CN101227381B - Method for packet switching network to transmit clock synchronizing information and circuit simulation communication equipment - Google Patents
Method for packet switching network to transmit clock synchronizing information and circuit simulation communication equipment Download PDFInfo
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- CN101227381B CN101227381B CN2007100007778A CN200710000777A CN101227381B CN 101227381 B CN101227381 B CN 101227381B CN 2007100007778 A CN2007100007778 A CN 2007100007778A CN 200710000777 A CN200710000777 A CN 200710000777A CN 101227381 B CN101227381 B CN 101227381B
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Abstract
The invention discloses a method for transferring synchronous information by a packet switching network, and the packet switching network comprises at least two network segments, and the method comprises utilizing a communicating node to connect a first PSN network segment and a second PSN network segment which are adjacent, getting clock synchronous information from the first PSN network segment on the communicating node according to a first synchronous clock mode, and transferring the clock synchronous information which is obtained to the second PSN network segment according to a second synchronous clock mode. The invention does circuit simulation in a packet switching network in segments, which makes full use of synchronous clock source of the packet switching network to carry on relatively reliable common clock type circuit simulation or difference recovery time type circuit simulation, the invention can reduce artificial spanned network segment of self-adapting recovery clock type circuit, and can greatly improve the precision and stability of a recovery clock. The invention also discloses simulation equipment of a packet switching network circuit, which is beneficial for grading to carry on the specific implementation of circuit simulation in a packet switching network.
Description
Technical field
The present invention relates to PSN (Packet Switched Network, packet switching network) technology, the circuit simulation communication equipment that relates in particular to the method for PSN network to transmit clock synchronizing information and use this method.
Background technology
At present, high bandwidth, Ethernet is that the packet switching network of representative has been applied in the metropolitan area network cheaply, can merge voice, video and data communication; Simultaneously, historical long-range TDM (Time DivisionMultiplex, time division multiplexing) equipment has had application widely.How to utilize packet switching network technology to connect TDM equipment and network, be metropolitan area network provider become before the complete service provider the problem that will face.
CESoPSN (Circuit Emulation Services over Packet Switched Network; The packet switching network circuit emulation service) basic thought is on the PSN network, to build a passage; Transmit TDM circuit or other constant speed transmission circuit therein; Like the communication data of synchronous serial ports etc., thereby make the TDM equipment of the arbitrary end of network needn't be concerned about whether its network that connects is a TDM network.The PSN network is used to the behavior of emulation TDM circuit, so be called circuit simulation.
The network configuration of CESoPSN can be as shown in Figure 1; TDM equipment 111 is connected IWF (Interworking Function through the TDM interface respectively with 112; Mutual linkage function) equipment 121 and 122 carries out transmitted in packets through the PSN network between the IWF equipment 121 and 122.IWF inserts the equipment of PSN as TDM equipment; Comprise TDM interface and PSN interface; Convert the tdm data of needs transmission to a series of groupings; And through the PSN Network Transmission to the opposite end IWF equipment, this series of packets of IWF equipment utilization of opposite end regenerates tdm data again, thereby realizes the communication of two ends TDM equipment.
Some time deviations be possibly have during the IWF equipment of all packet arrives network exits, packetization delay deviation or packet jitter are referred to as.Because the TDM circuit has invariable bit rate, the output that is grouped in that therefore must will comparatively fast arrive cushions before, so just can compensate and other delay inequality between dividing into groups more slowly, and the sort buffer device is called wobble buffer.
Clock synchronization is any Circuit-switched key technology that realizes through dividing into groups.Each of transmission all must be exported from packet network by its same speed that gets into packet network, otherwise the wobble buffer of destination node will be filled or be cleared.Only if therefore exist a kind of method to come to distribute common clock, otherwise the clock restore funcitons must be arranged, in order to avoid destroy the integrality of data to two ends.
For example, connecting through the TDM emulation link on operator's packet network between two clients, to recipient's client, the frequency f that TDM is professional
ServiceMust accurately regenerate in the exit of packet network.If the frequency of transmit leg and recipient's client does not match for a long time, will cause the packet network exit to form waiting list, if the clock that regenerates than former clock slowly then buffer be filled, otherwise then can be cleared.Both of these case all can cause loss of data and service quality to descend.
In the prior art, adopting following three kinds of modes to carry out clock synchronization usually, is the example explanation with network configuration shown in Figure 1 still:
Common synchronised clock mode: first kind of realization of common synchronised clock mode is as shown in Figure 2, and TDM equipment 111 and 112 inserts Synchronization Network, obtains synchronised clock from Synchronization Network; Is example with TDM equipment 111 as transmit leg; IWF equipment 121 receives tdm data from the receiving lines that connects TDM equipment 111; Be converted into a series of groupings and give IWF equipment 122, extract clock as its clock that sends to TDM equipment 111 from this receiving lines simultaneously through the PSN network delivery; IWF equipment 122 is also like this.IWF equipment 122 is consistent with the transmission rate of TDM equipment 111 toward the transmission rate of TDM equipment 112 like this, and the situation that is filled or is cleared can not appear in the wobble buffer of IWF equipment 122.
Second kind of realization of common synchronised clock mode is as shown in Figure 3, and IWF equipment 121 and 122 inserts Synchronization Network, obtains synchronised clock from Synchronization Network; TDM equipment 111 extracts clock as the clock that sends to IWF equipment 121 from the receiving lines that connects IWF equipment 121; TDM equipment 112 is also like this.It is thus clear that; The synchronised clock that relies on Synchronization Network to provide; Need not pass through PSN packet delivery synchronizing information, the receive clock frequency of TDM equipment 112 is identical with the tranmitting data register frequency of TDM equipment 111, and the receive clock frequency of the TDM equipment 111 also tranmitting data register frequency with TDM equipment 112 is identical.
Difference is recovered the synchronised clock mode: IWF equipment 121 and 122 inserts a Synchronization Network, obtains common synchronised clock f
n, the tranmitting data register of TDM equipment and f
nAsynchronous.Is example with TDM equipment 111 as transmit leg, and its realization is as shown in Figure 4, and the IWF equipment 121 that is connected with transmit leg TDM equipment 111 is main IWF, and the IWF equipment 122 of opposite end is from IWF.Main IWF receives tdm data and converts a series of circuit simulations into from the TDM receiving lines and divides into groups, and gives IWF equipment 122 through the PSN network delivery, and main simultaneously IWF extracts the tranmitting data register f of TDM equipment 111 from this receiving lines
Service, compare f
ServiceAnd f
nDifference on the frequency, and differential information is delivered to from IWF through packet package.This packet package can be that the circuit simulation that carries clock frequency differential information and tdm data divides into groups, and also can be the grouping of independently only carrying the clock frequency differential information.From IWF according to frequency difference information and f
nClock recovery goes out the tranmitting data register f of TDM equipment 111
Service, as the clock that sends to TDM equipment 112.IWF equipment 122 is consistent with the transmission rate of TDM equipment 111 toward the transmission rate of TDM equipment 112 like this, and the situation that is filled or is cleared can not appear in the wobble buffer of IWF equipment 122.
Adopt difference to recover between two TDM devices communicatings of synchronised clock mode in the reality, the clock transmission can be unidirectional, also can be two-way.
During the clock unidirectional delivery: the TDM equipment of an end is called main TDM equipment, and the other end is called the equipment from TDM; Main TDM equipment adopts business clock f
ServiceAs the tranmitting data register of TDM interface, its business clock f
ServiceIt can be local clock or from the synchronised clock of certain Synchronization Network; Adopt TDM receiving lines clock recovered f from TDM equipment
ServiceAs its TDM tranmitting data register.The IWF equipment that is connected with main TDM equipment is main IWF, is from IWF with the IWF equipment that is connected from TDM equipment; The business clock f of main IWF to recover from the TDM receiving lines
ServiceAs the TDM tranmitting data register, simultaneously with Network Synchronization clock f
nWith business clock f
ServiceDifferential information give from IWF but the packet recovery clock that does not receive from the PSN network through packet delivery; Go out business clock f from IWF according to difference modes and the PSN packet recovery that receives
Service, as its TDM tranmitting data register, but not with business clock f
ServiceWith Network Synchronization clock f
nDifferential information pass to main IWF.
During the clock bi-directional: the TDM equipment at two ends all adopts business clock f separately
ServiceAs the tranmitting data register of TDM interface, its business clock can be respectively a local clock or from the synchronised clock of the Synchronization Network that connects separately; The IWF at two ends all need recover the transmission business clock f of local terminal TDM equipment from the TDM receiving lines
Service, and will send business clock f
ServiceWith Network Synchronization clock f
nDifferential information through packet delivery to opposite end IWF.The IWF at two ends all need go out the transmission business clock f of opposite end TDM equipment from the PSN packet recovery
ServiceGive the TDM tranmitting data register of local terminal TDM equipment as it.
Thus it is clear that, the PSN Network Synchronization clock f that relies on Synchronization Network to provide
nWith the difference pass-algorithm of two ends IWF equipment, the TDM equipment at two ends can be with identical transmitting-receiving frequency collaborative work.
Self-adaptive recovery synchronised clock mode: this mode is without any need for external synchronization source.Is example with TDM equipment 111 as transmit leg, and its realization sees also Fig. 5, and the IWF equipment 121 that is connected with transmit leg TDM equipment 111 is main IWF, and the IWF equipment 122 of opposite end is from IWF.Main IWF is encapsulated as packet package through the PSN Network Transmission with tdm data, but does not transmit the tranmitting data register f of TDM equipment 111
ServiceInformation.Infer former tranmitting data register frequency f from IWF according to the packet arrives speed that changes
Service, this process is called adaptive clock recovery.IWF equipment 122 is consistent with the transmission rate of TDM equipment 111 toward the transmission rate of TDM equipment 112 like this, and the situation that is filled or is cleared can not appear in the wobble buffer of IWF equipment 122.
As adopting difference to recover the synchronised clock mode, to adopt between two TDM devices communicatings of self-adaptive recovery synchronised clock mode, the clock transmission can be unidirectional, also can be two-way; Its operation principle is similar with employing difference recovery synchronised clock mode.
It is thus clear that, the IWF apparatus self-adaptation pass-algorithm at support two ends, the TDM equipment at two ends can be with identical transmitting-receiving frequency collaborative work.
Common synchronised clock mode and difference recovered clock mode have common external synchronization source, thereby can realize quite accurate clock synchronization.To self-adaptive recovery synchronised clock mode; When recovered clock, must consider some fundamental characteristics of PSN network; Comprise packet loss, grouping repetition, grouping rearrangement and packetization delay deviation etc.; The particularly distribution of packetization delay, heterogeneous networks formation, different forwarding mechanism, various network equipment QoS (Quality of Service, service quality) configuration, different bag length, distinct interface bandwidth availability ratio etc. all possibly influence the distribution of packetization delay.These characteristics can influence shake and the drift index that the self-adaptive recovery algorithm recovers clock.The characteristic possibility difference of different PSN networks is bigger, and the characteristic of identical PSN network also possibly bigger variation take place with its load change.Sometimes a self-adaptive recovery algorithm can recover accurate clock on a PSN network, changed network configuration to another one PSN network or same PSN network after, just possibly can't operate as normal.
In practical application; TDM equipment through the CESoPSN interconnection possibly crossed over far distance; Be difficult in two ends and obtain common external clock reference; When adopting self-adaptive recovery synchronised clock mode,, be difficult to recover accurately and stable clock at the self-adaptive recovery end of PSN network again because PSN network therebetween often comprises the PSN network segment that a plurality of characteristics are different.
Summary of the invention
The present invention will solve is the accuracy of clock synchronization when communicating pair is crossed over a plurality of PSN network segment and the problem of poor stability.
In the method for PSN network to transmit clock synchronizing information of the present invention, said packet switching network comprises at least 2 network segments, connects adjacent a PSN network segment and the 2nd PSN network segment by communication node, and said method comprises:
On communication node, obtain clock synchronization information from a PSN network segment according to the first synchronised clock mode;
The clock synchronization information that obtains is transmitted to the 2nd PSN network segment according to the second synchronised clock mode.
Preferably, said clock synchronization information is the clock synchronization information of packet switching network circuit emulation service CESoPSN.
Preferably, the said first synchronised clock mode or the second synchronised clock mode comprise common synchronised clock mode, difference recovery synchronised clock mode or self-adaptive recovery synchronised clock mode.
Preferably, when the first or second synchronised clock mode was common synchronised clock mode or difference recovery synchronised clock mode, said method also comprised: on communication node, receive the external clock reference that is used for carrying out clock synchronization.
Alternatively, said communication node comprises first mutual linkage function IWF equipment and the 2nd IWF equipment;
A said IWF equipment connects a PSN network segment with the PSN interface, obtains clock synchronization information according to the first synchronised clock mode, and this clock synchronization information is passed to the 2nd IWF equipment;
Said the 2nd IWF equipment connects the 2nd PSN network segment with the PSN interface, transmits the clock synchronization information that an IWF equipment provides according to the second synchronised clock mode to the 2nd PSN network segment.
Preferably, said IWF equipment and the 2nd IWF equipment have the time division multiplexing tdm interface respectively, and first passes through the TDM interface transmits clock synchronization information and tdm data to the 2nd IWF equipment.
Preferably, said communication node is a communication equipment, and said communication equipment connects a PSN network segment and the 2nd PSN network segment respectively with two PSN interfaces, and the grouping that a PSN network segment is forwarded to the 2nd PSN network segment is directly transmitted with the circuit simulation packet format.
The present invention provides a kind of circuit simulation communication equipment of packet switching network, comprises the PSN interface and the 2nd PSN interface, processing unit, first clock unit and the second clock unit that connect a PSN network segment and the 2nd PSN network segment respectively, wherein:
First clock unit obtains clock synchronization information according to the control of processing unit from a PSN network segment; Export clock recovered to the second clock unit, and feed back the grouping tranmitting data register information of a PSN interface to processing unit according to the clock synchronization information that receives from the second clock unit;
The second clock unit obtains clock synchronization information according to the control of processing unit from the 2nd PSN network segment; Export clock recovered to first clock unit, and feed back the grouping tranmitting data register information of the 2nd PSN interface to processing unit according to the clock synchronization information that receives from first clock unit;
The form that processing unit directly divides into groups with circuit simulation between first and second PSN interface is transmitted and is divided into groups; Comprise according to the grouping tranmitting data register information of a PSN interface of first clock unit feedback and dividing into groups, and the grouping tranmitting data register information of the 2nd PSN interface that feeds back according to the second clock unit is divided into groups to the 2nd PSN network segment transtation mission circuit emulation to a PSN network segment transtation mission circuit emulation.
Preferably, said first clock unit feeds back the grouping tranmitting data register information of a PSN interface according to the synchronised clock acquisition clock synchronization information that receives from first external clock reference and/or to processing unit;
Said second clock unit feeds back the grouping tranmitting data register information of the 2nd PSN interface according to the synchronised clock acquisition clock synchronization information that receives from second external clock reference and/or to processing unit.
Preferably, said communication equipment also comprises the TDM interface, is used for external TDM equipment;
The clock that said processing unit provides according to first clock unit or second clock unit carry out TDM interface and a PSN interface or and the 2nd PSN interface between Data Format Transform.
Alternatively, a said PSN interface and the 2nd PSN interface are two logic interfacings of same physical port.
The packet switching network that the needs that will connect two ends TDM equipment among the present invention carry out clock synchronization is divided into the PSN network segment of the identical or different synchronised clock mode of a plurality of employings; Elder generation recovers clock synchronization information according to the synchronised clock mode of the last PSN network segment on the communication node that connects adjacent two PSN network segments, transmits clock synchronization information according to the clock synchronization mode of next PSN network segment to this PSN network segment again.The present invention carries out the clock synchronization segmentation; Can make full use of the synchronised clock source of two TDM communication between devices links; Can the network that does not have the synchronised clock source be carried out having improved the accuracy of clock synchronization, and can having realized good stable property synchronously according to its characteristic segmentation simultaneously.
Description of drawings
Fig. 1 is the schematic network structure of CESoPSN in the prior art;
Fig. 2 is first kind of realization sketch map of common synchronised clock mode in the prior art;
Fig. 3 is second kind of realization sketch map of common synchronised clock mode in the prior art;
Fig. 4 is the realization example figure that difference is recovered the synchronised clock mode in the prior art;
Fig. 5 is the realization example figure of self-adaptive recovery synchronised clock mode in the prior art;
Fig. 6 is an Application of C ESoPSN network configuration exemplary plot of the present invention;
Fig. 7 is the structural representation of CESoPSN IWF equipment in the prior art;
Fig. 8 is a kind of structural representation of communication node among Fig. 6;
Fig. 9 is the structural representation of communication node according to the invention.
Embodiment
The common layered configuration of the packet switching network is divided into the local network of users, Access Layer, convergence-level and core layer etc.In the general difficult synchronised clock source that obtains of the local network of users of network edge, some access layer networks can provide the synchronised clock source, then become more readily available the synchronised clock source or are easy to build Synchronization Network in convergence-level, core layer.
To two TDM equipment of crossing over remote through the CESoPSN interconnection; Although the two ends at CESoPSN can not obtain the synchronised clock source; But in its communication link, then there is part possibly have the synchronised clock source; Therefore can consider to adopt common synchronised clock mode or difference to recover the synchronised clock mode, realize CESoPSN and needn't adopt self-adaptive recovery synchronised clock mode to cross over whole PSN network at subnetwork with synchronised clock source; In addition; To not having the subnetwork in synchronised clock source; Also can adopt the further segmentation of different adaptive algorithms to carry out circuit simulation respectively, can adopt different self-adaptive recovery algorithms with pure Ethernet switch environment like router environment according to its network characteristic.Realize above-mentioned 2 points, the clock synchronization of circuit emulation service can be carried out in segmentation in the packet switching network.
The applied a kind of exemplary CESoPSN network configuration of the present invention is as shown in Figure 6, and TDM equipment 111 is connected IWF equipment 121 and 122 respectively with 112, carries out transmitted in packets through the PSN network between the IWF equipment 121 and 122; The PSN network is divided into three sections, and IWF equipment 121 inserts the PSN network segment 310, and communication node 210 couples together the PSN network segment 310 and 320, and communication node 220 couples together the PSN network segment 320 and 330, and IWF equipment 122 inserts the PSN network segment 330.
Is example with TDM equipment 111 as transmit leg, and it is that circuit simulation divides into groups that IWF equipment 121 sends data transaction with TDM, transfers to communication node 210 through the PSN network segment 310; Communication node 210 is from the PSN network segment 310 receive clock synchronizing informations and/or circuit simulation divides into groups and recover the corresponding TDM tranmitting data register of above-mentioned grouping according to the synchronised clock mode that the PSN network segment 310 adopts, and the synchronised clock mode that adopts according to the PSN network segment 320 again will recover clock information and/or circuit simulation divides into groups to pass to communication node 220 through the PSN network segment 320; Similar with communication node 210; The clock synchronization mode conversion that the clock synchronization mode that communication node 220 pairs of above-mentioned groupings carrying out PSN network segment 320 adopts and the PSN network segment 330 adopt; And clock synchronization information and/or circuit simulation divided into groups to be delivered to the PSN network segment 330 from the PSN network segment 320, and transmit it to IWF equipment 122 through the PSN network segment 330.The content that IWF equipment 122 divides into groups circuit simulation is reduced to the data of TDM form, and the synchronised clock mode according to the PSN network segment 330 recovers corresponding TDM tranmitting data register simultaneously, according to the clock frequency that recovers tdm data is sent to TDM equipment 112.
The PSN network segment 310,320 can adopt identical or different clock synchronization mode with 330, its division can by the user according to the characteristic of the acquisition in identical synchronised clock source, each network, the combined factors such as position that can carry out the communication node place that the synchronised clock mode changes consider to confirm.Need to prove that clock synchronizing method of the present invention is that example describes with CESoPSN, but any those skilled in the art can understand all, the method for the invention can be applied to other business that need carry out clock synchronization equally.
To connecting the communication node of two PSN network segments in the PSN network, be without loss of generality, suppose that the grouping that need carry out clock synchronization in the PSN network is forwarded to the 2nd PSN network segment of its connection by the PSN network segment that this communication node connected; The one PSN network segment adopts the first synchronised clock mode, and the 2nd PSN network segment adopts the second synchronised clock mode, and clock synchronizing method then according to the invention can have following flow process on communication node:
On communication node with the first synchronised clock mode from a PSN network segment recovered clock synchronizing information;
On this communication node, the clock synchronization information that recovers is passed to the 2nd PSN network segment according to the second synchronised clock mode.
According to the difference of each PSN clock synchronization mode that the network segment adopts, communication node receives and to the packet package that the 2nd PSN network segment sends, has specific fields from a PSN network segment and comprises clock synchronization information, also possibly not have such field.The situation that does not comprise clock synchronization information for packet package; Because packet package is to arrive communication node according to the synchronised clock mode that a PSN network segment is adopted; Perhaps send according to the second synchronised clock mode, need the clock synchronization information that transmits so packet package itself has impliedly been carried by communication node.
The first and second synchronised clock modes can be identical, also can be different.When the first and second PSN network segments adopt identical synchronised clock mode, can adopt different synchronization algorithm or different synchronization clock source.When the first synchronised clock mode need be utilized the synchronised clock source, should receive external clock reference through before the first synchronised clock mode recovered clock synchronizing information at communication node; When the second synchronised clock mode need be utilized the synchronised clock source,, communication node should receive external clock reference equally before transmitting clock synchronization information by the second clock method of synchronization.
To CESoPSN, the first synchronised clock mode can be that common synchronised clock mode, difference are recovered synchronised clock mode or self-adaptive recovery synchronised clock mode, and the second synchronised clock mode also can be above-mentioned three kinds of synchronised clock modes.
Need to prove that if in Fig. 6, use said method on the communication node 210, IWF equipment 121 is sent to the grouping of IWF 122, a PSN network segment is that the PSN network segment 310, the two PSN network segments are the PSN network segment 320; IWF equipment 122 is sent to the grouping of IWF equipment 121, and a PSN network segment is that the PSN network segment 320, the two PSN network segments are the PSN network segment 310.
Below be base description several kinds of applying examples of the present invention with CESoPSN network configuration shown in Figure 6.
In the applying examples one, IWF equipment 121 can be connected to same Synchronization Network with communication node 210, and communication node 220, IWF equipment 122 then can't obtain external sync clock source, and the PSN network segment 320 has different characteristic with the PSN network segment 330.Divide into groups for the CESoPSN that sends to IWF equipment 122 from IWF equipment 121; Can between IWF equipment 121 and communication node 210, adopt common synchronised clock mode; Adopting self adaptation synchronised clock mode between communication node 210 and 220, between communication node 220 and the IWF equipment 122, and the adaptive algorithm between the communication node 210 and 220, between communication node 220 and the IWF equipment 122 is different; Divide into groups for the CESoPSN that sends to IWF equipment 121 from IWF equipment 122; Self adaptation synchronised clock mode can adopted between IWF equipment 122 and the communication node 220, between the communication node 220 and 210; Between communication node 210 and IWF equipment 121, adopt common synchronised clock mode, and the adaptive algorithm between IWF equipment 122 and the communication node 220, between the communication node 220 and 210 is different.
In the applying examples two, IWF equipment 121 with can be connected to same Synchronization Network A with communication node 210, communication node 210 can be connected to another Synchronization Network B with communication node 220, IWF equipment 122 can't obtain external sync clock source.Divide into groups for the CESoPSN that sends to IWF equipment 122 from IWF equipment 121; Can between IWF equipment 121 and communication node 210, adopt common synchronised clock mode with the clock source of Synchronization Network A; Between communication node 210 and 220, adopt difference to recover the synchronised clock mode, between communication node 220 and IWF equipment 122, adopt self adaptation synchronised clock mode with the clock source of Synchronization Network B; Divide into groups for the CESoPSN that sends to IWF equipment 121 from IWF equipment 122; Can between IWF equipment 122 and communication node 220, adopt self adaptation synchronised clock mode; Between communication node 220 and 210, adopt difference to recover the synchronised clock mode; Between communication node 210 and IWF equipment 121, adopt common synchronised clock mode, and the synchronised clock mode between communication node 220 and 210, between communication node 210 and the IWF equipment 121 has different external clock source.
In some application scenarios, the communication node that has synchronised clock mode translation function among the present invention can be through forming two IWF series connection of the prior art.
IWF of the prior art has structure shown in Figure 7 usually, and processing unit 720 connects TDM interface 710, PSN interface 730, bag buffer unit 740 and clock unit 750 respectively; TDM interface 710 is connected with clock unit 750, and clock unit 750 can receive the synchronised clock of external clock reference.IWF equipment can comprise a plurality of TDM interfaces 710 and/or PSN interface 730.
Particularly, processing unit 720 can be according to the speed transmitting-receiving tdm data of TDM interface 710 send-receive clocks; Can handle the PSN that receives from PSN interface 730 and divide into groups, and PSN divide into groups lose, repeat, sort; When adopting the difference reset mode, can control clock unit 750 according to difference on the frequency and recover the clock that receives the correspondence of dividing into groups; When adopting the self-adaptive recovery mode, can recover according to the adaptive algorithm control clock unit 750 of its operation and receive the corresponding clock that divides into groups.When adopting common synchronised clock mode, difference recovery synchronised clock mode or self adaptation synchronised clock mode, processing unit 720 can also have rhythm to send the PSN grouping according to the PSN tranmitting data register from clock unit 750; When adopting difference to recover the synchronised clock mode, processing unit 720 can also transmit the clock difference information in PSN divides into groups.
Particularly, clock unit 750 can be from TDM interface recovered clock; Can receive external sync clock source from Synchronization Network; Can be relatively from the clock of TDM interface circuit and from the difference on the frequency between the common clock source of Synchronization Network.When adopting common synchronised clock mode, difference recovery synchronised clock mode and self adaptation synchronised clock mode, clock unit 750 can recover the corresponding clock of PSN grouping according to the setting of processing unit 720.Clock unit provides the clock that recovers out from the PSN network segment as the TDM tranmitting data register can also for TDM interface 710.
As previously mentioned, the communication node that has synchronised clock mode translation function among the present invention can be formed by two IWF equipment serial connections shown in Figure 7, is example with the communication node among Fig. 6 210, and its structure can be as shown in Figure 8.For simplicity, each the IWF equipment among Fig. 8 has only been represented its PSN interface and TDM interface.
To be grouped into example through the CESoPSN that communication node 210 sends to IWF equipment 122 from IWF equipment 121; Recover clock synchronization information the circuit simulation that IWF equipment 810 receives from the PSN network segment divides into groups, this information of clock synchronization is passed to IWF equipment 820 through the physical circuit between the TDM interface of IWF equipment 810 and 820; IWF equipment 820 will be passed to the PSN network segment 320 from the clock synchronization information of IWF equipment 810.Certainly, IWF equipment 810 also can be transferred to the tdm data of circuit simulation packet bearer IWF equipment 820, will be carried in the PSN grouping by IWF equipment 820 and send to the PSN network segment 320.
The invention provides a kind of communication equipment, can be as communication node with synchronised clock mode translation function.This communication equipment can have structure shown in Figure 9, and processing unit 920 connects bag buffer unit 740, a PSN interface 930, the 2nd PSN interface 950, first clock unit 960 and second clock unit 970 respectively; First clock unit 960 is connected with second clock unit 970.If communication equipment need be provided to the connection of TDM equipment, can also increase TDM interface 710, be connected with second clock unit 970 with processing unit 920, first clock unit 960 respectively.
The one PSN interface 930 connects a PSN network segment of the first synchronised clock mode of employing, and the 2nd PSN interface connects the 2nd PSN network segment of the second synchronised clock mode of employing.
The synchronised clock of first external clock reference and second external clock reference can be identical, also can be different.First clock unit 960 can be realized respectively by two unit with second clock unit 970, also can be realized by the clock module that two clock unit functions can be provided.
Circuit simulation to receive and will be sent to the 2nd PSN network segment from a PSN network segment divides into groups; Processing unit 920 instructions first clock unit 960 recovers the clock synchronization information of a PSN network segment, and this clock synchronization information is exported to second clock unit 970 by first clock unit 960; Second clock unit 970 is the tranmitting data register that processing unit 920 provides the 2nd PSN interface 950 according to the clock synchronization information that recovers; When processing unit 920 sends at the tranmitting data register that provides according to second clock unit 970, will be passed to the 2nd PSN network segment from the clock synchronization information that a PSN network segment obtains.Circuit simulation to receive and will be sent to a PSN network segment from the 2nd PSN network segment divides into groups, and the processing procedure of processing unit 920 and above-mentioned similar no longer repeats.
Need to prove; The forwarding that circuit simulation is grouped between a PSN network segment and the 2nd PSN network segment on the communication equipment according to the invention need not passed through this process: the circuit simulation packet switched is the TDM form; Then mutual through the TDM circuit, and be that circuit simulation divides into groups by the TDM format conversion further; Divide into groups but under the control of processing unit 920, read the circuit simulation that receives from a PSN interface; Can change the content of grouping if needed; Need increase during like the difference method of synchronization or revise the field that comprises the clock difference information; But can not change the form of grouping, the form that directly divides into groups with circuit simulation sends from another PSN interface.
In addition, a PSN interface and the 2nd PSN interface can be two physical ports; Also can be two logic interfacings of same physical port.
To sum up; The present invention makes full use of the network segment that the packet switching network has the synchronised clock source and carries out synchronously common or difference is recovered synchronously; Can farthest reduce the network segment that self-adaptive recovery synchronised clock mode is crossed over, can guarantee that recovered clock has better index and stability; Even to obtaining the network segment in synchronised clock source, the present invention also can be limited in the essentially identical network segment of characteristic with self-adaptive recovery synchronised clock mode,, can improve the precision and the stability of recovered clock equally greatly through guaranteeing the precision of each network segment.
The communication equipment with synchronised clock mode translation function that the present invention proposes can be realized the cascade of two kinds of synchronised clock modes between two PSN interfaces of an equipment, simplify the realization that has realized the PSN network.
Above-described embodiment of the present invention does not constitute the qualification to protection range of the present invention.Any modification of within spirit of the present invention and principle, being done, be equal to replacement and improvement etc., all should be included within the claim protection range of the present invention.
Claims (10)
1. a packet switching network PSN transmits the method for clock synchronization information, and said packet switching network comprises at least 2 network segments, connects adjacent a PSN network segment and the 2nd PSN network segment by communication node, it is characterized in that said method comprises:
On communication node, obtain clock synchronization information from a PSN network segment according to the first synchronised clock mode; Said clock synchronization information is the clock synchronization information of packet switching network circuit emulation service CESoPSN;
The clock synchronization information that obtains is transmitted to the 2nd PSN network segment according to the second synchronised clock mode.
2. the method for packet switching network to transmit clock synchronizing information according to claim 1 is characterized in that: the said first synchronised clock mode or the second synchronised clock mode comprise that common synchronised clock mode, difference recover synchronised clock mode or self-adaptive recovery synchronised clock mode.
3. like the method for the said packet switching network to transmit clock synchronizing information of claim 2; It is characterized in that; When the first or second synchronised clock mode was common synchronised clock mode or difference recovery synchronised clock mode, said method also comprised: on communication node, receive the external clock reference that is used for carrying out clock synchronization.
4. the method for packet switching network to transmit clock synchronizing information according to claim 1, it is characterized in that: said communication node comprises first mutual linkage function IWF equipment and the 2nd IWF equipment;
A said IWF equipment connects a PSN network segment with the PSN interface, obtains clock synchronization information according to the first synchronised clock mode, and this clock synchronization information is passed to the 2nd IWF equipment;
Said the 2nd IWF equipment connects the 2nd PSN network segment with the PSN interface, transmits the clock synchronization information that an IWF equipment provides according to the second synchronised clock mode to the 2nd PSN network segment.
5. like the method for the said packet switching network to transmit clock synchronizing information of claim 4; It is characterized in that: said IWF equipment and the 2nd IWF equipment have the time division multiplexing tdm interface respectively, and first passes through the TDM interface transmits clock synchronization information and tdm data to the 2nd IWF equipment.
6. the method for packet switching network to transmit clock synchronizing information according to claim 1; It is characterized in that: said communication node is a communication equipment; Said communication equipment connects a PSN network segment and the 2nd PSN network segment respectively with two PSN interfaces, and the grouping that a PSN network segment is forwarded to the 2nd PSN network segment is directly transmitted with the circuit simulation packet format.
7. the circuit simulation communication equipment of a packet switching network; It is characterized in that: comprise the PSN interface and the 2nd PSN interface, processing unit, first clock unit and the second clock unit that connect the first packet switching network PSN network segment and the 2nd PSN network segment respectively, wherein:
First clock unit obtains clock synchronization information according to the control of processing unit from a PSN network segment; Export clock recovered to the second clock unit, and feed back the grouping tranmitting data register information of a PSN interface to processing unit according to the clock synchronization information that receives from the second clock unit;
The second clock unit obtains clock synchronization information according to the control of processing unit from the 2nd PSN network segment; Export clock recovered to first clock unit, and feed back the grouping tranmitting data register information of the 2nd PSN interface to processing unit according to the clock synchronization information that receives from first clock unit;
The form that processing unit directly divides into groups with circuit simulation between first and second PSN interface is transmitted and is divided into groups; Comprise according to the grouping tranmitting data register information of a PSN interface of first clock unit feedback and dividing into groups, and the grouping tranmitting data register information of the 2nd PSN interface that feeds back according to the second clock unit is divided into groups to the 2nd PSN network segment transtation mission circuit emulation to a PSN network segment transtation mission circuit emulation.
8. like the circuit simulation communication equipment of the said packet switching network of claim 7, it is characterized in that: said first clock unit also obtains clock synchronization information according to the synchronised clock that receives from first external clock reference;
Said second clock unit also obtains clock synchronization information according to the synchronised clock that receives from second external clock reference.
9. like the circuit simulation communication equipment of claim 7 or 8 said packet switching networks, it is characterized in that said communication equipment also comprises the time division multiplexing tdm interface, be used for external TDM equipment;
The clock that said processing unit provides according to first clock unit or second clock unit carry out TDM interface and a PSN interface or and the 2nd PSN interface between Data Format Transform.
10. like the communication equipment of the said packet switching network of claim 7, it is characterized in that: a said PSN interface and the 2nd PSN interface are two logic interfacings of same physical port.
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| CN2007100007778A CN101227381B (en) | 2007-01-19 | 2007-01-19 | Method for packet switching network to transmit clock synchronizing information and circuit simulation communication equipment |
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| CN102143127A (en) * | 2010-06-24 | 2011-08-03 | 华为技术有限公司 | Time synchronization method, time synchronization system and network equipment |
| WO2011103831A2 (en) * | 2011-04-18 | 2011-09-01 | 华为技术有限公司 | Clock signal transfer method in communication network system and the communication network system thereof |
| CN103117846B (en) | 2012-12-31 | 2016-01-13 | 华为技术有限公司 | The method, apparatus and system of transmission data |
| CN104144023B (en) * | 2013-05-10 | 2017-07-14 | 中国电信股份有限公司 | The methods, devices and systems synchronous for clock |
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| WO2005069521A1 (en) * | 2004-01-09 | 2005-07-28 | Thomson Licensing | Time synchronizing device and process and associated products |
| CN1761183A (en) * | 2004-10-15 | 2006-04-19 | 三星电子株式会社 | Time allocation method used therein at the synchronous ethernet network |
| CN1866830A (en) * | 2005-07-29 | 2006-11-22 | 华为技术有限公司 | Method for realizing media gateway synchronization in communication system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2005069521A1 (en) * | 2004-01-09 | 2005-07-28 | Thomson Licensing | Time synchronizing device and process and associated products |
| CN1761183A (en) * | 2004-10-15 | 2006-04-19 | 三星电子株式会社 | Time allocation method used therein at the synchronous ethernet network |
| CN1866830A (en) * | 2005-07-29 | 2006-11-22 | 华为技术有限公司 | Method for realizing media gateway synchronization in communication system |
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