和保护通道间的切换操作，所述通道直通态对应将 本地保护通道连通的操作，所述通道空闲态对应本地业务信号由工作通道正常 上、 下的操作；
步骤二， 通过网管将保护组信息作为保护配置信息下载并存储到所述控制 单板的本地数据库中。
步骤三， 在没有故障跨段条件下， 每个节点的节点状态都是空闲态， 在出 现故障跨段后，依照 APS协议的处理原理， 自动保护倒换信令通过在环节点之 间相互应答直至稳定后，所述故障跨段相邻两侧节点的节点状态为倒换态，且 倒换方向为故障跨段相邻侧方向， 其它节点的节点状态为直通态。
步骤四， 根据节点状态和接受的 APS信令， 并结合所述保护组信息， 判断 被保护业务是否会受到故障跨段的影响，从而进一步确定出各节点的通道保护 状态： 受故障影响的业务的上、下路节点的通道保护状态为通道倒换态，执行 工作路径相邻侧的倒换操作；受故障影响的业务的保护路径上的节点的通道保 护状态为通道直通态，需要执行保护通道穿通操作；故障跨段相邻节点的通道 保护状态为通道空闲态；其余节点的通道保护状态为通道直通态，需执行保护 通道穿通操作； 步骤五， 在前面单跨段故障的基础上， 对于每增加的一个故障跨段， 都需 要重新按照 APS协议得出每个节点协议应答稳定后的节点保护状态；
步骤六， 在得出多跨段故障情形下的节点状态后， 再根据节点状态和所述 保护组信息， 对网络的每一个节点的上、下路业务均需做如下处理： 对于工作 路径和保护路径同时存在故障的业务，则在该业务上、下路节点的通道倒换状 态应该为通道空闲态，撤销先前可能已经发生的倒换操作；对于仅仅工作路径 存在故障的业务，则在该业务上、下路节点的通道倒换状态应该为通道倒换态， 执行工作路径相邻侧的倒换操作， 该业务保护路径上的节点处于通道直通态； 对于仅仅保护路径存在故障即工作路径没有故障的业务，则该业务在其上、下 路节点的通道倒换状态应该保持原有的状态， 不需执行新的倒换操作。
4、 根据权利要求 3所述的方法， 其特征在于， 在所述步骤四中， 所述确 定出各节点的业务是否受到故障影响包括：对于处于直通态的节点，根据业务 配置类型，并通过判断在本节点上路的业务的下路节点沿逆时针环方向是否远 于来自顺时针环方向信令的源节点，以及在本节点下路的业务的上路节点沿逆 时针环方向是否近于来自逆时针环方向信令的源节点的方式，来确定该节点的 业务是否受到故障影响。
5、 根据权利要求 3所述的方法， 其特征在于， 在所述步骤四中， 所述确 定出各节点的业务是否受到故障影响包括：对于处于倒换态的节点，根据节点 的倒换方向和业务配置类型来确定该节点的通道保护状态。
6、 根据权利要求 3所述的方法， 其特征在于， 故障跨段被修复后， 节点 状态由直通态或倒换态转变为空闲态，节点的通道保护状态也转变为通道空闲 态。
7、 根据权利要求 3、 4、 5或 6所述的方法， 其特征在于， 所述步骤二中， 所述保护组信息包括： 网络中设定保护配置的自身属性、涉及监测器和执行器 的物理地址信息、 网络拓扑结构信息和本节点相关的被保护业务配置信息。
8、 根据权利要求 7所述的方法， 其特征在于， 所述自身属性包括： ITU-T 标准中定义的返回方式、等待恢复时间、阻错使能状态和信号劣化保护； 所述 本节点相关的被保护业务配置信息包括:业务配置类型、上路节点和下路节点。
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WO2005015795A1 (en) * 2003-08-05 2005-02-17 Telecom Italia S.P.A. Method for providing extra-traffic paths with connection protection in a communication network, related network and computer program product therefor

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WO2015052226A1 (en) 2013-10-11 2015-04-16 F. Hoffmann-La Roche Ag Thiazolopyrimidinones as modulators of nmda receptor activity
EP3415519A1 (en) 2013-10-11 2018-12-19 F. Hoffmann-La Roche AG Thiazolopyrimidinones as modulators of nmda receptor activity
US11362861B2 (en) * 2020-01-28 2022-06-14 Honda Motor Co., Ltd. Operating device

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