WO2011011932A1

WO2011011932A1 - Method for processing precision time protocol message and apparatus thereof

Info

Publication number: WO2011011932A1
Application number: PCT/CN2009/073794
Authority: WO
Inventors: 杨元永; 宿飞
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-07-27
Filing date: 2009-09-07
Publication date: 2011-02-03
Also published as: CN101616163B; CN101616163A

Abstract

A method for processing precision time protocol (PTP) message and the apparatus thereof are disclosed in the invention. The method is used to process PTP message in a looped network composed of transparent clocks, which includes the following steps: running multiple spanning trees protocol (MSTP) on each transparent clock in the network, selecting the state of each port using PTP on each transparent clock, processing the PTP message according to the port state selected by running the MSTP and the type of the PTP message to be processed, and forwarding the processed PTP message only on the port in the state of transmitting. By the invention, the PTP message can be prevented from forming a loop.

Description

The present invention relates to the field of mobile communications technologies, and in particular, to a method and apparatus for processing a precise time transfer protocol message. BACKGROUND Currently, there are two types of synchronization between devices in a communication network: One is frequency synchronization, that is, signals at the source end and the destination end maintain a certain relationship in frequency or phase, and frequency synchronization can also be referred to as time 4 Synchronization, for example, synchronous Ethernet, E1 interface, 4 synchronization, etc.; Another synchronization is time synchronization, that is, the source and destination are not only the same frequency, but also the same phase, and have the same time count scale. For frequency synchronization, each network element node can be locked by clock synchronization signals (such as synchronous Ethernet, etc.). Each network element node clock and other fixed frequency sources together form a frequency (or clock) synchronization network. For time synchronization, the main implementation methods include: Global Position System (GPS) 4 time-dependent or using time synchronization protocol (for example, IEEE Std 1588TM - 2008, etc.) to adjust master time 4 and slave time Time offset between 4, achieving time synchronization. Moreover, the time synchronization protocol can also achieve frequency synchronization between the master clock and the slave clock. At present, the Packet Transport Network (PTN) device mainly implements frequency synchronization and time synchronization in the network through the IEEE Std 1588TM - called PTP to solve the replacement problem of the base station GPS.

The basic function of PTP is to keep the clocks of each node in the distributed network and keep the clock and time synchronized within a certain precision. 1588v2 provides three basic clock types that can be used for networking between master and slave clocks: boundary clock, end-to-end (E2E) transparent clock, and point-to-point (point to point). ) Transparent clock. In a distributed network, three types of clocks can be mixed, but in the case of networking, if a plurality of transparents form a ring structure between the four, the node itself has a function of being transparent. The Best Master Clock (BMC) algorithm does not run the best master clock (BMC) algorithm. After the packet is processed, the packet is forwarded. Therefore, the PTP packet is looped, causing network storms. SUMMARY OF THE INVENTION In view of the above, the present invention provides an improved PTP message processing method and apparatus for solving the problem of PTP 4 成成由于由于由于。。。。。。。。。。。。。。。。。 According to an aspect of the present invention, an accurate PTP message processing method is provided for processing a PTP 4 message in a looped network composed of transparent clocks. The method for processing an accurate PTP 4 file according to the present invention includes: running a multiple spanning tree protocol (MSTP) on each transparent clock in the foregoing network, and selecting a state of each port on which each PTP protocol is enabled on a transparent clock; Each of the transparent clocks processes the PTP 4 message according to the state of the port selected by the MSTP protocol and the type of the PTP 4 message to be processed, and forwards the processed PTP only on the port in the sending state. Text. Preferably, the status of the port includes one of the following: a disabled state, a listening state, a learning state, a sending state, and a blocking state. Preferably, the MSTP protocol is run on each of the transparent clocks to select a dog state of each port on which the PTP protocol is enabled on each transparent clock, including: creating, for each transparent clock, an instance of a predetermined virtual local area network, where the virtual local area network The port that runs the PTP protocol with the link link on the transparent clock. The MSTP protocol is run on each transparent clock, and the state of a port on the link in which the PTP 4 is looped in the network is set based on the created instance. Is blocked. Preferably, the above-mentioned virtual local area network is dedicated to PTP. Preferably, the PTP 4 message to be processed includes: a PTP 4 message generated by the transparent clock and/or a PTP 4 message received by the transparent clock. Preferably, when the topology of the network changes, the method further includes: automatically running the MSTP protocol again on each transparent clock in the network, and reselecting the states of the ports on the transparent clocks. According to another aspect of the present invention, there is provided a PTP 4 file processing apparatus located at a node having a transparent clock function. The PTP message processing apparatus according to the present invention includes: an MSTP protocol module, a PTP protocol module, and a PTP 4 艮 message forwarding module. The MSTP protocol module is configured to generate and run the MSTP protocol, and determine the status of each port of the node that is enabled with the PTP protocol. The PTP protocol module is configured to determine the status of each port and the PTP according to the MSTP protocol module. The PTP message forwarding module is configured to forward the PTP message processed by the PTP protocol module on the port in the sending state. Preferably, the status of the port includes one of the following: a disabled state, a listening state, a learning state, a sending state, and a blocking state. With the above at least one aspect of the present invention, by running the MSTP protocol on each node having a transparent clock function in a loop-shaped network composed of a transparent clock, the state of each port on which the PTP protocol function is enabled on each transparent clock can be selected. Each transparent clock processes the PTP 4 message according to the state of the selected port, and only forwards the PTP 4 message on the port in the sending state, thereby preventing the PTP 4 message from being looped. Other features and advantages of the invention will be set forth in the description which follows, and The objectives and other advantages of the invention will be realized and attained by the <RTI The drawings are intended to provide a further understanding of the invention, and are intended to be a part of the description of the invention. 1 is a flow chart of a PTP 4 艮 message processing method according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a network composed of a transparent clock in the first embodiment; FIG. 3 is a schematic diagram of a mesh network in the second embodiment; 4 is a schematic structural diagram of a network structure of a third embodiment; FIG. 5 is a schematic structural diagram of a PTP packet processing apparatus according to an embodiment of the present invention; FIG. 6 is a specific implementation of a PTP packet processing apparatus according to an embodiment of the present invention; Schematic diagram of the structure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A function of a node with a transparent clock function does not run the BMC algorithm. Therefore, if a ring structure is formed between multiple transparent clocks during networking, the PTP 4 message will be looped. The embodiment of the invention provides an improved PTP 4 message processing scheme. In the embodiment of the present invention, in a looped network composed of a transparent clock, if there is a PTP 4 转发 forwarding loop, each node having a transparent clock function runs the MSTP protocol to create an MST instance, the MST. The instance corresponds to a dedicated PTP 4 virtual local area network or virtual network (Virtual Local Area Networks, called a VLAN), the VLAN contains PTP ports in the transparent 4 . By running MSTP 10, the node with transparent clock function will determine which port is disconnected on the loop. The status of the port determined by running MSTP is VLAN-based. The corresponding VLAN is a special VLAN and is used for PTP. Therefore, the status of the determined port is only for PTP. It works, other agreements are not affected. The embodiments in the present application and the features in the embodiments may be combined with each other without conflict. The preferred embodiments of the present invention are described in the following with reference to the accompanying drawings, which are intended to illustrate and illustrate the invention. According to an embodiment of the present invention, a PTP packet processing method is first provided, and the method is used to process a PTP packet in a looped network composed of transparent clocks. 1 is a flowchart of a PTP 4 message processing method according to an embodiment of the present invention. As shown in FIG. 1, the PTP 4 file processing method according to an embodiment of the present invention mainly includes the following steps (step S101 - steps) S103): Step S101: Run MSTP on each transparent clock in the network, and select a state of each port on which PTP 10 is enabled in each transparent time; specifically, create an instance for each transparent clock. The VLAN corresponding to the created instance is a predetermined VLAN (that is, a pre-negotiated VLAN). The port included in the VLAN is a port running the PTP protocol with a link link on the transparent clock. Run the MSTP protocol to set the state of a port on the link that is a ring of PTP packets on the network to the blocked state based on the created instance. Specifically, the status of the port includes, but is not limited to, a prohibited state, a listening state, a learning state, a sending state, and a blocking state. In the embodiment of the present invention, only the port in the transmitting state can forward the PTP message. Step S103: For each transparent clock in the network, the PTP 4 message is processed according to the state of the port selected by the MSTP protocol and the type of the PTP 4 message to be processed, and only after the forwarding process is performed on the port in the sending state. PTP message. On all transparent clocks in the network, when there are 4 files to be processed, the type of 4艮 is first determined. If it is a PTP packet, it is determined according to the type of the clock of the node (that is, the boundary clock, the normal clock, the transparent clock) and the type of the PTP 4 message, whether the message should be sent to the PTP protocol stack, or whether it is based on the MSTP. The selected port status is used to process the PTP 4 message. If the port status selected by the MSTP is processed, the port status selected by the MSTP protocol and the PTP 4 message type are processed, and the PTp_3⁄4 text is processed. If it is a different protocol, it will be processed separately. For example, 4 files will be sent to other protocol stack components for processing. Specifically, the processed 包括艮包括包括包括包括包括包括包括包括包括包括透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明透明。。。 When PTP 4 messages are processed according to the port status judged by the MSTP, PTP packets are forwarded only on the port whose state is determined by the MSTP. The PTP packets are not forwarded on the ports in other states. Thus, PTP 4 is avoided. And the port dog state selected by MSTP 10 only works for PTP 4, and does not affect other protocol messages. Moreover, in the embodiment of the present invention, when the topology of the network changes, the state of each port on each transparent clock may be re-selected on each transparent clock in the network through the MSTP protocol. The following description will be made by way of specific examples. Embodiment 1 This embodiment uses a network composed of a transparent clock as shown in FIG. 2 as an example. As shown in FIG. 2, in the network, a port with a normal clock (OC) and a P2P transparent clock (P2P TC) 1 is connected. As the master (MASTER) port, it initiates PTP synchronization (Sync) 4 and PTP point-to-point delay request (Pdelay-Rep), and responds to Pdelay-Req. In Figure 2, all connected ports on the P2P transparent clock (P2P TC) will forward the Syn 4 message and initiate Pdelay-Rep. 艮文, and respond to Pdelay-Req 4 艮文. In FIG. 2, the three P2P TCs constitute a PTP 4 艮 text loop, and then the PTP 4 艮 text processing method according to the embodiment of the present invention performs the following processing on the network in this embodiment:

(1) MSTP is enabled on all P2P transparent clocks in the figure to create an instance. The VLAN corresponding to the created instance is a special VLAN with a good quotient. The port included in the VLAN is the port with the link link on the P2P transparent clock (the port must be the port running PTP). Through the operation of the MSTP protocol on all P2P transparent clocks in the figure, the status of each port on each P2P transparent clock (including: forbidden, listening, learning, sending, and blocking) is selected, that is, the PTP packet is looped in the figure. A port state on the link is set to a blocking state. (2) On all P2P transparent clocks in the model, first determine the type of message to be processed. If it is a PTP packet, it is judged whether it should be sent to the PTP protocol stack according to the clock type (boundary clock, normal clock, transparent clock) of the node and the type of PTP message, or is it judged according to MSTP. The port state handles PTP 4 艮 text. If it is sent to the PTP protocol stack, the PTP 4 message is processed according to the port status selected by the MSTP protocol and the PTP 4 message type. If it is a different protocol, it will be processed separately. For example, 4 baht is sent to other protocol stack components for processing.

(3) Only the port whose port status is the sending status judged by the MSTP forwards the PTP 4 message, and the port in other status does not forward the PTP 4 message. Embodiment 2 This embodiment describes a technical solution provided by an embodiment of the present invention by taking the mesh network shown in FIG. 3 as an example. Specifically, the method includes the following steps: Step 1: The normal clock 1-1 acts as the MASTER port of the grandfather clock on the link A, and actively initiates the Sync 4 message and the Pdelay Rep 4 message, and responds to the Pdelay-Req 4 Yan Wen. The other common clocks in the figure are used as the slave clocks, and the time is synchronized with the normal clock 1-1; Step 2, after receiving the Sync message on the link A, the P2P transparent clock 1-1 is forwarded to the two links B and C; After receiving the Pdelay-Req 4 message, it is sent to the PTP protocol stack module for processing. At the same time, the node clock sends Pdelay-Req 4 messages on links A, B and C. The processing of other P2P transparent clocks in the figure is similar to that of the P2P transparent clock 1-1, and is not described here again, so that the transparent clock in the network constitutes a ring network, for example, a P2P transparent clock 1-1, 1-2, 2-1, and 2-2 form the PTP 4 艮 text loop. Step 3: MSTP is enabled on all the transparent clocks of the network, and the VLANs corresponding to the created instances are pre-negotiated special VLANs. The port included in the VLAN is a port with a link link on the P2P transparent clock. For example, for P2P transparent, when 1 - 1 is in 4, the corresponding VLAN contains the port A,

Three ports on B and C. After the MSTP protocol is running on all P2P transparent clocks in the network, the state of a port on the link in which the PTP packet is looped is set to the blocking state. Step 4: On all P2P transparent clocks in the network, according to the port state selected by the MSTP protocol and the PTP 4 port type, the PTP 4 message is processed, specifically, on each P2P transparent clock, only for sending The port of the state only forwards the PTP 4 message, and the port of the other state does not forward the PTP message, so that the PTP 4 message can be avoided. In addition, the port status selected by the MSTP protocol only works for PTP packets, so it does not affect other protocol packets. Step 5: If the topology of the network changes, running MSTP will re-select the state of each port on each P2P transparent clock node. Embodiment 3 This embodiment describes the technical solution provided by the embodiment of the present invention by taking the network structure shown in FIG. 4 as an example. As shown in FIG. 4, in the network shown in FIG. 4, the convergence ring devices 1 and 2 are set to the boundary clock function, and the devices 3, 4, and 5 are set to the transparent clock function (for example, the P2P transparent clock), and all devices of the access ring are set. Both are set to transparent clock functions (for example, P2P transparent clock). Moreover, a TD base station is hung under the access ring device, and each TD base station has a common clock function. All PTP devices use the one-step clock mode defined by 1588v2. According to the technical solution provided by the embodiment of the present invention, for the network shown in FIG. 4, when the network is a PTP, the i or JLi or the delay measurement mechanism is the Peer delay mode, and the network is also an MSTP i. or. Its processing mainly includes:

(1) In this clock domain, both the boundary clock and the normal clock, the BMC algorithm is enabled.

(2) The time source of boundary clock 1 is from GPS, which is the GM clock of the PTP domain. According to the BMC algorithm, the port on the link acts as the MASTER port, and actively initiates the Sync 4 message and Pdelay Rep 4, and in response to Pdelay-Req 4 ,, other common clocks in the model are used as slave clocks according to the BMC algorithm, and time is synchronized to boundary clock 1.

(3) In the access ring 1, the transparent clock 3 receives the Sync message on the link connected to the boundary clock 2, and then forwards it to the other four links. If the Pdelay-Req message from 2 is received, It is sent to the PTP protocol stack module for processing; at the same time, the node clock sends Pdelay-Req 4 messages on all links, and the processing of other P2P transparent clocks in the network model is similar to the P2P transparent clock 3. The transparent clock in the model forms a ring structure, for example, when the access ring is transparent, 4, 3, 1-1, 1-2, 1-3, 1-4, 1-5, 1-6, and 1-7 The PTP 4 艮 text loop is constructed.

(4) The MSTP protocol is enabled on all the P2P transparent clocks in the network model, and the VLANs corresponding to the instances created in the MSTP protocol are pre-negotiated special VLANs. The ports included in the VLAN are P2P transparent. A port with a link link on the clock. For example, for P2P transparent clock 3, its corresponding VLAN contains five ports on all links. After the operation of the MSTP protocol on all P2P transparent clocks in the network model, a port state on the link in which the PTP packet is looped is set to a blocking state in the model, so that the ring link is disconnected, for example, disconnected. The link between the transparent clocks 1-3 and 1-4 of the ring I is accessed.

(5) On each P2P transparent clock in the mode network type, each P2P transparent clock processes the PTP file according to the port state selected by the running MSTP protocol and the type of the PTP 4 message to be processed. Specifically, for each P2P transparent clock, only the port that is in the sending state forwards the PTP message, and the ports in other states do not forward the PTP message.

(6) In this model, if the network topology changes, the MSTP protocol will re-determine the state of each port on each P2P transparent clock node, and the BMC algorithm running on the boundary clock and the ordinary clock will also Reselect the PTP port status. According to an embodiment of the present invention, there is also provided a PTP text processing apparatus, the apparatus being located at a node having a transparent clock function. FIG. 5 is a schematic structural diagram of a PTP packet processing apparatus according to an embodiment of the present invention. As shown in FIG. 5, a PTP packet processing apparatus according to an embodiment of the present invention mainly includes: an MSTP protocol module 1, a PTP protocol module 3, and a PTP 4.艮文 forwarding module 5. The MSTP protocol module 1 is configured to generate and run the MSTP protocol, and determine the state of each port of the node; the PTP protocol module 3, The PTP 4 转发 message forwarding module 3 is configured to forward the PTP processed by the PTP protocol module 3 on the port in the sending state according to the state of each port determined by the MSTP protocol module 1 and the type of the PTP message. 4 艮文. Specifically, the status of the foregoing port includes, but is not limited to, one of the following: a disabled state, a listening state, a learning state, a sending state, and a blocking state. In a specific implementation process, the foregoing device may be implemented by using a transparent system as shown in FIG. 6. As shown in FIG. 6, the transparent clock system mainly includes: 1588 protocol stack 61, MSTP protocol stack 63, and other protocol stacks. 65 and protocol 4 extraction and processing module 67. The MSTP protocol stack 61 is used to: 1) generate and process the MSTP protocol, 2) run the MSTP protocol, determine the state of each port on the device in the network; 1588 protocol stack 63 is used to generate and process the PTP 4 message; other protocols The stack 65 is used to generate and process non-PTP messages; the protocol message extraction and processing module 67 is used to determine the type of the message, and the corresponding processing according to different types. As described above, with the technical solution provided by the embodiment of the present invention, the link of the PTP packet to be looped can be disconnected between the transparent clock nodes without affecting the delivery of the non-PTP packet. In addition, in the embodiment of the present invention, when the network topology is changed, the PTP packet transmission link can be updated in time without causing abnormality in PTP packet transmission. In addition, the solution provided by the embodiment of the present invention can be used simultaneously with the BMC algorithm, and can be applied to the scenario where the boundary clock and the transparent clock are mixed, effectively preventing the PTP 4 from being looped, and implementing the synchronization path protection. The above is only the preferred embodiment of the present invention, and is 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 scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim

A method for processing a PTP 4 packet in a ring-shaped network composed of transparent clocks, wherein the method comprises: in the network The multi-spanning tree protocol MSTP is run on each transparent clock to select the state of each port on the transparent clock that is enabled with the PTP protocol.

For each transparent clock in the network, the PTP 4 message is processed according to the state of the port selected by the MSTP protocol and the type of the PTP 4 message to be processed, and is only forwarded on the port in the sending state. The PTP 4 after processing.

2. The method according to claim 1, wherein the state of the port comprises the following: a prohibited state, a listening state, a learning state, a sending state, and a blocking state.

The method according to claim 2, wherein the MSTP protocol is run on each of the transparent clocks, and the states of the ports on which the PTP protocol is enabled on each transparent clock are selected: for each transparent clock, a reservation is created. An example of a virtual local area network, where the virtual local area network includes a port running the PTP protocol with a link link on the transparent clock; by running the MSTP protocol on each transparent clock, based on the created instance, the PTP 4 in the network is The state of a port on the link of the ring is set to the blocked state.

The method according to claim 3, wherein the virtual local area network is dedicated to PTP messages.

The method according to claim 1, wherein the PTP message to be processed comprises: a PTP message generated by the transparent clock and/or a PTP message received by the transparent clock.

The method according to any one of claims 1 to 5, wherein when the topology of the network changes, the method further includes:

The MSTP protocol is automatically run again on each transparent clock in the network, and the state of each port on each transparent clock is reselected. A PTP 4 艮处理 processing device, located in a node having a function of being transparent 4, wherein the device comprises:

The MSTP protocol module is configured to generate and run the MSTP protocol, and determine that the node enables the state of each port that is discussed by the tenth node;

a protocol module, configured to process the PTP 4 according to the status of each port determined by the MSTP protocol module and the type of the PTP 4 message;

The PTP file forwarding module is configured to forward the PTP packet processed by the PTP protocol module on the port in the sending state. The device according to claim 7, wherein the state of the port comprises the following

—: Disable status, listening status, learning status, sending status, and blocking status.