WO2012174963A1

WO2012174963A1 - Method and device for selecting ptp lsp

Info

Publication number: WO2012174963A1
Application number: PCT/CN2012/075664
Authority: WO
Inventors: 张君辉; 何力
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-23
Filing date: 2012-05-17
Publication date: 2012-12-27
Also published as: CN102843726A

Abstract

The present invention provides a method and a device for selecting a PTP LSP. In the method, the 1588 capability and the bandwidth reservation capability of each node are circulated, and a PTP LSP is selected according to a circulation result. The selected PTP LSP has the fewest nodes that do not support the 1588 capability or the bandwidth reservation capability. By means of the technical solution provided by the present invention, the clock recovery quality and the applicability and reliability of the synchronization service are further improved.

Description

TECHNICAL FIELD The present invention relates to the field of communications, and in particular, to a method for selecting a Precision Switching Protocol (PTP) Label Switched Path (LSP) Device. BACKGROUND With the rapid development of 3G networks, the 1588 time synchronization protocol has received more and more attention and wide application in communication networks. Domestic and foreign operators continue to use the 1588 protocol for time synchronization and gradually replace the use of GPS for time synchronization. In the IEEE 1588v2 standard, multicast and unicast transmission methods for precise timing protocol (PTP) packets are specified. With the gradual application of the 1588 network, it is necessary to traverse the third-party network to implement frequency synchronization and phase synchronization. However, because the intermediate network device may not support PTP, there is a delay change when the PTP packet passes through the third-party network, that is, the packet delay changes (PDV). If the PDV is too large, it will affect the clock recovery performance of the slave device. In addition, for the Circuit Emulation Service (CES) adaptive clock recovery, if the PDV generated by the intermediate network exceeds a certain range, it will be serious. Affects the performance of Adaptive Clock Recovery (ACR). Therefore, if the intermediate network device can establish an optimized PTP path, the clock synchronization device at both ends of the network analyzes the PDV introduced by the network device, selects an optimized PTP path, and can switch to the standby PTP path when the PDV is degraded. It will greatly improve the quality of clock recovery and the reliability of synchronous services. With the extensive deployment of the Multi-Protocol Label Switching (MPLS) network, it is inevitable to implement frequency synchronization and phase synchronization through a third-party MPLS network. For details about PTP synchronization across a third-party network, see Figure 1. In the IETF standards organization, the TICTOC working group focuses on high-precision frequency and time synchronization in pure IP networks and MPLS networks. The draft-ietf-tictoc-1588overmpls draft describes the application scenarios and implementation techniques of 1588 over MPLS, which proposes extensions. Open Shortest-Path First (OSPF), the protocol performs 1588 capability advertisement, and establishes a PTP-dedicated LSP to implement synchronous service transmission. However, for a non-1588 device, if the bandwidth reservation capability is not supported, the PTP traffic may be congested, resulting in degradation of PDV performance at both ends of the network. Due to the complexity and uncertainty of third-party network traffic, previously established PTP LSPs may be congested, affecting clock recovery. Therefore, some mechanism is needed to select or switch to the new PTP LSP to prevent the PDV performance of the critical clock synchronization service from degrading or being unavailable. RFC4872 extends the RSVP-TE protocol, allowing for setup The MPLS TE LSP is connected to the lj end and performs protection switching. In addition, during the network maintenance process, the corresponding node may need to be added or deleted, and the network topology changes. At this time, there may be a new and more optimized PTP path. The head node LSR triggers reevaluation and finds a better LSP. RFC4736 Description A re-optimization mechanism is used to discover and establish a better TE LSP. SUMMARY OF THE INVENTION The present invention provides a method and an apparatus for selecting a PTP LSP, so as to at least solve the problem that the previously established PTP LSP may be congested due to the complexity and uncertainty of the third-party network traffic in the related art, thereby affecting the clock recovery problem. . According to an aspect of the present invention, a method of selecting a PTP LSP is provided. The method for selecting a PTP LSP according to the present invention includes: performing a notification of the 1588 capability and the bandwidth reservation capability of each node; and selecting a PTP LSP according to the result of the notification, where the selected PTP LSP does not support the 1588 capability and the bandwidth reservation capability. The least number. The selected PTP LSP supports the 1588 service and the circuit emulation service (CES). After selecting a PTP LSP according to the result of the notification, the method further includes: enabling a congestion detection mechanism for a node that does not support the 1588 capability and the bandwidth reservation capability. For a node that does not support the 1588 capability and the bandwidth reservation capability, the congestion detection mechanism is enabled. The PTP LSP sends a path message to the head node. The path message carries the congestion detection request. The PTP LSP does not support the 1588 capability and bandwidth pre-request. After receiving the path message, the staying node starts the congestion detection mechanism. After the congestion detection mechanism is enabled, the node that does not support the 1588 capability and the bandwidth reservation capability further includes: the node that detects the congestion sends a path error message to the head node, where the path error message carries the identifier information of the node that detects the congestion. After detecting that the congestion node sends the path error message to the head node, the method further includes: triggering the head node to perform a re-optimization operation according to the predetermined policy; and the head node bypasses the node that detects the congestion, and reselects the PTP LSP. The foregoing predetermined policy includes: determining that the triggering head node performs a re-optimization operation when the end-to-end PDV performance degradation degree and/or the packet loss rate is greater than the first threshold. The triggering head node performs the re-optimization operation, including one of the following: The tail node of the PTP LSP determines that the PDV performance degradation degree and/or the packet loss rate is greater than the first threshold by detecting, and sends a notification message to the head node, where the notification message carries the indication Error code for PDV performance degradation and/or packet loss errors. After the PTP LSP is selected and established according to the result of the notification, the method further includes: analyzing the PDV performance on the slave device or the master device, and completing the protection switching of the PTP LSP or the master clock according to the PDV performance degradation degree. For a scenario where multiple slave devices are synchronized to a single master device, the protection switch of the master device is completed according to the PDV performance degradation degree. The PTP LSP active and standby paths are set up for the 1+1 protection. The PDV of the PTP LSP active and standby paths is analyzed on the slave device. If the current PTP LSP has a PDV performance degradation greater than the second threshold, the slave device switches to another path in the PTP LSP active/standby path. The PTP LSP performs re-optimization operations to establish a new PTP LSP and PDV jitter description. For a scenario where a single slave device is synchronized to multiple master devices, the protection switch of the master device is completed according to the PDV performance degradation degree. The following: A PTP LSP is established between the slave device and each master device. If the PDV performance is analyzed on the slave device, The PDV jitter description of the PTP LSP established by the slave device is selected to be synchronized by the PTP LSP with the best PDV performance. If the PDV performance of the current PTP LSP is greater than the third threshold, The master device sends a degradation notification message to the single slave device and performs a re-optimization operation on the current PTP path. After receiving the degradation notification message, the single slave device determines whether to switch to other master devices in the multiple master devices. Before performing the notification of the 1588 capability and the bandwidth reservation capability of each node, the method further includes: an extension field in the IGP routing protocol, where the extended field is used to indicate the notification of performing the bandwidth reservation capability. According to another aspect of the present invention, a device for selecting a PTP LSP is provided. The device for selecting a PTP LSP according to the present invention includes: a capability notification module configured to perform notification of 1588 capability and bandwidth reservation capability of each node; and a routing module configured to select a PTP LSP according to the notification result, wherein the selected PTP LSP The number of nodes that do not support 1588 capability and bandwidth reservation capability is the least. The foregoing apparatus further includes: a congestion detection enabling module, configured to enable a congestion detection mechanism for a node that does not support the 1588 capability and the bandwidth reservation capability. The device further includes: a PDV performance analysis module configured to analyze PDV performance on the slave device or the master device; and a protection switch module configured to complete protection switching of the PTP LSP or the master clock according to the PDV performance degradation degree. Through the present invention, the notification of the 1588 capability and the bandwidth reservation capability of each node is performed; the PTP LSP is selected according to the result of the notification, wherein the number of nodes that do not support the 1588 capability and the bandwidth reservation capability in the selected PTP LSP is the least, and the related The complexity and uncertainty of the third-party network traffic in the technology. The previously established PTP LSP may be congested, which may affect the clock recovery problem, thereby improving the clock recovery quality and the availability and reliability of the synchronous service. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are set to illustrate,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, In the drawings: FIG. 1 is a schematic diagram of implementing PTP synchronization through a third-party network; FIG. 2 is a flowchart of a method for selecting a PTP LSP according to an embodiment of the present invention; FIG. 3 is a congestion notification based on a preferred embodiment of the present invention. Schematic diagram of PTP path re-optimization; FIG. 4 is a schematic diagram of PTP path protection of a single master according to a preferred embodiment of the present invention; FIG. 5 is a schematic diagram of PTP path protection of multiple masters according to a preferred embodiment of the present invention; FIG. A block diagram of a device for selecting a PTP path according to an embodiment of the present invention; and FIG. 7 is a structural block diagram of a device for selecting a PTP path according to a preferred embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the embodiments in the present application and the features in the embodiments may be combined with each other without conflict. 2 is a flow chart of a method for selecting a PTP LSP according to an embodiment of the present invention. As shown in Figure 2, the PTP

The method for selecting the LSP mainly includes the following processes: Step S202: Perform the notification of the 1588 capability and the bandwidth reservation capability of each node. Step S204: Select a PTP LSP according to the result of the notification, where the selected PTP LSP does not support the 1588 capability and bandwidth pre- The number of nodes with the ability to stay is the least. In the related art, when the PTP traverses the third-party network, the quality of the synchronization performance largely depends on the PDV caused by the intermediate network device, and the main factor causing the PDV is the traffic congestion of the network node. RSVP-TE supports the establishment of a DS-TE tunnel, which means that the highest priority can be established and a certain bandwidth can be reserved for the tunnel. If the tunnel is only used to carry PTP services, the priority is the highest, and the reserved bandwidth is not exceeded. A node may consider that there is no congestion. However, in reality, due to the complexity and cost factors of the hardware implementation, the intermediate network device may not support the reserved bandwidth capability. In addition to notifying the 1588 capability, it is also required to notify the device whether the bandwidth reservation capability is supported. When establishing a TE tunnel, if this node does not support 1588 or does not support reserved bandwidth capability, you should bypass this node as much as possible to avoid introducing PDV. Using the method shown in Figure 1, selecting a PTP LSP based on the result of the notification can improve the clock recovery quality and the availability and reliability of the synchronization service. The selected PTP LSP can carry the CES service for frequency recovery, in addition to carrying the 1588 service for frequency or time recovery. Preferably, if there is a node in the selected PTP LSP that does not support the 1588 capability and the bandwidth reservation capability, the congestion detection mechanism may be enabled on the node that does not support the 1588 capability and the bandwidth reservation capability. The congestion detection mechanism can be enabled on the nodes that do not support the 1588 capability and bandwidth reservation capability in the following manner:

(1) The head node in the PTP LSP sends a path message, where the path message carries a congestion detection request;

(2) A node that does not support the 1588 capability and bandwidth reservation capability in the PTP LSP starts the congestion detection mechanism after receiving the path message. In the preferred implementation process, in order to ensure that the PDV of the established PTP LSP is optimal, the MPLS TE signaling needs to support the notification and routing of the 1588 capability and the bandwidth reservation capability, and supports the congestion detection request. In addition, the LSP traversal is not 1588. The device hop count is also the least; the main factors affecting the end-to-end PDV of the MPLS network are: (1) the QoS scheduling policy of the MPLS tunnel and the congestion of the node; (2) whether the 1588 capability is supported; (3) the device hopping (4) Whether to support bandwidth reservation capability; (5) Changes in network traffic.

When the CSPF is selected, the path of the 1588 capability is preferred, and the node that supports the bandwidth reservation capability is selected. If the network node does not support the 1588 capability or the bandwidth reservation capability, the congestion detection mechanism needs to be enabled. Since the main cause of packet delay variation (PDV) is the congestion of the network node, if it can detect which node on the tunnel is congested and advertise it to the head node of the tunnel (that is, the above PTP LSP), the request header node is re-requested. Calculating the LSP path can bypass the congested nodes. Specifically, the process defined in RFC4736 may be used. The head node sends a Path message, and the Path message carries an extended congestion detection request. At this time, all nodes on the LSP that do not support the 1588 capability and the bandwidth reservation capability will enable the congestion detection function; According to the parameter configuration and QoS configuration information of the tunnel, the outbound port of the tunnel and the corresponding QoS scheduling queue can be determined, and then the congestion detection of the port and queue is enabled on the node on the LSP. Preferably, after the node that does not support the 1588 capability and the bandwidth reservation capability starts the congestion detection mechanism, the method may further include the following: the node that detects the congestion sends a path error message to the head node, where the path error message carries the detection Identification information to the node that is congested. Preferably, after the node detecting the congestion sends the path error message to the head node, the method may further include: triggering the head node to perform a re-optimization operation according to the predetermined policy; and the head node bypasses the node that detects the congestion, and reselects the PTP LSP. In the preferred implementation process, after congestion occurs, the forwarding layer notifies the MPLS TE protocol layer. According to the process defined in RFC4736, the congestion node sends an announcement message to inform the head node that congestion occurs. The head node uses a predetermined strategy to perform re-optimization path calculation, that is, On the previous tunnel path node, the congested nodes are excluded. Preferably, the foregoing predetermined policy includes, but is not limited to: determining that the triggering head node performs a re-optimization operation when the end-to-end PDV performance degradation degree and/or the packet loss rate is greater than the first threshold. The predetermined strategy for triggering the re-optimization of the head node may also cause PDV degradation due to re-optimization and handover of the intermediate network. Therefore, when the end-to-end PDV indicator meets the requirements, it is necessary to ensure the stability of the intermediate network PTP path; Only when the end-to-end PDV performance degrades to a certain extent, the head node re-optimization and switching are triggered. In addition, since the packet loss rate also reflects the congestion degree of the network, it can also be used as a trigger for re-optimization and switching of the head node. Considerations. In a preferred implementation, the tail node of the PTP LSP sends a notification message to the head node by detecting that the PDV performance degradation degree and/or the packet loss rate is greater than the first threshold, where the notification message carries the PDV performance degradation or packet loss. Wrong error code. The above preferred embodiment will be described below in conjunction with FIG. 3 is a schematic diagram of PTP path re-optimization based on congestion notification in accordance with a preferred embodiment of the present invention. As shown

As shown in 3, the head node is R1 and the tail node is R7. According to the notification result of the 1588 capability and bandwidth reservation capability of each node, the established PTP LSP is 1 1 -> R3 -> R4 -> R7. The head node sends a path message to enable congestion detection for nodes that do not support the 1588 capability and bandwidth reservation capability. The intermediate node R4 detects congestion and sends a path error message (i.e., congestion notification) to the head node. Determining the degree of PDV performance degradation and/or packet loss rate at the tail node When the threshold is greater than the predetermined threshold, a notification message is returned to the head node R1 via the path, wherein the notification message carries an error code indicating PDV performance degradation and/or packet loss error. Thereafter, the head node R1 bypasses the node R4 that detected congestion and reselects the PTP LSP. Selected? 1? 1^? is 1 1 > 1 3 -> 1 9 R7 Preferably, after the PTP LSP is selected according to the result of the notification and established, the following processing may also be included: analyzing the PDV performance on the slave device or the master device, according to the PDV performance The degree of degradation completes the protection switching of the PTP LSP or the primary clock. Since the PDV performance of the slave device is degraded due to other complicated factors of the third-party network and the clock synchronization service is not available, it is necessary to protect and switch the PTP path based on the PDV degradation. For a scenario in which multiple slave devices are synchronized to a single master device, completing the protection switch of the master device according to the PDV performance degradation degree may include the following processing:

(1) Establish a 1+1-protected PTP LSP active/standby path;

(2) analyzing the PDV jitter description of the PTP LSP active/standby path on the slave device, and selecting one of the PTP LSP active and standby paths for synchronization; (3) if the PDV performance degradation degree of the current PTP LSP is greater than the second threshold, The slave device is switched to another path in the active and standby paths of the PTP LSP.

(4) Perform a re-optimization operation on the current PTP LSP, and establish a new PTP LSP and PDV jitter description. The above preferred embodiment will be described below in conjunction with FIG. 4 is a schematic diagram of PTP path protection for a single Master in accordance with a preferred embodiment of the present invention. A single PTP path is established between each pair of master-Slave. According to the actual networking situation, the PDV performance analysis can be completed in the Slave or in the master. Then, the protection switching of the master is completed based on the PDV degradation. The specific method is as follows: Step 1: Establish a two-way PTP tunnel in the 1+1 protection mode from the master to the slave. Step 2: The master and the slave send Announce messages at both ends to establish an M/S relationship. In this case, only the receiver needs to be received and processed. The PTP process is initiated by the master device and the slave device. Step 3: The slave device receives and processes PTP packets from the two PTP LSPs simultaneously, analyzes the timestamp in the PTP packet, and establishes the PDV of the two PTP paths. Jitter description; Step 4: Slave compares the PDV jitter descriptions of the two PTP paths and selects a better PTP path for synchronization. Step 5: If the PDV degradation of the current PTP path exceeds a certain threshold, the Slave first switches to another PTP path, and then Send an advertisement packet, request the master to re-optimize the PTP path degraded by the PDV, establish a new PTP LSP and PDV jitter description, and then remove the old PPV-degraded PTP path. After re-optimization, ensure that the PDVs of the two PTP paths meet the requirements. . For a scenario in which a single slave device synchronizes to multiple master devices, the foregoing completing the protection switch of the master device according to the PDV performance degradation degree may include the following processing:

(1) A PTP LSP is established between the slave device and each master device. (2) If the PDV performance is analyzed on the slave device, the slave device compares the PDV jitter description of the established PTP LSP to select the best PDV performance. PTP LSP is synchronized;

(3) If the PDV performance is analyzed on the primary device, when the PDV performance degradation degree of the current PTP LSP is greater than the third threshold, the primary device sends a degradation notification message to the single secondary device and performs a re-optimization operation on the current PTP path, the single slave After receiving the degradation notification message, the device determines whether to switch to another master device of the plurality of master devices. The above preferred embodiment will be described below in conjunction with FIG. 5 is a schematic diagram of PTP path protection for multiple Masters in accordance with a preferred embodiment of the present invention. A single PTP path is established between each pair of Master-Slave. The impact of the load can be calculated according to the actual networking and PDV. The PDV performance analysis can be completed in the Slave or in the Master. Then, the Master protection switch is completed based on the PDV degradation. The method is as follows: Step 1: Slave establishes a two-way PTP tunnel between the masters. Step 2: The master and the slave send Announce packets to establish an M/S relationship. Then, the master device and the slave device initiate a PTP process. Step 3: If the PDV analysis is performed in the Slave, the Bayu Slave node receives and processes PTP packets from multiple Masters simultaneously, analyzes the timestamps in the PTP packets, and establishes their PDV jitter descriptions. Slave compares these PDV jitter descriptions and selects A better PTP path is synchronized; Step 4: If the PDV analysis is performed by the Master, the Master uses the IEEE 1588v2 mechanism to obtain the jitter description of the PTP path. If the PDV performance is found to be degraded, the Slave is notified and the current PTP path is re-optimized. Path, and then recalculate the PDV performance; after receiving the PDV degradation notification message, the Slave combines the clock source information and the PDV performance degradation, and adopts a certain strategy to decide whether to switch to another Masters. It should be noted that in the preferred implementation process, Extend the protocol.

(1) The congestion detection session attribute flag extension can add a new flag in the SESSION-ATTRIBUTE object in the RSVP-TE protocol. That is, when the PTP LSP is established, all the LSPs and the bandwidth reservation capability are not supported on the LSP. The node starts the congestion detection function, that is, the extended congestion detection request is carried in the path message mentioned above. And when the node is congested, the head node is advertised to the head node, and the head node re-optimizes the PTP path to bypass the congestion node; when the flag is equal to 0, the node congestion detection and congestion notification function is disabled; if the intermediate node does not support the Capability, this flag is not processed.

(2) Bandwidth reservation capability announcement

The RSVP-TE protocol layer supports the reserved bandwidth capability. However, due to the complexity and cost considerations of the hardware implementation, the intermediate network device forwarding layer does not necessarily support this capability. In addition, for the PTP service, although the protocol layer can A PTP tunnel is established, and sufficient bandwidth is reserved for this tunnel. However, if the forwarding layer cannot reserve enough bandwidth, if the node is congested, the PDV caused by the PDV will reduce the synchronization performance or even the PTP service failure. Therefore, if the network node can advertise whether the node supports bandwidth reservation capability in the entire network, a PTP path with better PDV performance can be established. Preferably, before performing the notification of the 1588 capability and the bandwidth reservation capability of each node, the following processing may be further included: an extension field in the IGP routing protocol, where the extended field is used to indicate that the notification of the bandwidth reservation capability is performed.

(3) RSVP-TE Notify message extension When the tail node detects the PDV performance degradation degree or the packet loss statistics exceeds a certain threshold, the Notify message is sent to the head node to trigger the re-optimization process; the ERROR_SPEC object in the Notify message carries the error code, which is used to Indicates PDV performance degradation or packet loss error. The above preferred embodiments are further described below in conjunction with examples. The method for selecting a PTP LSP according to an example of the present invention includes the following steps: Step A. PTP path establishment (1) The 1588 capability and the bandwidth reservation capability are advertised through the IGP routing protocol, and the node that does not support the 1588 capability and the bandwidth reservation capability is requested to enable the congestion detection function.

(2) Then run the CSPF algorithm to calculate a PTP path that bypasses the possible generation of congested nodes;

(3) The LSR head node runs RSVP-TE, and establishes a PTP path for carrying the PTP protocol. (4) The head and tail nodes run the PTP protocol, establish a master-slave relationship, and establish an end-to-end PDV jitter description; Step B. PTP Path re-optimization

(1) In the PTP path, the node that does not support the 1588 capability and the bandwidth reservation capability is enabled to detect congestion. If the node is congested, the node is notified to the RSVP-TE protocol layer.

(2) The RSVP-TE protocol sends a path error (PathErr) message to the head node to notify the node that there is congestion;

(3) After detecting that the PDV is degraded to a certain extent, the head node initiates a re-optimization process to establish a PTP path that bypasses the congestion node as much as possible; Step C. Protection of the PTP path Due to other complicated factors of the third-party network, the slave node is The performance of the PDV is degraded and the clock synchronization service is unavailable. In this case, the protection and switching of the PTP path can be performed based on the PDV degradation. To improve the synchronization performance, the PTP path can be switched and implemented according to the actual networking requirements. Optimized to ensure the availability of clock synchronization services. For a scenario where a Slave is synchronized to multiple masters, when the PTP path of the current master is degraded, the PDV is switched to the PTP path corresponding to the other master, and the master re-optimizes the PTP path. Step D. PTP protocol operation

The master and the slave device perform the frequency synchronization and time synchronization of the PTP protocol packets according to the standard of the 1588 protocol. In addition, the PDV jitter description is established through the PTP process. According to the foregoing embodiment, the PTP path that meets the requirements of the PDV is found and established on the basis of the existing device, and the PTP path is protected based on the PDV to ensure the reliability and availability of the 1588 service. FIG. 6 is a structural block diagram of a device for selecting a PTP path according to an embodiment of the present invention. As shown in FIG. 6, the PTP path selection device includes: a capability notification module 10, configured to perform notification of 1588 capability and bandwidth reservation capability of each node; and a routing module 20 configured to select a PTP LSP according to the notification result, where The number of nodes that do not support 1588 capability and bandwidth reservation capability in the selected PTP LSP is the least. In the apparatus shown in FIG. 6, the routing module 20 selects a PTP LSP according to the notification result of the capability notification module 10, which can better improve the clock recovery quality and the availability and reliability of the synchronization service. The selected PTP LSP can carry the CES service for frequency recovery, in addition to carrying the 1588 service for frequency or time recovery. Preferably, as shown in FIG. 7, the foregoing apparatus may further include: a congestion detection enabling module 30, configured to enable a congestion detection mechanism for a node that does not support the 1588 capability and the bandwidth reservation capability. Preferably, as shown in FIG. 7, the apparatus may further include: a PDV performance analysis module 40 configured to analyze PDV performance on the slave device or the master device; and a protection switching module 50 configured to complete the PTP LSP according to the PDV performance degradation degree or The protection switch of the master clock. It should be noted that the preferred embodiments of the modules in the above-mentioned devices are specifically referred to the descriptions of FIG. 2 to FIG. 5 , and details are not described herein again. In summary, with the above embodiments provided by the present invention, a PTP traverses a third-party MPLS network, and an optimized PTP LSP is established in the MPLS network, and the PTP path is analyzed by analyzing PDV performance at both ends of the master-slave clock device. Re-optimization and PTP path switching; In addition, it is also proposed to perform PDV performance analysis in Slave or Master in multiple Master scenarios, and Slave switches the Master based on PDV performance. With the above embodiments, clock recovery can be better improved. Quality and synchronization of business availability and reliability. Obviously, those skilled in the art should understand that the above modules or steps of the present invention can be implemented by a general-purpose computing device, which can be concentrated on a single computing device or distributed over a network composed of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device so that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or Multiple modules or steps are made into a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software. The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention, and various modifications and changes can be made to the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

1. A precise timing protocol PTP label switching path LSP selection method, including:

Perform notification of 1588 capability and bandwidth reservation capability of each node;

The PTP LSP is selected according to the result of the notification, and the number of nodes that do not support the 1588 capability and the bandwidth reservation capability in the selected PTP LSP is the least.

2. The method according to claim 1, wherein the selected PTP LSP supports 1588 service and circuit emulation service CES.

3. The method according to claim 1, wherein after selecting the PTP LSP according to the notification result, the method further comprises:

For nodes that do not support the 1588 capability and bandwidth reservation capability, the congestion detection mechanism is enabled.

4. The method of claim 3, wherein for a node that does not support 1588 capability and bandwidth reservation capability, enabling congestion detection mechanisms includes:

A header node in the PTP LSP sends a path message, where the path message carries a congestion detection request.

After receiving the path message, the node that does not support the 1588 capability and the bandwidth reservation capability in the PTP LSP starts the congestion detection mechanism.

The method according to claim 4, wherein after the node that does not support the 1588 capability and the bandwidth reservation capability turns on the congestion detection mechanism, the method further includes:

The node detecting the congestion sends a path error message to the head node, where the path error message carries the identification information of the node that detects the congestion.

The method according to claim 5, wherein after detecting that the node that is congested sends a path error message to the head node, the method further includes:

Triggering the head node to perform a re-optimization operation according to a predetermined policy;

The head node bypasses the node that detects congestion and reselects the PTP LSP.

7. The method according to claim 6, wherein the predetermined policy comprises:

When the end-to-end PDV performance degradation degree and/or the packet loss rate is greater than the first threshold, it is determined that the trigger head node performs a re-optimization operation.

8. The method according to claim 7, wherein the triggering the head node to perform the re-optimization operation comprises one of: the tail node of the PTP LSP determines, by detecting, that the PDV performance degradation degree and/or the packet loss rate is greater than the The first threshold sends a notification message to the head node, where the notification message carries an error code for indicating PDV performance degradation and/or packet loss error.

The method according to any one of claims 1 to 8, wherein after selecting and establishing the PTP LSP according to the notification result, the method further comprises: analyzing the PDV performance on the slave device or the master device according to the PDV performance degradation degree Complete protection switching of the PTP LSP or the primary clock.

10. The method according to claim 9, wherein, for a scenario in which a plurality of slave devices are synchronized to a single master device, completing the protection switching of the master device according to the PDV performance degradation degree comprises:

Establish a 1+1-protected PTP LSP active and standby path.

The PDV jitter description of the PTP LSP active and standby paths is analyzed on the slave device, and the PTP is selected.

Synchronize one path in the active and standby paths of the LSP.

If the PDV performance degradation degree of the current PTP LSP is greater than the second threshold, the slave device switches to another path in the PTP LSP active/standby path.

Performing a re-optimization operation on the current PTP LSP, establishing a new PTP LSP and a PDV jitter description.

11. The method according to claim 9, wherein, for a scenario in which a single slave device synchronizes to a plurality of master devices, completing the protection switch of the master device according to a PDV performance degradation degree comprises:

Establish a PTP LSP between the slave device and each master device.

If the PDV performance is analyzed on the slave device, the slave device compares the PDV jitter description of the established PTP LSP, and selects a PTP LSP with the best PDV performance for synchronization;

If the PDV performance is analyzed on the primary device, when the PDV performance degradation degree of the current PTP LSP is greater than a third threshold, the primary device sends a degradation notification message to the single secondary device and performs a re-optimization operation on the current PTP path, the single After receiving the degradation notification message from the device, it is determined whether to switch to another of the plurality of primary devices.

The method according to claim 1, wherein before performing the notification of the 1588 capability and the bandwidth reservation capability of each node, the method further includes: extending an field in the IGP routing protocol, where the extended field is used to indicate The notification of bandwidth reservation capability is performed.

13. A device for selecting a PTP LSP, comprising: The capability notification module is configured to perform the notification of the 1588 capability and the bandwidth reservation capability of each node. The routing module is configured to select the PTP LSP according to the notification result, where the selected PTP LSP does not support the 1588 capability and the bandwidth reservation. The number of nodes with the least capacity is the least.

14. The device according to claim 13, further comprising:

The congestion detection enablement module is set to enable the congestion detection mechanism for nodes that do not support the 1588 capability and bandwidth reservation capability.

The device according to claim 13 or 14, further comprising:

The PDV performance analysis module is configured to analyze PDV performance on the slave device or the master device; the protection switch module is set to perform protection switching of the PTP LSP or the master clock according to the PDV performance degradation degree.