CN105323028A - Time synchronization method, equipment and system - Google Patents
Time synchronization method, equipment and system Download PDFInfo
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- CN105323028A CN105323028A CN201410375066.9A CN201410375066A CN105323028A CN 105323028 A CN105323028 A CN 105323028A CN 201410375066 A CN201410375066 A CN 201410375066A CN 105323028 A CN105323028 A CN 105323028A
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- onu
- timestamp
- base station
- olt
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- 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
- H04J3/0661—Clock or time synchronisation among packet nodes using timestamps
- H04J3/0667—Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/1336—Synchronisation
Abstract
The invention discloses a time synchronization method. The time synchronization method comprises the following steps that: an OLT sends a synchronous message to a base station through an ONU; after receiving the synchronous message sent by the OLT, the ONU carries a first timestamp in the synchronous message and forwards the synchronous message to the base station; the first timestamp is the local time of the ONU itself, which is recorded when the synchronous message is forwarded; after receiving the synchronous message forwarded by the ONU, the base station sends a delay request message to the OLT through the ONU; after receiving the delay request message sent by the base station, the ONU carries a fourth timestamp in the delay request message and forwards the delay request message to the OLT; the fourth timestamp is the local time of the ONU itself, which is recorded when the delay request message is received; and, after receiving the delay request message forwarded by the ONU, the OLT carries the fourth timestamp in a delay response message and sends the delay response message to the base station. The invention further discloses a time synchronization method for the OLT, a time synchronization method for the ONU, the OLT, the ONU and a time synchronization system.
Description
Technical field
The present invention relates to wireless communication field Time synchronization technique, particularly relate to a kind of method for synchronizing time, equipment and system.
Background technology
EPON (PassiveOpticalNetwork, PON) is a kind of prefect dielectric network, avoids electromagnetic interference and the effects of lightning of external equipment, decreases the failure rate of circuit and external equipment, improve system reliability; Meanwhile, maintenance cost is saved.The type of PON is mainly divided into Gigabit Passive Optical Network (GPON) and Ethernet passive optical network (EPON), the network configuration of two types is identical, by optical line terminal (OpticalLineTerminal, OLT), optical branching device (OpticalDistributionNode, ODN) and optical network unit (OpticalNetworkUnit, ONU) composition.General employing Tree topology structure in PON, as shown in Figure 1, OLT with ODN is connected, multiple ONU is hung under ODN, between OLT and ONU, downlink data is by broadcast mode, and upstream data uses channel by time division multiplexing mode, OLT connects by IP network and Synchronous Optical Network (SynchronousOpticalNetwork, SONET) core net of the composition such as net, connects base station under ONU.Wherein, base station requests realizes time synchronized, usually, base station answers prioritizing selection satellite receiver to carry out aerial time service, but ground time service mode can be adopted for the base station that cannot realize aerial time service, ground time service requires to have a time source equipment GrandMaster at least, step by step time synchronization information is delivered to base station by core net.
IEEE1588 has set forth the principle realizing time synchronized, has formulated accurate time synchronization protocol (PrecisionTimeProtocol, PTP), transmits time stamp realize time synchronized by PTP message interaction.IEEE1588 supports ordinary clock (OC), boundary clock (BC), transparent clock (TC) three kinds of clock models.In prior art, usual employing boundary clock model realizes time synchronized, as shown in Figure 2, OLT realizes time synchronized as 1588 from clock Slave and upper level clock source, ONU adopts ITU-TG.984 or IEEE802.1AS to realize and the time synchronized of OLT, ONU as 1588 master clock Master downwards first device time synchronization information is provided; Wherein, OLT and ONU is equivalent to jointly serve as boundary clock.
Inventor is realizing in process of the present invention, finds that the existing scheme realizing time synchronized based on EPON at least exists following defect:
In prior art, OLT realizes time synchronized as carrying out PTP message interaction from clock Slave and upper level clock source, and ONU adopts ITU-TG.984 or IEEE802.1AS to realize the time synchronized with OLT; ONU carries out PTP message interaction with next stage clock source again as master clock Master and realizes time synchronized, owing to having blocked PTP message on PON, some property parameters that OLT obtains from the PTP message of upper level clock source cannot be delivered to ONU, cause the discontinuous of PTP protocol.
Summary of the invention
In view of this, the embodiment of the present invention is expected to provide a kind of method for synchronizing time, equipment and system, can not only ensure the continuity of PTP protocol, accurately can also realize time synchronized.
For achieving the above object, technical scheme of the present invention is achieved in that
Embodiments provide a kind of method for synchronizing time, the method comprises:
Synchronization message is sent to base station through ONU by OLT;
Described ONU will stab and be carried on described synchronization message and be transmitted to base station after receiving the synchronization message that described OLT sends the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message;
Latency request message is sent to described OLT through described ONU after receiving the synchronization message of described ONU forwarding by described base station; And record very first time stamp, the second timestamp and the 3rd timestamp, the local zone time of the described base station self that described second timestamp records when being and receiving described synchronization message, the local zone time of the described base station self of recording when described 3rd timestamp is and sends described latency request message;
4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message after receiving the latency request message of described base station transmission by described ONU;
Described 4th timestamp is carried on time delay response message and sends to base station after receiving the latency request message of described ONU forwarding by described OLT.
In such scheme, described method also comprises:
Synchronization message is periodically sent to described base station through described ONU by described OLT.
In such scheme, described OLT is by synchronization message before described ONU sends to described base station, and described method also comprises:
Described OLT periodically carries out PTP message interaction with upper level clock source, adjusts the local zone time of self; And the temporal information adjusted needed for described ONU is carried on oam message sends to described ONU, the temporal information of carrying in described oam message is used to indicate the local zone time that described ONU adjusts self.
In such scheme, described method also comprises:
Described base station receives the time delay response message that described OLT sends, and carries the 4th timestamp in described time delay response message; And according to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self.
Embodiments provide a kind of method that OLT carries out time synchronized, the method comprises:
Synchronization message is sent to base station through ONU;
Receive the latency request message that described ONU forwards, in described latency request message, carry the 4th timestamp;
Described 4th timestamp is carried on time delay response message and sends to base station.
In such scheme, described method also comprises:
Periodically synchronization message is sent to described base station through described ONU.
In such scheme, by synchronization message before described ONU sends to described base station, described method also comprises:
Periodically carry out PTP message interaction with upper level clock source, adjust the local zone time of self;
And the temporal information adjusted needed for described ONU is carried on oam message sends to described ONU, temporal information entrained in described oam message is used to indicate the local zone time that described ONU adjusts self.
Embodiments provide a kind of method that ONU carries out time synchronized, the method comprises:
After receiving the synchronization message that optical line terminal OLT sends, will stab the very first time and be carried on described synchronization message and be transmitted to base station, the local zone time of described ONU of described very first time stamp for recording when forwarding described synchronization message;
After receiving the latency request message of described base station transmission, the 4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU recorded when described 4th timestamp is and receives described latency request message.
In such scheme, before described ONU receives the synchronization message of described OLT transmission, described method also comprises:
Safeguard the clock synchronous of described ONU local zone time and described OLT local zone time;
Periodically receive oam message, in described oam message, carry the temporal information of the required adjustment of described ONU;
The local zone time of described ONU self is adjusted according to the temporal information of carrying in described oam message.
Based on said method, embodiments provide a kind of OLT, this OLT comprises: the first sending module, the first receiver module, the second sending module; Wherein,
Described first sending module, for sending to base station by synchronization message through ONU;
Described first receiver module, for receiving the latency request message that described ONU forwards, carries the 4th timestamp in described latency request message;
Described second sending module, sends to described base station for described 4th timestamp is carried on time delay response message.
In such scheme, described first sending module, also for periodically synchronization message being sent to described base station through ONU.
In such scheme, described OLT also comprises:
Very first time synchronization module, for periodically carrying out PTP message interaction with upper level clock source, adjusts the local zone time of self;
3rd sending module, the temporal information for adjusting needed for described ONU is carried on oam message and sends to described ONU, and the temporal information of carrying in described oam message is used to indicate the local zone time that described ONU adjusts self.
In such scheme, described very first time synchronization module, also for periodically carrying out PTP message interaction with upper level clock source, adjusts the local zone time of self.
Based on said method, embodiments provide a kind of ONU, this ONU comprises: the second receiver module, the 4th sending module, the 3rd receiver module, the 5th sending module; Wherein,
Described second receiver module, for receiving the synchronization message that OLT sends;
Described 4th sending module, is carried on described synchronization message is transmitted to base station for stabbing the very first time, the local zone time of described ONU self of described very first time stamp for recording when being forwarded to described synchronization message;
Described 3rd receiver module, for receiving the latency request message that described base station sends;
Described 5th sending module, is transmitted to described OLT for the 4th timestamp is carried on described latency request message, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message.
In such scheme, described ONU also comprises:
4th receiver module, for receiving oam message, carries the temporal information of the required adjustment of described ONU in described oam message;
Second time synchronized module, for adjusting the local zone time of described ONU self according to the temporal information of carrying in described oam message.
Based on said method, embodiments provide a kind of clock synchronization system, this system comprises: OLT, ONU, base station; Wherein,
Described OLT, for sending to described base station by synchronization message through described ONU; Receive the latency request message that described ONU forwards, in described latency request message, carry the 4th timestamp; Described 4th timestamp is carried on time delay response message and sends to base station;
Described ONU, after receiving synchronization message that OLT described in light sends, will stab and be carried on described synchronization message and be transmitted to base station the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message; After receiving the latency request message of described base station transmission, the 4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message;
Described base station, for receiving the synchronization message that described ONU forwards, and recording very first time stamp and the second timestamp, described very first time stamp is carried in synchronization message, the local zone time of the described base station self of recording when described second timestamp is and receives described synchronization message; Latency request message is sent to described OLT through described ONU, and records the 3rd timestamp, the local zone time of the described base station self of recording when described 3rd timestamp is and sends described latency request message; Receive the time delay response message that described OLT sends, in described time delay response message, carry the 4th timestamp; According to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self.
The method for synchronizing time that the embodiment of the present invention provides, equipment and system, synchronization message is sent to base station through ONU by OLT; ONU will stab and be carried on described synchronization message and be transmitted to base station after receiving the synchronization message that OLT sends the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message; Latency request message is sent to OLT through ONU after receiving the synchronization message of ONU forwarding by base station; 4th timestamp is carried on described latency request message and is transmitted to OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message after receiving the latency request message of base station transmission by ONU; Described 4th timestamp is carried on time delay response message and sends to base station after receiving the latency request message of ONU forwarding by OLT; So, the property parameters in the PTP message obtained from upper level is directly delivered to base station by embodiment of the present invention OLT, can not only ensure the continuity of PTP protocol, accurately can also realize time synchronized.
Accompanying drawing explanation
Fig. 1 is the composition structural representation of embodiment of the present invention EPON;
Fig. 2 is the method flow schematic diagram realizing time synchronized in prior art of the present invention based on EPON;
Fig. 3 is the composition structural representation of embodiment of the present invention clock synchronization system;
Fig. 4 is the schematic diagram of embodiment of the present invention time synchronized flow process;
Fig. 5 is the method flow schematic diagram that embodiment of the present invention OLT carries out time synchronized;
Fig. 6 is the structural representation of embodiment of the present invention Sync message and Delay_req message;
Fig. 7 is the method flow schematic diagram that embodiment of the present invention ONU carries out time synchronized;
Fig. 8 a is the port match rule schematic diagram of the message arrangement that embodiment of the present invention ONU encapsulates for Layer 2 Multicast mode;
Fig. 8 b is the port match rule schematic diagram of embodiment of the present invention ONU for the message arrangement of IPv4+UDP protocol encapsulation;
Fig. 8 c is the port match rule schematic diagram of embodiment of the present invention ONU for the message arrangement of IPv6+UDP protocol encapsulation;
Fig. 9 is the method flow schematic diagram that time synchronized is carried out in embodiment of the present invention base station;
Figure 10 is the composition structural representation of embodiment of the present invention OLT;
Figure 11 is the composition structural representation of embodiment of the present invention ONU.
Embodiment
The embodiment of the present invention is applied to clock synchronization system, mainly comprises in this clock synchronization system: OLT, ONU, base station; This clock synchronization system realizes time synchronized by PTP message passing time stamp; Wherein, described OLT carries out PTP message interaction as from clock Slave and upper level clock source, the time synchronized realizing OLT and upper level clock source is stabbed by passing time, and the local zone time after adjustment is sent to described ONU, make described ONU realize the time synchronized with described OLT; Meanwhile, described OLT carries out PTP message interaction as master clock Master by described ONU and described base station, makes described base station realize the time synchronized with described OLT by passing time stamp; Property parameters in the PTP message obtained from upper level clock source is directly delivered to base station by OLT described in the embodiment of the present invention, ONU can not change the property parameters in PTP message, thus ensure that the continuity of PTP protocol, and accurately can realize time synchronized.
Here, PTP message comprises event Event message and general General message; Wherein, Event message all needs precise time to stab in transmission and receiving course, and can excite transmission subsequent message, such as, and Sync message, latency request Delay_req message etc.; General message is used for transfer data information and administrative message, does not need precise time to stab, can not excite transmission subsequent message in transmission and receiving course, such as, and time delay response Delay_resp message, notice Announce message etc.
Below in conjunction with accompanying drawing, the specific embodiment of the present invention is described.
The composition structural representation of clock synchronization system of Fig. 3 for providing in the embodiment of the present invention, as shown in Figure 3, this clock synchronization system comprises: OLT300, ONU301, base station 302; Wherein,
Described OLT300, for sending to described base station by synchronous Sync message through described ONU; Receive the latency request Delay-req message that described ONU forwards, in described Delay-req message, carry the 4th timestamp; Described 4th timestamp is carried on time delay response Delay-resp message and sends to described base station;
Described ONU301, after receiving Sync message that described OLT sends, will stab the very first time and be carried on described Sync message and be transmitted to described base station, described very first time stamp is for forwarding the local zone time of the described ONU self of record when described Sync message is left; After receiving the Delay-req message of described base station transmission, the 4th timestamp is carried on described Delay-req message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described Delay-req message;
Described base station 302, for receiving the Sync message that described ONU forwards, and recording very first time stamp and the second timestamp, described very first time stamp is carried in Sync message, the local zone time of the described base station self of recording when described second timestamp is and receives described Sync message; Delay-req message is sent to described OLT through described ONU, and records the 3rd timestamp, the local zone time of the described base station self of recording when described 3rd timestamp is and sends described latency request Delay-req message; Receive the Delay-resp message that described OLT sends, in described Delay-resp message, carry the 4th timestamp; According to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self.
Here, specifically how according to the local zone time of very first time stamp, the second timestamp, the 3rd timestamp and the 4th timestamp adjustment self, have a detailed description in hereafter step 905.
Based on said system framework, as shown in Figure 4, the process realizing time synchronized based on clock synchronization system shown in Fig. 3 that the embodiment of the present invention provides comprises:
Step a:OLT and upper level clock source carry out PTP message interaction, adjust the local zone time of self, realize the time synchronized with upper level clock source, and the local zone time after adjustment is carried on oam (OperationAdministrationandMaintenance, OAM) message and sends to described ONU;
Step b: when described ONU receives OAM message, according to the local zone time of the temporal information adjustment of carrying in described oam message self, realizes the time synchronized with described OLT;
Step c: Sync message is sent to described base station through described ONU by described OLT;
Steps d: described ONU will stab T after receiving the Sync message of described OLT transmission the very first time
1be carried on described Sync message and be transmitted to base station, described very first time stamp T
1the local zone time of the described ONU of record when described Sync message is left is forwarded for described ONU;
Step e: described base station receives the Sync message that described ONU forwards, and record very first time stamp T
1and second time stamp T
2, described very first time stamp T
1be carried in Sync message, described second time stamp T
2for the local zone time of described base station recorded when described base station receives described Sync message;
Step f: Delay-req message is sent to described OLT through described ONU by described base station, and record the 3rd time stamp T
3, described 3rd time stamp T
3for the local zone time of described base station self recorded when described base station sends described Delay-req message;
Step g: after described ONU receives the Delay-req message of described base station transmission, by the 4th time stamp T
4be carried on described Delay-req message and be transmitted to described OLT, described 4th time stamp T
4for the local zone time of described ONU self recorded when described ONU receives described Delay-req message;
Step h: described OLT receive described ONU forward Delay-req message, carry the 4th time stamp T in described Delay-req message
4; And described 4th timestamp is taken T
4be with and send to base station in Delay-resp message;
Step I: when described base station receives the Delay-resp message of described OLT transmission, according to described very first time stamp T
1, described second time stamp T
2, described 3rd time stamp T
3and described 4th time stamp T
4, calculating path postpones, and adjusts the local zone time of self, thus realizes the time synchronized with described OLT.
Here, specifically how according to described very first time stamp T
1, described second time stamp T
2, described 3rd time stamp T
3and described 4th time stamp T
4adjust the local zone time of self, have a detailed description in hereafter step 905.
As shown in Figure 5, the OLT that the embodiment of the present invention provides carries out the flow process of time synchronized, and specific implementation step comprises:
Step S500: Sync message is sent to base station through ONU;
In this step, before Sync message is sent to described ONU, according to setting-up time interval or setpoint frequency mode, namely periodically carry out PTP message interaction with upper level clock source, adjust the local zone time of self, as shown in Figure 4, specific implementation is as follows:
Upper level clock source periodically will stab and be carried on Sync message and send to described OLT the very first time, the local zone time of described upper level clock source of very first time stamp for recording when sending described Sync message;
When described OLT receives the Sync message of described upper level clock source transmission, record the second timestamp, the local zone time of the described OLT recorded when described second timestamp is and receives described Sync message;
Delay_req message is sent to described ONU by described OLT; And record the 3rd timestamp, the local zone time of the described OLT recorded when described 3rd timestamp is and sends described Delay_req message;
When described upper level clock source receives the Delay_req message of described OLT transmission, the 4th timestamp is carried on Delay_resp message and sends to described OLT;
When described OLT receives the Delay_resp message of described upper level clock source transmission, according to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self;
Concrete, according to the path delay T ' of upper level clock source described in following formulae discovery to described OLT:
T′＝{T
4-T
1-(T
3-T
2)}/2
Wherein, T
1for described very first time stamp, T
2for described second timestamp, T
3for described 3rd timestamp, T
4for described 4th timestamp.
Reference time T is adjusted according to following formula:
T＝T
1+T′
The local zone time of self is adjusted according to adjustment reference time T.
In this step, after described OLT adjusts the local zone time of self, the temporal information adjusted needed for described ONU is carried on OAM message and sends to described ONU, the temporal information of carrying in described OAM message is used to indicate the local zone time that described ONU adjusts self, and described temporal information comprises the information such as the local zone time after described OLT adjustment.
In this step, as shown in Figure 6, implication and the function of each field all have explanation to the structure of Sync message in the prior art, repeat no more here; Wherein, timestamp field OriginTimeStamp be used for memory time stamp, its memory capacity is 10 bytes, comprise timestamp second and nanosecond value; When Sync message is sent to described ONU by described OLT, transmitting time can be recorded as transmitting time stamp and be carried in the OriginTimeStamp field of described Sync message and send to described ONU; Also described ONU can be sent to by after the OriginTimeStamp field zero filling of described Sync message.
Step S501: receive the Delay-req message that described ONU forwards, carry the 4th timestamp in described Delay-req message.
In this step, the structure of described Delay-req message is identical with described Sync message, and as shown in Figure 5, implication and the function of each field all have explanation in the prior art, repeat no more here; Wherein, described 4th timestamp is stored in the OriginTimeStamp field of described Delay-req message.
Step S502: described 4th timestamp is carried on Delay_resp message and sends to base station.
Further, the Announce message being used for Transfer Parameters obtained from upper level clock source periodically can be sent to described base station through described ONU by described OLT, because the property parameters in described Announce message can not change on ONU, therefore, ensure that the continuity of PTP protocol.
As shown in Figure 7, the ONU that the embodiment of the present invention provides carries out the flow process of time synchronized, and specific implementation step comprises:
Step S701: receive the Sync message that OLT sends.
In this step, before receiving the Sync message of OLT transmission, periodically receive the OAM message that described OLT sends, in described OAM message, carry the temporal information of the required adjustment of described ONU; According to the local zone time of described temporal information adjustment self, to safeguard the clock synchronous of described ONU local zone time and described OLT local zone time.
Here, belong to prior art according to described ONU according to the embodiment of the local zone time of described temporal information adjustment self, repeat no more.
In this step, the Sync message that described OLT sends enters described ONU by optic path, ONU need to user side go out to message filter, to find Sync message, therefore, described ONU needs to go out in user side to preset corresponding matched rule to port needles to the Sync message that different agreement encapsulates:
When filtering described Sync message, for the Sync message that Layer 2 Multicast mode encapsulates, as shown in Figure 8 a, the port match rule preset is:
EthType(0x88F7)+MsgType(0x0)
For the Sync message of IPv4+UDP protocol encapsulation, as shown in Figure 8 b, the matched rule preset is:
EthType(0x0800)+DstPort(319)+MsgType(0x0)
For the Sync message of IPv6+UDP protocol encapsulation, as shown in Figure 8 c, the matched rule preset is:
EthType(0x86DD)+DstPort(319)+MsgType(0x0)
Wherein, EthType is ethernet type; DstPort is UDP destination interface; MsgType is PTP type of message; 0x0 is the ID of synchronous Sync message.
In this step, the matched rule according to presetting filters described Sync message, when mate with described matched rule, determines to receive the Sync message of OLT transmission and to be sent to base station.
Step S702: will stab the very first time and be carried on described Sync message and be transmitted to base station, described very first time stamp is for forwarding the local zone time of the described ONU of record when described Sync message is left.
In this step, described ONU forwards described Sync message when leaving, and the local zone time recording self is very first time stamp T
1, be stamp T of the described very first time by the content modification in the originTimeStamp field of described Sync message
1, and again calculation check and, the School Affairs recalculated is added in the respective field of described Sync message, then, by carry the described very first time stamp Sync message send to base station.
Step S703: receive the Delay-req message that described base station sends;
In this step, the Delay-req message that described base station sends enters described ONU by line transmission, ONU need to user side enter to message filter, to find Delay-req message, therefore, described ONU needs to enter in user side to preset corresponding matched rule to port needles to the Delay-req message that different agreement encapsulates:
When filtering described Delay-req message, for the Delay-req message that Layer 2 Multicast mode encapsulates, as shown in Figure 8 a, the matched rule preset is:
EthType(0x88F7)+MsgType(0x1)
For the Delay-req message of IPv4+UDP protocol encapsulation, as shown in Figure 8 b, the matched rule preset is:
EthType(0x0800)+DstPort(319)+MsgType(0x1)
For the Delay-req message of IPv6+UDP protocol encapsulation, as shown in Figure 8 c, the matched rule preset is:
EthType(0x86DD)+DstPort(319)+MsgType(0x1)
Wherein, EthType is ethernet type; DstPort is UDP destination interface; MsgType is PTP type of message; 0x1 is the ID of Delay_req message.
In this step, the matched rule according to presetting filters described Delay-req message, when mating with described matched rule, determines the Delay-req message receiving base station transmission.
Step S704: the 4th timestamp is carried on described Delay-req message and is transmitted to described OLT, the local zone time of the described ONU recorded when described 4th timestamp is and receives described Delay-req message.
In this step, when described ONU receives described Delay-req message, the local zone time recording self is the 4th time stamp T
4, be described 4th time stamp T by the content modification in the originTimeStamp field of described Delay-req message
4, and again calculation check and, the School Affairs recalculated is added in the respective field of described Delay-req message, then, the described Delay-req message carrying described 4th timestamp is transmitted to described OLT.
As shown in Figure 9, the flow process of time synchronized is carried out in the base station that the embodiment of the present invention provides, and specific implementation step comprises:
Step S900: receive the Sync message that described ONU forwards, carries very first time stamp T in described Sync message
1;
Step S901: record the second time stamp T
2, described second time stamp T
2for the local zone time of described base station self recorded when receiving described Sync message;
Step S902: Delay-req message is sent to described ONU;
Step S903: record the 3rd time stamp T
3, described 3rd time stamp T
3for the local zone time of described base station self recorded when sending described Delay-req message;
Step S904: receive the Delay_resp message that described OLT sends, carry the 4th time stamp T in described Delay_resp message
4;
Step S905: according to described very first time stamp T
1, described second time stamp T
2, described 3rd time stamp T
3and described 4th time stamp T
4, calculating path postpones, and adjusts the local zone time of described base station self.
Concrete, first, according to the path delay T ' of ONU described in following formulae discovery to described base station:
T′＝{T
4-T
1-(T
3-T
2)}/2
Wherein, T
1for described very first time stamp, T
2for described second timestamp, T
3for described 3rd timestamp, T
4for described 4th timestamp.
Then, reference time T is adjusted according to following formula:
T＝T
1+T′
The local zone time of described base station self is adjusted according to adjustment reference time T.
In the embodiment of the present invention, OLT carries out PTP message interaction as from clock Slave and upper level clock source, the time synchronized realized with upper level clock source is stabbed by passing time, and the local zone time after adjustment is sent to described ONU, make described ONU realize the time synchronized with described OLT; Meanwhile, described OLT carries out PTP message interaction as master clock Master by described ONU and described base station, makes described base station realize the time synchronized with described OLT by passing time stamp; So, the property parameters in the PTP message obtained from upper level clock source is directly sent to described base station by described OLT, thus ensure that the continuity of PTP protocol, and accurately can realize time synchronized.
For realizing said method, the embodiment of the present invention additionally provides a kind of OLT, ONU, and the principle of dealing with problems due to this OLT, ONU is similar to method, and therefore, the enforcement of equipment see the enforcement of preceding method, can repeat part and repeat no more.
As shown in Figure 10, the OLT that the embodiment of the present invention provides, this OLT comprises: the first sending module 100, first receiver module 101, second sending module 102; Wherein,
Described first sending module 100, for sending to base station by synchronization message through ONU;
Described first receiver module 101, for receiving the latency request message that described ONU forwards, carries the 4th timestamp in described latency request message;
Described second sending module 102, sends to described base station for described 4th timestamp is carried on time delay response message.
The dividing mode of above functional module is only the preferred implementation of one that the embodiment of the present invention provides, and the dividing mode of functional module is not construed as limiting the invention.
In concrete enforcement, described first sending module 100, also for periodically synchronization message being sent to described base station through described ONU.
In concrete enforcement, described OLT also comprises:
Very first time synchronization module 103, for periodically carrying out PTP message interaction with upper level clock source, adjusts the local zone time of self;
3rd sending module 104, the temporal information for adjusting needed for described ONU is carried on oam message and sends to described ONU, and the temporal information in described oam message is used to indicate the local zone time that described ONU adjusts self.
As shown in figure 11, the ONU that the embodiment of the present invention provides, this ONU comprises: the second receiver module 110, the 4th sending module 111, the 3rd receiver module 112, the 5th sending module 113; Wherein,
Described second receiver module 110, for receiving the synchronization message that described OLT sends;
Described 4th sending module 111, is carried on described synchronization message is transmitted to base station for stabbing the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message;
Described 3rd receiver module 112, for receiving the latency request message that described base station sends;
Described 5th sending module 113, is transmitted to described OLT for the 4th timestamp is carried on described latency request message, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message.
The dividing mode of above functional module is only the preferred implementation of one that the embodiment of the present invention provides, and the dividing mode of functional module is not construed as limiting the invention.
In concrete enforcement, described ONU also comprises:
4th receiver module 114, for periodically receiving oam message, carries the temporal information of the required adjustment of described ONU in described oam message;
Second time synchronized module 115, for adjusting the local zone time of described ONU self according to the temporal information of carrying in described maintenance management message.
In actual applications, described first sending module 100, first receiver module 101, second sending module 102, very first time synchronization module 103, the 3rd sending module 104 all can realize by being positioned at the central processing unit (CPU) of OLT, microprocessor (MPU), digital signal processor (DSP) or field programmable gate array (FPGA); Described second receiver module 110, the 4th sending module 111, the 3rd receiver module 112, the 5th sending module 113, the 4th receiver module 114, second time synchronized module 115 all can realize by being positioned at the central processing unit (CPU) of ONU, microprocessor (MPU), digital signal processor (DSP), field programmable gate array (FPGA) or PHY chip.
Method of the present invention is not limited to the embodiment described in embodiment, and those skilled in the art's technical scheme according to the present invention draws and other execution mode belongs to technological innovation scope of the present invention equally.
Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.
Claims (15)
1. a method for synchronizing time, is characterized in that, described method comprises:
Synchronization message is sent to base station through optical network unit ONU by optical line terminal OLT;
Described ONU will stab and be carried on described synchronization message and be transmitted to base station after receiving the synchronization message that described OLT sends the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message;
Latency request message is sent to described OLT through described ONU after receiving the synchronization message of described ONU forwarding by described base station; And record very first time stamp, the second timestamp and the 3rd timestamp, the local zone time of the described base station self that described second timestamp records when being and receiving described synchronization message, the local zone time of the described base station self of recording when described 3rd timestamp is and sends described latency request message;
4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message after receiving the latency request message of described base station transmission by described ONU;
Described 4th timestamp is carried on time delay response message and sends to base station after receiving the latency request message of described ONU forwarding by described OLT.
2. method according to claim 1, is characterized in that, described method also comprises:
Synchronization message is periodically sent to described base station through described ONU by described OLT.
3. method according to claim 1, is characterized in that, described OLT is by synchronization message before described ONU sends to described base station, and described method also comprises:
Described OLT periodically carries out PTP message interaction with upper level clock source, adjusts the local zone time of self; And the temporal information adjusted needed for described ONU is carried on oam message sends to described ONU, the temporal information of carrying in described oam message is used to indicate the local zone time that described ONU adjusts self.
4. the method according to any one of claims 1 to 3, is characterized in that, described method also comprises:
Described base station receives the time delay response message that described OLT sends, and carries the 4th timestamp in described time delay response message; And according to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self.
5. optical line terminal OLT carries out a method for time synchronized, it is characterized in that, described method comprises:
Synchronization message is sent to base station through optical network unit ONU;
Receive the latency request message that described ONU forwards, in described latency request message, carry the 4th timestamp;
Described 4th timestamp is carried on time delay response message and sends to base station.
6. method according to claim 5, is characterized in that, described method also comprises:
Periodically synchronization message is sent to described base station through described ONU.
7. the method according to claim 5 or 6, is characterized in that, by synchronization message before described ONU sends to described base station, described method also comprises:
Periodically carry out PTP message interaction with upper level clock source, adjust the local zone time of self;
And the temporal information adjusted needed for described ONU is carried on oam message sends to described ONU, the temporal information of carrying in described oam message is used to indicate the local zone time that described ONU adjusts self.
8. optical network unit ONU carries out a method for time synchronized, it is characterized in that, described method comprises:
After receiving the synchronization message that optical line terminal OLT sends, will stab the very first time and be carried on described synchronization message and be transmitted to base station, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message;
After receiving the latency request message of described base station transmission, the 4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message.
9. method according to claim 8, is characterized in that, before the synchronization message that the described OLT of described reception sends, described method also comprises:
Periodically receive oam message, in described oam message, carry the temporal information of the required adjustment of described ONU;
The local zone time of described ONU self is adjusted according to the temporal information of carrying in described oam message.
10. an optical line terminal OLT, is characterized in that, described OLT comprises: the first sending module, the first receiver module, the second sending module; Wherein,
Described first sending module, for sending to described base station by synchronization message through optical network unit ONU;
Described first receiver module, for receiving the latency request message that described ONU forwards, carries the 4th timestamp in described latency request message;
Described second sending module, sends to base station for described 4th timestamp is carried on time delay response message.
11. OLT according to claim 10, is characterized in that, described first sending module, also for periodically synchronization message being sent to described base station through described ONU.
12. OLT according to claim 10 or 11, it is characterized in that, described OLT also comprises:
Very first time synchronization module, for periodically carrying out PTP message interaction with upper level clock source, adjusts the local zone time of self;
3rd sending module, send to described ONU for the temporal information needed for described ONU is carried on oam message, the temporal information of carrying in described oam message is used to indicate the local zone time that described ONU adjusts self.
13. 1 kinds of optical network unit ONU, is characterized in that, described ONU comprises: the second receiver module, the 4th sending module, the 3rd receiver module, the 5th sending module; Wherein,
Described second receiver module, for receiving the synchronization message that optical line terminal OLT sends;
Described 4th sending module, is carried on described synchronization message is transmitted to base station for stabbing the very first time, the local zone time of described ONU self of described very first time stamp for recording when being forwarded to described synchronization message;
Described 3rd receiver module, for receiving the latency request message that described base station sends;
Described 5th sending module, is transmitted to described OLT for the 4th timestamp is carried on described latency request message, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message.
14. ONU according to claim 13, is characterized in that, described ONU also comprises:
4th receiver module, for periodically receiving oam message, carries the temporal information of the required adjustment of described ONU in described oam message;
Second time synchronized module, for adjusting the local zone time of described ONU self according to the temporal information of carrying in described oam message.
15. 1 kinds of clock synchronization systems, is characterized in that, described system comprises: optical line terminal OLT, optical network unit ONU, base station; Wherein,
Described OLT, for sending to described base station by synchronization message through described ONU; Receive the latency request message that described ONU forwards, in described latency request message, carry the 4th timestamp; Described 4th timestamp is carried on time delay response message and sends to base station;
Described ONU, after receiving synchronization message that OLT described in light sends, will stab and be carried on described synchronization message and be transmitted to base station the very first time, the local zone time of described ONU self of described very first time stamp for recording when forwarding described synchronization message; After receiving the latency request message of described base station transmission, the 4th timestamp is carried on described latency request message and is transmitted to described OLT, the local zone time of the described ONU self recorded when described 4th timestamp is and receives described latency request message;
Described base station, for receiving the synchronization message that described ONU forwards, and recording very first time stamp and the second timestamp, described very first time stamp is carried in synchronization message, the local zone time of the described base station self of recording when described second timestamp is and receives described synchronization message; Latency request message is sent to described OLT through described ONU, and records the 3rd timestamp, the local zone time of the described base station self of recording when described 3rd timestamp is and sends described latency request message; Receive the time delay response message that described OLT sends, in described time delay response message, carry the 4th timestamp; According to described very first time stamp, described second timestamp, described 3rd timestamp and described 4th timestamp, calculating path postpones, and adjusts the local zone time of self.
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| PCT/CN2014/086756 WO2015117319A1 (en) | 2014-07-31 | 2014-09-17 | Time synchronization method, device and system |
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