CN100571115C - A kind of method for synchronous and system - Google Patents

A kind of method for synchronous and system Download PDF

Info

Publication number
CN100571115C
CN100571115C CNB2006100784175A CN200610078417A CN100571115C CN 100571115 C CN100571115 C CN 100571115C CN B2006100784175 A CNB2006100784175 A CN B2006100784175A CN 200610078417 A CN200610078417 A CN 200610078417A CN 100571115 C CN100571115 C CN 100571115C
Authority
CN
China
Prior art keywords
network element
clock
essm
source
clock source
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CNB2006100784175A
Other languages
Chinese (zh)
Other versions
CN101043316A (en
Inventor
王仁哲
辛桂珍
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Huawei Technologies Co Ltd
Original Assignee
Huawei Technologies Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Huawei Technologies Co Ltd filed Critical Huawei Technologies Co Ltd
Priority to CNB2006100784175A priority Critical patent/CN100571115C/en
Publication of CN101043316A publication Critical patent/CN101043316A/en
Application granted granted Critical
Publication of CN100571115C publication Critical patent/CN100571115C/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0658—Clock or time synchronisation among packet nodes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/06—Synchronising arrangements
    • H04J3/0635—Clock or time synchronisation in a network
    • H04J3/0638—Clock or time synchronisation among nodes; Internode synchronisation
    • H04J3/0641—Change of the master or reference, e.g. take-over or failure of the master
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J3/00—Time-division multiplex systems
    • H04J3/02—Details
    • H04J3/12—Arrangements providing for calling or supervisory signals

Abstract

The invention discloses a kind of method for synchronous, comprising: the weights of the link that first each port of network element setting and its in the packet switching network links to each other, and the expansion Synchronization Status Message ESSM of this network element of initialization; Described first network element sends ESSM to the second coupled network element; Described second network element redefines ESSM according to the weights of the link of port and the ESSM of reception; Described second network element is selected the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that redefines, and the clock source among the ESSM that selects is set to the timing reference input of this network element; The ESSM that selects is issued the 3rd network element that links to each other with second network element, is the ESSM of DNU to the first network element tranmitting data register quality; The invention also discloses a kind of network element and network system.The present invention can select rational timing reference input, and can avoid clock loop or lock rudimentary clock problem.

Description

A kind of method for synchronous and system
Technical field
The present invention relates to a kind of network communications technology, relate in particular to a kind of method for synchronous and system.
Background technology
Development along with data service and third generation wireless network, make by PSN (Packet SwitchNetwork, packet switching network) transmits TDM (Time Division Multiplex, time division multiplexing) demand of business and clock synchronization information is more and more urgent, address these problems, an effective and efficient manner makes PSN physical layer synchronization transmission clock information exactly.
SSM (Synchronizatio Statue Message, Synchronication status message) is mainly used in SDH (Synchronous Digital Hierarchy, Synchronous Digital Hierarchy) in the network, it mainly comprises clock stratum information, transmit by the S1 byte in STM-N (rank is the synchronous transfer mode of the N) frame, select the clock source for downstream network element reference is provided, and guarantee that by the mode of the DNU of network element loopback upstream (Do Not Use, forbidding) clock does not become loop and do not lock rudimentary clock.
Place OAMPDU (OAM (operation, management, maintenance) protocol Data Unit) to transmit SSM information in the existing standard, OAMPDU is the ethernet mac frame of a standard.Similar among SSM usage and the SDH (SONET).Being defined as follows of this frame:
Describe (Description) Eight hytes (Octets)
Destination address (Destination address) 1-6
Source address (Source address) 7-12
The OAMPDU length/type (OAMPDU Length/Type) 13-14(Slow protocol type field value 8809)
OAMPDU somatotype (OAMPDU subtype) 15(Identification of slow protocol being encapsulated for OAMPDU＝0x03)
Sign (Flags) 16-17
Coding (Code) 18(Identifies specific OAMPDU type set to FE)
Mechanism's unique identifier (OUI) 19-21
Synchronication status message (SSM) 22
Keep (Reserved) 23-61
Frame check order (Frame Check Sequence) 61-64
Prior art just places an ethernet mac frame to transmit traditional SSM information, SSM information has only three kinds of clock stratum among traditional SDH, be PRC (Primary Reference Clock, the source reference clock), SSU (primary level SSU, first order synchronization supply unit), SEC (SDH EquipmentClock, SDH equipment clock), if it directly is used in the existing Ethernet, then need each network element to support SEC rank clock at least, this mode cost is too high; And the SSM application scenarios of traditional SDH mainly is chain or loop network; if its occupation mode is not improved in the PSN network that directly is used in MESH (netted) structure; network configuration mode meeting more complicated; be easy to generate such as clock loop or lock problems such as rudimentary clock, and do not support the multiple spot fail safe.
Summary of the invention
The purpose of this invention is to provide a kind of method for synchronous and system, make clock that network element in the PSN network can select highest level in the network,, and avoid clock tracing Cheng Huan so that realize clock synchronization and clock chain circuit protection as the reference source.
The invention discloses a kind of method for synchronous, comprising:
The weights of the link that A, first each port of network element setting and its link to each other, and the expansion Synchronization Status Message ESSM of this network element of initialization, described ESSM comprises protection information, clock quality, clock quality priority and clock weight information;
B, described first network element send ESSM to the second coupled network element;
C, described second network element redefine ESSM according to the weights of the link of port and the ESSM of reception;
D, described second network element are selected the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that redefines, and the clock source among the ESSM that selects is set to the timing reference input of this network element; The ESSM that selects is issued the 3rd network element that links to each other with second network element, is the ESSM of DNU to the first network element tranmitting data register quality;
E, described the 3rd network element are according to clock weight addition among the ESSM of the weights of the link of port and reception, redefine the clock weight of new ESSM, described the 3rd network element is selected the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that redefines, pre-defined rule is adjudicated for carrying out ESSM priority according to protection information, clock quality, clock quality priority and clock weight information successively, and the clock source among the ESSM that selects is set to the timing reference input of this network element; The ESSM that selects is issued the 4th network element that links to each other with the 3rd network element, to the ESSM of the second network element tranmitting data register quality for forbidding DNU.
Described step B specifically comprises: described first network element after the network element initialization or the scheduled time of being separated by send ESSM to coupled second network element.
Described protection information comprises tracking mode and standby clock reference source.
The ESSM of described this network element of network element initialization specifically comprises:
When network element was clock source access network element, the tracking mode of protection information was set to effectively, and clock quality and clock quality priority are set to the clock quality and the clock quality priority of the reference source of clock;
When network element was non-clock source access network element, the tracking mode of protection information was set to effectively, and clock quality and clock quality priority are set to synchronous ethernet network element clock and priority arbitrarily.
The highest ESSM of its clock source priority of described selection specifically comprises:
If the tracing source state of protection information is invalid among a certain road ESSM that network element is received; then the timing reference input of this network element remains unchanged; when the clock source in the ESSM that is received is consistent with the standby clock reference source in the protection information; then select clock source among this ESSM as the timing reference input of this network element; otherwise, utilize clock quality, clock quality priority and clock weight information to select the clock source.
Described clock quality, clock quality priority and the clock weight information of utilizing selects the clock source specifically to comprise:
S1, from the ESSM of all receptions, select the highest clock source of clock quality, if the highest clock source of clock quality is one, then select the timing reference input of this clock source as this network element, otherwise, execution in step S2,
S2, from the highest clock source of clock quality, select the highest clock source of clock quality priority,, then select the timing reference input of this clock source as this network element if the clock source of selecting is one, otherwise, execution in step S3,
Select the clock source of the weights minimum of link in S3, the clock source from step S2, selected, if the clock source of selecting is one, then select the timing reference input of this clock source as this network element, otherwise, the timing reference input of any one clock source selected as this network element.
Described clock quality comprises source reference clock, first order synchronization supply unit, SDH equipment clock, synchronous ethernet network element clock and forbidding, and its priority orders is source reference clock＞first order synchronization supply unit＞SDH equipment clock＞synchronous ethernet network element clock＞forbidding.
The described ESSM of redefining specifically comprises:
Among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port.
Described method also comprises: be provided with the timing reference input table in the network element that the clock source links to each other, described timing reference input table comprises: the clock quality priority in the MAC Address of the network element that links to each other with the clock source, the clock quality in clock source and clock source.
Described method also comprises: the network element that links to each other with the clock source determines according to the timing reference input table whether this network element is the network element that links to each other with timing reference input and the network element that links to each other with the standby clock reference source of present networks.
Described method also comprises:
When network element is with timing reference input links to each other network element, if during NE Discovery timing reference input fault, then network element the tracking mode of the protection information of ESSM is made as invalid;
When network element is with the standby clock reference source links to each other network element, if NE Discovery is during with network element failure that timing reference input links to each other, then network element the tracking mode of the protection information of ESSM is made as invalid.
The present invention also discloses a kind of network element, comprising:
Initialization unit is used to calculate the weights of the link that links to each other with each port of this network element, and the expansion Synchronization Status Message ESSM of this network element of initialization, and described ESSM draws together protection information, clock quality, clock quality priority and clock weight information;
Transmitting element is used for sending ESSM to the network element that links to each other with this network element;
Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port;
Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then;
Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, be the ESSM of DNU to the network element tranmitting data register quality of the ESSM that sends described selected cell selection.
Described network element can link to each other with the clock source.
The invention also discloses a kind of network system, it comprises: clock source network element, and it links to each other and common network element with the clock source, and it does not link to each other with the clock source; Described clock source network element links to each other with common network element, and described network element comprises:
Initialization unit is used to calculate the weights of the link that links to each other with its each port, and the expansion Synchronization Status Message ESSM of this network element of initialization, and described ESSM draws together protection information, clock quality, clock quality priority and clock weight information;
Transmitting element is used for sending ESSM to the network element that links to each other with this network element;
Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port;
Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then;
Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, be the ESSM of DNU to the network element tranmitting data register quality of the ESSM that sends described selected cell selection.
Described network element also is provided with the timing reference input table, and described timing reference input table comprises: the clock quality priority in the MAC Address of the network element that links to each other with the clock source, the clock quality in clock source and clock source.
According to the present invention, owing to comprised synchronous ethernet network element clock among the ESSM, make the ESSM bag be applicable to the clock stratum of PSN (as Ethernet), be convenient to select rational timing reference input and timing allocation.In addition,, can avoid clock loop with comparalive ease or lock rudimentary clock problem owing to comprise the weights of the link of network in the ESSM information, and the link protection when providing a plurality of reference sources to lose efficacy.
Description of drawings
Fig. 1 shows the flow chart of the method for synchronous of the embodiment of the invention;
Fig. 2 shows the decision method of the ESSM priority of the embodiment of the invention;
Fig. 3 a-3e shows the clock distribution schematic diagram of the embodiment of the invention;
Clock distribution schematic diagram when break down in the clock source that Fig. 4 a-4d shows the embodiment of the invention;
Fig. 5 shows the structural representation of the network element of the embodiment of the invention.
Embodiment
Understand and realization the present invention the existing embodiments of the invention of describing in conjunction with the accompanying drawings for the ease of persons skilled in the art.
Basic thought of the present invention is that (that is, ESSM) information makes that the network element in the PSN network is selected correct reference clock according to ESSM, thereby realizes clock synchronization and clock chain circuit protection, and avoids clock tracing Cheng Huan to transmit expansion SSM in the PSN network.Described ESSM expands the clock quality grade by the SSM information to traditional SDH, and protection information, clock priority, two information of clock weight obtain during increase.Below in conjunction with accompanying drawing the present invention is described.
The definition of ESSM information is at first described.Table 1 shows mac frame of the present invention, comprising to the ESSM information definition.
Table 1
Figure C20061007841700111
As shown in table 1, according to the present invention, ESSM message comprises PM (protection information), SSM, PRI (clock priority) and AM (clock weight), describes PM, SSM, PRI and the AM information of forming ESSM below in detail, and it is defined as follows:
(1) PM information, this information are protection information; it comprises tracing source state and standby reference source information; if current tracing source state is invalid; the tracing source fault then is described; this moment, this network element kept present tracking mode constant; when having the clock source signals that is complementary with standby reference source information to arrive, just select to switch,, follow the tracks of the clock of standby clock reference source so that network element switches to standby reference source.
(2) SSM information, this information are the SSM that has expanded among traditional SDH, as shown in Table 1 and Table 2, utilize the SSM coding of usefulness not to increase synchronous ethernet network element clock (that is SPC) rank,, it is encoded to 1100, the coding of SPC also can be except that 1100 other with the coding.Like this, SSM comprises PRC, SSU, SEC, SPC and DNU, and its priority orders is followed successively by PRC＞SSU＞SEC＞SPC＞DNU.Wherein, table 2 shows coding, the priority sequential scheduling of SSM information, and the SSM coding takies low 4 an of byte, high 4 reservations.
Table 2
The SSM coding Preferred sequence Credit rating is described Clock grade
0010 ↓ PRC 1 grade of reference clock
0100 ↓ SSU(A) 2 grades of nodal clocks
1000 ↓ SSU(B) 3E level clock
1011 ↓ SEC SDH equipment clock
1100 ↓ SPC Synchronous ethernet network element clock
1111 Minimum DNU Synchronizing signal is unavailable
Other - - Reserve
(3) PRI information, this information show the clock source priority of injection, can the manual static configuration.Be used for determining when the SSM in clock source rank is identical, to select the sequencing in clock source,, select the high clock source of priority (PRI) for referencial use according to the present invention.If the several reference sources in the network are PRC, then when its PRI information not simultaneously network to be in the principal and subordinate synchronous; Precedence information can dispose by following principle: its priority difference of each clock source of same clock quality in PSN (being that SSM is identical), that is, when the clock source of at least two identical clock qualities occurring among the PSN, their priority is set to difference.For example when losing the PRC reference source in the network, have other clock of several SSU (perhaps SEC) level, can configuration different PRI value in clock source be made network finally be synchronized to a timing reference input, and keep several standby clock reference sources.
(4) AM information, this information are the clock weight informations, it shows from root node, the summation of weights of clock chain circuit uplink of process, and link metric refers to the relevant information of link between two continuous network element ports of physical topology, link metric can calculate automatically, but also human configuration, it is mainly including, but not limited to following message: through the information such as clock performance of network element jumping figure, path, physical layer link information, the network element that connects.In order to realize conveniently, in the present invention to pass through the network element jumping figure as link metric.For example, AM information begins whenever just to add 1 through a network element from the clock chain circuit root node, it shows be exactly on the clock chain circuit prime network element jumping figure and.Certainly, can increase other factors, as clock performance of path, the network element that connects etc. as link metric.
Above-mentioned preparation has been arranged, just can realize technical scheme of the present invention, at first described method for synchronous of the present invention below with reference to Fig. 1.
Each network element in step 1, the PSN network calculates the weights of the link that links to each other with each port according to topological structure, and it is stored in each port status information.Described link metric is relevant with the characteristic of link, and for example relevant with the information such as clock performance of jumping figure, path, physical layer link information, the network element that connects, it can be finished by human configuration, also can calculate automatically.For convenience of calculation, be example only with the path jumping figure, also the link metric of each port of each network element all can be made as identical value (as 1).
Each network element in step 2, the PSN network transmits this information after initialization is finished in each port initialization ESSM information to the network element node port that topology links to each other.
During to the ESSM initialization of clock source access network element, the tracking mode of PM is made as effectively, configuration PRI information, SSM is set to the intrinsic information that carry in the clock source, and AM is set to the link metric that step 1 calculates.
During to the ESSM initialization of non-clock source access network element, the tracking mode of PM is set to effectively, and PRI is set to give tacit consent to particular value, SSM information is set to synchronous ethernet network element clock, that is, QL_SPC (its value can be 1100), AM is set to the link information that step 1 calculates.
Step 3, after each network element in the PSN network (access network element that comprises the clock source) receives ESSM, calculate the ESSM information (computational methods are referring to note 1) that makes new advances then, and the ESSM information of receiving by its each port of comparison every the scheduled time (as two clock cycle), choose the higher clock tracing of priority (ESSM priority decision rule is referring to note 2) according to ESSM priority decision rule, except tracked source side to network element will comprise new ESSM information bag send to other network element adjacent from its corresponding port with its topology, to tracked source side to network element send the ESSM bag that SSM information is DNU.
When the timing reference input in network is unstable, also can adopt following method to select timing reference input, after each port of network element (access network element that comprises the clock source) is received the ESSM bag, with this ESSM bag content compare with the timing reference input of this network element employing (decision rule of comparative approach ESSM priority is referring to note 1), if the priority of the timing reference input of this network element is greater than the priority in clock source in the ESSM information that receives, then abandon the ESSM bag of reception, otherwise, upgrade ESSM information, bag with the ESSM information upgraded except the direction in tracked source sends to other network element adjacent with its topology, to tracked source side to network element send the ESSM bag that SSM information is DNU.
Note 1, the new ESSM information criterion of calculating:
In the ESSM information that upstream network element is brought between AM information and upstream network element and this network element the weights of link carry out addition, produce the AM information in the new ESSM information.
The decision rule of note 2, ESSM priority is followed successively by: PM＞SSM＞PRI＞AM, as shown in Figure 2, describe the decision rule of ESSM priority in detail below with reference to Fig. 2.
Step 201, judge whether the tracing source state of PM in the ESSM information of a certain road is invalid, if then this ESSM priority is the highest, execution in step 202, otherwise promptly the tracing source state of PM is acquiescence particular value, execution in step 205.
Step 202, this moment this network element keep present tracking mode constant.
Whether the reference source information in step 203, the standby reference source information of judging PM and the ESSM information that all receive is consistent, if consistent, execution in step 204, otherwise, return step 203.
Step 204, the timing reference input of this network element is traced into standby reference source clock.
Step 205, judge whether only to exist one road clock, the priority of its SSM the highest (judgement of SSM and occupation mode are referring to note 3), if, execution in step 206, otherwise i.e. explanation has its SSM of two-way clock or multipath clock identical, and SSM priority is the highest, execution in step 207.
Step 206: then network element is selected this road clock tracing.
Step 207, from the highest two-way clock of the clock quality priority of step 205 or multipath clock, whether can select the highest clock of one road its PRI, if, execution in step 208, otherwise, i.e. explanation has its SSM, the PRI of two-way clock or multipath clock identical, and SSM, PRI priority are the highest, execution in step 209.
Step 208: then network element is selected the highest clock tracing of this road PRI.
If the SSM of the two-way clock of step 209 step 207 or multipath clock is identical with PRI, then from above-mentioned two-way or multipath clock, judge whether to have only the value minimum of the AM of one road clock again, if, execution in step 210, otherwise, execution in step 211,
Step 210, choose the minimum link clock of AM value and follow the tracks of.
Step 211, can select any clock to follow the tracks of, for example, select, select the less clock tracing of injection end slogan according to the port numbers of network element.
Illustrate: above rule only is to select a kind of method in clock source among the ESSM, also the content of ESSM information can be formed coding according to certain rule, selects clock source among the ESSM by the size of coding relatively.As, PM, SSM, PRI and AM are encoded sequentially, after network element is by the coding of receiving ESSM information, directly relatively should encode, also can determine the highest clock source of ESSM information medium priority that each port receives, select the highest clock tracing of priority then.
The judgement of note 3, SSM information and occupation mode:
● the clock quality hierarchal order is: PRC＞SSU＞SEC＞SPC＞DNU, when the Ethernet network element was selected tracing time clock source, the foundation that SSM judges was exactly this clock quality hierarchal order.
● under the normal tracking mode, network element sends its timing reference input of selecting for use downstream, upstream oppositely sends the credit rating information of DNU.
● lose the input clock reference source and do not have other available clock source that (during SSM＜=SPC), the network element clock will enter and keep or free-running operation, and downstream sends the SSM information of SPC clock grade at network element.
Since to tracked source side to the SSM information that sends of network element be the ESSM bag of DNU, even clock chain circuit is a net structure like this, can not form clock loop yet.
In order to find in time whether network element or link be normal, can be according to the testing mechanism of existing network, as OAM mechanism, detect network element or link and whether have fault, perhaps, each port is provided with a timer, the initial value of timer is made as scheduled time greater than step 3, when timer expiry, illustrate that there are fault in the link or the network element that link to each other with this port.In case when finding that adjacent network element or the link that links to each other with adjacent network element break down, will be made as SPC or DNU with the SSM of the ESSM information of network element that breaks down or link corresponding ports timely.
According to the present invention, behind netinit, all network elements that are connected with the clock source can spread ESSM information to network, after clock source access node receives this ESSM information, MAC Address, SSM and the PRI of source node are recorded in the timing reference input table of this node, after whole diffusion was finished, each network element that is connected with the clock source can write down the information in each clock source in the whole network like this.At this moment can be defined as standby reference source according to the clock source that priority is higher in the decision rule of ESSM priority and the timing reference input table, the standby reference source that each network element will be determined is arranged in the standby reference source information of PM.During the normal tracking of PSN network, can regularly communicate by letter between the network element of each clock source access point, transmission clock information, as the SSM and the PRI of each reference source, and the running status of access point network element, and definite standby clock reference source.
If the network element that is connected with the clock source in the current network is not received the clock reference source signal in special time (as two clock cycle), then can confirm the timing reference input fault, this network element this moment (network element that is connected with timing reference input) is to whole PSN network diffusion ESSM bag, the tracking mode of PM in the described ESSM bag is set to disarmed state, showing that the present clock reference source can not use, and in the standby clock source information of PM, be set to preferred standby clock source.All receive that the network element node of this bag can keep current lock-out state, up to having when specifying the identical ESSM bag that comprises the clock source of standby clock reference source to arrive with PM, this network element traces into the standby clock reference source (network element of inferior limit priority timing reference input) of this ESSM bag appointment.
If the network element that links to each other with the standby clock reference source (determining according to this network element internal timing reference input table) is not received the ESSM information of the network element transmission that the current network timing reference input is connected in special time, then can determine the network element that the current network timing reference input connects or all link occurs fault that are connected with this network element, the network element of preferential alternative reference source access point is to whole PSN network diffusion ESSM bag, the tracking mode of PM in the described ESSM bag is set to disarmed state, showing that the present clock reference source can not use, and in the standby clock source information of PM, be set to preferred standby clock source.All receive that the network element node of this bag can keep current lock-out state, and up to having when specifying the identical ESSM bag that comprises the clock source of standby clock reference source to arrive with PM, this network element traces into the standby clock reference source of this ESSM bag appointment.
When other link or network element failure took place, step 3 can guarantee automatic recovery.
In sum, when link or node broke down, the present invention can guarantee fault recovery, and the link protection when providing a plurality of clocks to lose efficacy simultaneously.
Embodiment one
Fig. 3 a-3e shows the assigning process that utilizes ESSM information to set up clock in Ethernet.Shown in Fig. 3 a-3e, various line style is represented the clock source information of different stage, wherein dotted line represent to have the ESSM of non-DNU information to transmit but and non-selected this clock source, oppositely the ESSM information that comprises the DNU signal that sends is not indicated.Suppose in this Ethernet that clock source network element node is that (as Fig. 3 a), the link metric between two continuous network element nodes is 1, and the ESSM rank of clock source network element node A is than node D height, as, SSM (A)＞SSM (D) for A and D
Perhaps SSM (A)=SSM (D) and PRI (A)＞PRI (D)
Whole network according to the rule in the step 3 relatively, after 1 end constantly (as Fig. 3 b), network element A selects stable track reference source: the clock source that links to each other with network element A, after 2 end constantly (as Fig. 3 c), network element B, C, D select stable track reference source: the clock source that links to each other with network element A, after 3 end constantly (as Fig. 3 d), network element E selects stable track reference source: the clock source that links to each other with network element A, after 4 end constantly (as Fig. 3 e), the timing reference input of each network element does not change, and draws stable time link at last.
Embodiment two
Fig. 4 a-4d shows the example that utilizes ESSM information to protect when the ethernet clock link occurs fault.The mistake that the stable back of clock distribution takes place is mainly caused by following 3 reasons: the link failure between timing reference input fault (comprising the root network element), network element failure and the network element, this example utilizes ESSM recovered clock link when only providing the timing reference input fault, shown in Fig. 4 a-4d, various line style is represented the clock source information of different stage, wherein dotted line represent to have the ESSM of non-DNU information to transmit but and non-selected this clock source, oppositely the ESSM information that comprises the DNU signal that sends is not indicated.Under normal tracking mode, shown in Fig. 4 a, all network elements are followed the tracks of the reference source that injects network element A according to the ESSM Information Selection, when the reference source that injects network element A breaks down, network element A can send an ESSM bag to whole PSN network, in this bag the tracking mode of PM be set to invalid, can not use to show this reference source, at this moment, the normally tracking mode of interior all network elements of network maintenance temporarily is constant, and (rule change of ESSM is still carried out in this process, but not as the judgment condition of selecting the source), when receiving the ESSM information that designated reference source (reference source of appointment coupling among the PM of clock information and ESSM) sends, just switch, whole network according to the rule in the step 3 relatively, after 1 end constantly (shown in Fig. 4 b), network element D follows the tracks of the reference clock that injects network element D according to the ESSM Information Selection, after 2 end constantly (shown in Fig. 4 c), and network element A, C, E selects to follow the tracks of the reference clock that injects network element D.After 3 end constantly (shown in Fig. 4 d), network element B selects to follow the tracks of the reference clock that injects network element D, thereby forms new stable clock tracking link.Method similarly during the multiple spot fault.
As shown in Figure 5, the invention also discloses a kind of network element, it can link to each other with the clock source, comprise: initialization unit, be used to calculate the weights of the link that links to each other with its each port, and the expansion Synchronization Status Message ESSM of this network element of initialization, described ESSM comprises protection information, clock quality, clock quality priority and clock weight information; Transmitting element is used for sending ESSM to the network element that links to each other with this network element; Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port; Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then; Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, be the ESSM of DNU to the network element tranmitting data register quality of the ESSM that sends described selected cell selection.
The invention also discloses a kind of network system, it comprises: clock source network element and common network element; Described clock source network element links to each other with common network element, described network element comprises: initialization unit, be used to calculate the weights of the link that links to each other with its each port, and the expansion Synchronization Status Message ESSM of this network element of initialization, described ESSM comprises protection information, clock quality, clock quality priority and clock weight information; Transmitting element is used for sending ESSM to coupled network element; Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port; Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then; Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, be the ESSM of DNU to the network element tranmitting data register quality of the ESSM that sends described selected cell selection.Described clock source network element also is provided with the timing reference input table, and described timing reference input table comprises: the clock quality priority in the MAC Address of the network element that links to each other with the clock source, the clock quality in clock source and clock source.
The present invention not only is suitable for Ethernet, also is applicable to ATM net and MPLS net, and described ESSM information can also other form (for example frame or expense etc.) transmit except the form with bag transmits.
According to the present invention, owing to comprised synchronous ethernet network element clock among the ESSM, make the ESSM bag be applicable to the clock stratum of PSN (as Ethernet), be convenient to select rational timing reference input and timing allocation.In addition,, can avoid clock loop at an easy rate or lock rudimentary clock problem owing to comprise the weights of the link of network in the ESSM information, and the link protection when providing a plurality of clocks to lose efficacy simultaneously.
Though described the present invention by embodiment, those of ordinary skills know, without departing from the spirit and substance in the present invention, just can make the present invention that many distortion and variation are arranged, and scope of the present invention is limited to the appended claims.

Claims (15)

1, a kind of method for synchronous is characterized in that, comprising:
The weights of the link that A, first each port of network element setting and its link to each other, and the expansion Synchronization Status Message ESSM of this network element of initialization, described ESSM comprises protection information, clock quality, clock quality priority and clock weight information;
B, described first network element send ESSM to the second coupled network element;
C, described second network element redefine the clock weight of new ESSM according to clock weight addition among the ESSM of the weights of the link of port and reception;
D, described second network element are selected the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that redefines, pre-defined rule is adjudicated for carrying out ESSM priority according to protection information, clock quality, clock quality priority and clock weight information successively, and the clock source among the ESSM that selects is set to the timing reference input of this network element; The ESSM that selects is issued the 3rd network element that links to each other with second network element, to the ESSM of the first network element tranmitting data register quality for forbidding DNU;
E, described the 3rd network element are according to clock weight addition among the ESSM of the weights of the link of port and reception, redefine the clock weight of new ESSM, described the 3rd network element is selected the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that redefines, pre-defined rule is adjudicated for carrying out ESSM priority according to protection information, clock quality, clock quality priority and clock weight information successively, and the clock source among the ESSM that selects is set to the timing reference input of this network element; The ESSM that selects is issued the 4th network element that links to each other with the 3rd network element, to the ESSM of the second network element tranmitting data register quality for forbidding DNU.
2, method for synchronous according to claim 1 is characterized in that, described step B specifically comprises: described first network element after the network element initialization or the scheduled time of being separated by send ESSM to coupled second network element.
3, method for synchronous according to claim 1 is characterized in that, described protection information comprises tracking mode and standby clock reference source.
4, method for synchronous according to claim 3 is characterized in that, the ESSM of described this network element of network element initialization specifically comprises:
When network element was clock source access network element, the tracking mode of protection information was set to effectively, and clock quality and clock quality priority are set to the clock quality and the clock quality priority of the reference source of clock;
When network element was non-clock source access network element, the tracking mode of protection information was set to effectively, and clock quality and clock quality priority are set to synchronous ethernet network element clock and priority arbitrarily.
5, method for synchronous according to claim 3 is characterized in that, the highest ESSM of its clock source priority of described selection specifically comprises:
If the tracing source state of protection information is invalid among a certain road ESSM that network element is received; then the timing reference input of this network element remains unchanged; when the clock source in the ESSM that is received is consistent with the standby clock reference source in the protection information; then select clock source among this ESSM as the timing reference input of this network element; otherwise, utilize clock quality, clock quality priority and clock weight information to select the clock source.
6, method for synchronous according to claim 5 is characterized in that, described clock quality, clock quality priority and the clock weight information of utilizing selects the clock source specifically to comprise:
S1, from the ESSM of all receptions, select the highest clock source of clock quality, if the highest clock source of clock quality is one, then select the timing reference input of this clock source as this network element, otherwise, execution in step S2,
S2, from the highest clock source of clock quality, select the highest clock source of clock quality priority,, then select the timing reference input of this clock source as this network element if the clock source of selecting is one, otherwise, execution in step S3,
Select the clock source of the weights minimum of link in S3, the clock source from step S2, selected, if the clock source of selecting is one, then select the timing reference input of this clock source as this network element, otherwise, the timing reference input of any one clock source selected as this network element.
7, according to one of them described method for synchronous of claim 1 to 6, it is characterized in that, described clock quality comprises source reference clock, first order synchronization supply unit, SDH equipment clock, synchronous ethernet network element clock and forbidding, and its priority orders is source reference clock＞first order synchronization supply unit＞SDH equipment clock＞synchronous ethernet network element clock＞forbidding.
8, according to one of them described method for synchronous of claim 1 to 6, it is characterized in that the described ESSM of redefining specifically comprises:
Among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port.
9, according to one of them described method for synchronous of claim 1 to 6, it is characterized in that, described method also comprises: be provided with the timing reference input table in the network element that the clock source links to each other, described timing reference input table comprises: the clock quality priority in the MAC Address of the network element that links to each other with the clock source, the clock quality in clock source and clock source.
10, method for synchronous according to claim 9, it is characterized in that described method also comprises: the network element that links to each other with the clock source determines according to the timing reference input table whether this network element is the network element that links to each other with timing reference input and the network element that links to each other with the standby clock reference source of present networks.
11, method for synchronous according to claim 10 is characterized in that, described method also comprises:
When network element is with timing reference input links to each other network element, if during NE Discovery timing reference input fault, then network element the tracking mode of the protection information of ESSM is made as invalid;
When network element is with the standby clock reference source links to each other network element, if NE Discovery is during with network element failure that timing reference input links to each other, then network element the tracking mode of the protection information of ESSM is made as invalid.
12, a kind of network element is characterized in that, comprising:
Initialization unit is used to calculate the weights of the link that links to each other with each port of this network element, and the expansion Synchronization Status Message ESSM of this network element of initialization, and described ESSM draws together protection information, clock quality, clock quality priority and clock weight information;
Transmitting element is used for sending ESSM to the network element that links to each other with this network element;
Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port;
Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then;
Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, to the network element tranmitting data register quality that sends the ESSM that described selected cell selects for forbidding the ESSM of DNU.
13, network element according to claim 12 is characterized in that, described network element can link to each other with the clock source.
14, a kind of network system, it comprises: clock source network element, it links to each other and common network element with the clock source, and it does not link to each other with the clock source; Described clock source network element links to each other with common network element, it is characterized in that described network element comprises:
Initialization unit is used to calculate the weights of the link that links to each other with its each port, and the expansion Synchronization Status Message ESSM of this network element of initialization, and described ESSM draws together protection information, clock quality, clock quality priority and clock weight information;
Transmitting element is used for sending ESSM to the network element that links to each other with this network element;
Receive generation unit, be used to receive the ESSM that other network element sends, and among the ESSM that each port is received the clock weight and send the network element of ESSM and this network element between the weights of link carry out the clock weight of the ESSM that addition receives as each port;
Selected cell is used for selecting the highest ESSM of its clock source priority according to pre-defined rule from the ESSM that receiving element receives, and the clock source among the ESSM is set to the timing reference input of this network element, starts the ESSM generation unit then;
Select transmitting element, be used to start transmitting element, except the network element that sends the ESSM that described selected cell selects sends the ESSM that regenerates with the network element that extroversion links to each other with this network element, to the network element tranmitting data register quality that sends the ESSM that described selected cell selects for forbidding the ESSM of DNU.
15, system according to claim 14, it is characterized in that, described network element also is provided with the timing reference input table, and described timing reference input table comprises: the clock quality priority in the MAC Address of the network element that links to each other with the clock source, the clock quality in clock source and clock source.
CNB2006100784175A 2006-05-24 2006-05-24 A kind of method for synchronous and system Expired - Fee Related CN100571115C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CNB2006100784175A CN100571115C (en) 2006-05-24 2006-05-24 A kind of method for synchronous and system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CNB2006100784175A CN100571115C (en) 2006-05-24 2006-05-24 A kind of method for synchronous and system

Publications (2)

Publication Number Publication Date
CN101043316A CN101043316A (en) 2007-09-26
CN100571115C true CN100571115C (en) 2009-12-16

Family

ID=38808553

Family Applications (1)

Application Number Title Priority Date Filing Date
CNB2006100784175A Expired - Fee Related CN100571115C (en) 2006-05-24 2006-05-24 A kind of method for synchronous and system

Country Status (1)

Country Link
CN (1) CN100571115C (en)

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101299749B (en) * 2007-04-30 2011-12-07 华为技术有限公司 Method and apparatus for transferring clock between networks
CN101399655B (en) * 2007-09-27 2011-04-20 华为技术有限公司 Determining method and apparatus for synchronization port of transparent clock device
CN101465707B (en) * 2008-12-15 2013-03-27 中兴通讯股份有限公司 Method and system for transferring protection time in synchronous network
CN101771661A (en) * 2008-12-29 2010-07-07 华为技术有限公司 Method, device and system for determining clock source
CN101931524A (en) * 2009-06-25 2010-12-29 中兴通讯股份有限公司 Clock source selecting method of synchronous digital hierarchy network
CN102130766B (en) * 2010-01-15 2013-12-04 华为技术有限公司 Method, equipment and system for synchronizing Ethernet clock tracking
CN102299937A (en) * 2010-06-28 2011-12-28 中兴通讯股份有限公司 Method and system for distributing clock server based on network
CN101986595A (en) * 2010-11-01 2011-03-16 中兴通讯股份有限公司 Time synchronization method and nodes
CN102185687B (en) * 2011-05-18 2015-04-01 中兴通讯股份有限公司 System and method for realizing clock synchronization among different units
WO2011144066A2 (en) * 2011-05-23 2011-11-24 华为技术有限公司 Method and device for clock synchronization
CN102368696B (en) * 2011-09-14 2014-07-30 杭州华三通信技术有限公司 Method for selecting synchronous clock source and apparatus thereof
CN102946290B (en) * 2012-11-01 2015-05-27 华为技术有限公司 Clock information processing method and device
CN105099647A (en) * 2014-05-16 2015-11-25 中兴通讯股份有限公司 Synchronous method, controller, synchronous node and synchronous network
EP3289814B1 (en) * 2015-04-30 2019-11-13 Telefonaktiebolaget LM Ericsson (publ) Methods used in radio nodes and associated radio nodes
CN106302251B (en) * 2015-06-26 2019-09-06 深圳市中兴微电子技术有限公司 A kind of exchange network synchronous method and switch, access device
CN106712923B (en) * 2015-11-12 2020-06-23 中国移动通信集团公司 Synchronous network recovery method and device
CN106789139B (en) * 2015-11-24 2020-05-05 大唐移动通信设备有限公司 Multipoint fault processing method and device
CN106921509B (en) * 2015-12-28 2020-07-10 中兴通讯股份有限公司 Method and device for synchronous management of whole network clock
CN110832805B (en) 2017-12-18 2021-06-29 华为技术有限公司 Method for synchronizing network equipment and network equipment
CN116801291A (en) * 2022-03-14 2023-09-22 华为技术有限公司 Clock state synchronization method and communication device
CN115102660B (en) * 2022-08-26 2022-11-04 深圳市英特瑞半导体科技有限公司 Method, device, equipment and storage medium for breaking based on synchronous Ethernet

Also Published As

Publication number Publication date
CN101043316A (en) 2007-09-26

Similar Documents

Publication Publication Date Title
CN100571115C (en) A kind of method for synchronous and system
CN103916950B (en) Method for synchronizing time and system
CN103107876B (en) A kind of method and system and device of multi-clock simultaneous techniques mixed networking
EP2144400B1 (en) Distributed ethernet system and method for detecting fault based thereon
CN101286835B (en) Clock tracing method, device and network element device
US3519750A (en) Synchronous digital multiplex communication system including switchover
CN1744479B (en) Method of setting up a backup path in a transport network and network element for transmission network
CN103873224B (en) Construction method for high-precision time synchronization system based on IP (internet protocol) network
CN102006135A (en) Method and device for selecting synchronous clock source
JPH11127128A (en) Synchronizing device
CN101183982A (en) Automatic discovery method based on topological structure of multi-service transmission looped network
CN101729371A (en) Method for service transmission and device for service transmission
CN100571114C (en) A kind of synchronised clock providing device and implementation method
CN103532231B (en) Intelligent power distribution network IEEE1588 timing synchronization system on basis of industrial Ethernet direct connection access rings
US6567422B1 (en) Network synchronization controller and timing loop prevention method
CN100461735C (en) Path selecting method based on AOMDV protocol in wireless sensor network
US5706291A (en) Method and apparatus for connecting two messaging systems having differing synchronizations one of which is message-based
CN1274117C (en) Method of preventing formation of timing loop in synchronous network
CN102420688A (en) Clock frequency synchronization method and device
CN101141240B (en) SDH clock automatically networking method
Kim et al. Cluster-based hierarchical time synchronization for multi-hop wireless sensor networks
CN102386991B (en) Timeslot interchange operating method for time division multiple address access system in wireless mobile self-organized network
CN102572907A (en) Wireless communication mode of industrial information corridor
CN101771488B (en) Method, system and equipment for improving reliability of multi-service transport network
CN101515832A (en) Method and device for generating multipath system clock

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20091216

Termination date: 20160524

CF01 Termination of patent right due to non-payment of annual fee