CN104486058B - A kind of PTP system method for synchronizing time and device - Google Patents
A kind of PTP system method for synchronizing time and device Download PDFInfo
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Abstract
A kind of PTP system method for synchronizing time of present invention offer and device, this method include：The deviation that the time is characterized with upstream equipment is obtained according to the time stamp of the time synchronization message interacted with upstream equipment；According to the deviation update synchronizing information that downstream equipment is sent for characterizing the time with upstream equipment, so that the characterization time synchronization between PTP system middle and upper reaches equipment and upstream device.
Description
Technical field
The present invention relates to field of communication technology more particularly to a kind of PTP (Precision Time Protocol, when accurate
Between agreement) system synchronization method and device.
Background technology
PTP is for realizing the precise synchronization between equipment, it can also be used to the Frequency Synchronization between equipment.In PTP
In system, by upstream equipment, downstream equipment issues synchronization time, and the upstream equipment for issuing synchronization time is properly termed as master clock,
And the upstream device for receiving synchronization time is then known as from clock.
When realizing the time synchronization of PTP system, by the time synchronization message from interaction between the master and slave clock of clock log
Time stamp time synchronization message round-trip time difference is calculated by CPU by the way that the time stamp is reported to central processor CPU, and
Round-trip total delay between master and slave clock is calculated according to the round-trip time difference.If network is symmetrical, round-trip total delay
Half be exactly one-way delay, and the clock jitter value between master and slave clock is calculated according to this one-way delay.CPU can be with
Local zone time is adjusted according to the clock jitter value by controlling from clock, it is same between clock and master clock to realize
Step.
However, usually CPU from the clock jitter value calculated between master and slave clock to control from clock according to the clock jitter
Value is longer come the process for adjusting local zone time, if can adjust the time range of local zone time in a time cycle from clock
The outer time synchronization message for receiving master clock transmission, then, CPU can then be controlled from clock in the next time cycle and be adjusted locally
There is relatively large deviation, and the unfixed problem of deviation so as to cause the time between subsequent master and slave clock in time.
Invention content
In view of this, the present invention provides a kind of PTP system method for synchronizing time and device to solve in the prior art
The problem of.
The present invention provides a kind of PTP system method for synchronizing time, and wherein this method includes：
The deviation that the time is characterized with upstream equipment is obtained according to the time stamp of the time synchronization message interacted with upstream equipment；
According to the deviation update synchronizing information that downstream equipment is sent for characterizing the time with upstream equipment.
The present invention also provides a kind of PTP system time synchronism apparatus, described device includes：
Acquiring unit is characterized for being obtained according to the time stamp of the time synchronization message interacted with upstream equipment with upstream equipment
The deviation of time；
Updating unit is used for according to the same of the deviation update downstream equipment transmission for characterizing the time with upstream equipment
Walk information.
PTP system method for synchronizing time and device provided by the invention, using get characterized with upstream equipment when
Between deviation update downstream equipment send synchronizing information so that the table between PTP system middle and upper reaches equipment and upstream device
Levy time synchronization.
Description of the drawings
Fig. 1 is the 1PPS frequencies and phase schematic diagram of upstream equipment and upstream device in the prior art；
Fig. 2 is the PTP system network environment schematic diagram that the embodiment of the present invention is applied；
Fig. 3 is that request-reply mechanism realizes process schematic in the embodiment of the present invention；
Fig. 4 is PTP system method for synchronizing time flow diagram in the embodiment of the present invention；
Fig. 5 is the 1PPS frequencies and phase schematic diagram of middle and upper reaches of embodiment of the present invention equipment and upstream device；
Fig. 6 is local device hardware structure schematic diagram where PTP system time synchronism apparatus in the embodiment of the present invention；
Fig. 7 is the logical construction schematic diagram of PTP system time synchronism apparatus in the embodiment of the present invention.
Specific implementation mode
The network for applying PTP protocol is properly termed as the domains PTP or PTP system, has in PTP system and only there are one synchronous
Clock, also referred to as optimal clock (Grandmaster Clock, GM).It is optimal by the interaction of each equipment room PTP protocol message
The time of clock will finally be transmitted by downward synchronous, thus also can optimal clock be referred to as clock source.
In the time synchronization in realizing PTP system, upstream device (from clock) receives upstream equipment, and (master clock also may be used
To be clock source) synchronization (Sync) message of publication, and pass through the Sync messages and the back message interacted with upstream equipment
(Delay_Req messages and Delay_Resp messages) obtains multiple timestamps, when calculating characterization according to multiple timestamp
Between deviation (Offset).
In the prior art, after calculating the Offset, the local zone time of itself is adjusted according to the Offset from clock, with
Keep the time synchronization with master clock (or clock source).It is assumed that 1 second is a time cycle, it, will after calculating Offset
(1+/- Offset) is stored in the corresponding clearing threshold register of PHY (physical layer) chip, and is receiving internal PHY chip
When 1PPS (1Pulse Per Second, the pulse per second (PPS)) of transmission, opens internal counter and counted, in gate time etc.
In or more than (1+/- Offset) time when, by sending the counter O reset inside 1PPS controls, and restart to count
Number.The 1PPS frequencies and phase schematic diagram of upstream equipment and upstream device shown in please referring to Fig.1, by above-mentioned place repeatedly
The 1PPS of reason, local device output can keep almost the same with the frequency and phase of the 1PPS of upstream equipment, be set to local
The standby time finally remains exactly the same (error is in nano-seconds) with the time of upstream equipment.
However, obtaining the message time stamp of time synchronization message, then Offset calculating is carried out, and using Offset to this
The ground time is adjusted the used time usually all in Millisecond, if (remaining time is or not the end time 1 second time cycle
It is sufficient for calculating Offset and adjusts local zone time) the Sync messages that receive upstream equipment, then CPU then can be when next
Between the period control local device adjust local zone time, there is asking for relatively large deviation so as to cause the time between subsequent upstream and downstream
Topic.
Fig. 2 show a PTP system network environment schematic diagram, includes upstream equipment (R1), local device in PTP system
(R2) and upstream device (R3), wherein R1 are the master clock (Master clock) of R2, and R2 is the master clock of R3, and R2 is R1's
It is the slave clock of R2 from clock (Slave clock), R3.
The process flow of one PTP system method for synchronizing time example of the application is as shown in figure 3, this method can specifically be applied
In PTP equipment in PTP system, this example is illustrated for being applied to a local device, is included the following steps：
Step 301, it is obtained according to the time stamp of the time synchronization message interacted with upstream equipment and characterizes the time with upstream equipment
Deviation；
In each equipment of PTP system, the port for issuing synchronization time is known as main port (Master), and receives synchronization time
Port be then known as from the port (Slave).In initial state, inside local device also unallocated specific master port and from
Port, local device receive upstream equipment transmission Sync messages when, can by BMC (Best Master Clock,
Best master clock) master port in algorithm picks local device and from port, can also be as needed, or randomly select out
Master port and from port subsequently can use the master port chosen and be sent from port or receiving time synchronization message.
It selects behind port, one fixed numbers, example can will be set from the corresponding clearing threshold register in port with the selection
Such as 1 second, clearing threshold register is made no longer to change with calculated clock jitter value.In this example, it is also provided with and institute
It states and resets the corresponding counter of threshold register, when the counting duration of counter reaches preset fixed numbers (such as 1 second),
The counting of the counter is reset into New count of laying equal stress on.During the counter counts, if receiving time synchronization message,
Using the current gate time of counter when receiving time synchronization message as the message time stamp for receiving the time synchronization message
Nanosecond value, using internal system preserve the TOD times as the seconds value of message time stamp.
In the time synchronization in realizing PTP system, can be obtained by the time synchronization message of interaction in request-reply mechanism
Take message time stamp.
PTP system middle and upper reaches equipment downstream equipment sending time synchronization message can there are two types of sending mode, one is
Single-step mode, one is two-step patterns.Under single-step mode, which may include receiving the Sync of upstream equipment R1 publications
Delay_Req (latency request) message that (synchronization) message, local device R2 are replied according to Sync message upstream devices R1,
And receive Delay_Resp (delay is responded) message that upstream equipment is responded according to the Delay_Req messages.And it can basis
The the first time stamp t1 and local device R2 that the Sync Receive messages upstream equipment R1 sends the Sync messages receive institute
When stating Sync messages, by receiving for the second time stamp t2 that the gate time current with the corresponding counter of threshold register is reset is used as
Seconds value, while the TOD times that internal system is preserved are as the seconds value of the second time stamp t2；Local device R2 upstream devices R1 hairs
When sending Delay_Req messages, the third time stamp t3 (acquisition methods are identical as the second time stamp t2) for sending Delay_Req is obtained, with
And the 4th time stamp t4 of Delay_Req messages is received according to Delay_Resp Receive message upstream equipments R1.
Fig. 4 is that upstream equipment realizes process schematic with two-step pattern downstream equipment sending time synchronization message, with list
Mode approach difference is, the first time stamp t1, the first time stamp are not carried in the upstream equipment Sync messages that downstream equipment is sent
The Follow_Up that t1 is sent by downstream equipment (follows) message to carry.Therefore, local device is obtained from Follow_Up messages
Take the first time stamp t1.
In addition, receiving the Sync messages of master port transmission of the upstream equipment by single-step mode, and get first
After time stamp t1, further check whether Correction Field (time complexity curve domain) field in the Sync messages is acquiescence
Value, the content of the field is an other correction value of nanosecond to residence time, if being default value in the field, illustrate this
One time stamp t1 is actual first time stamp t1；If it is not, the first time stamp t1 of the acquisition is then initial first time stamp t1, that is, not
Using the first time stamp of the deviation compensation of the characterization time with upstream equipment, then, initial first time stamp t1 is combined
The numerical value of Correction Field fields is modified, and obtained result is only actual first time stamp t1.
Specifically, after obtaining the first time stamp t1 when sending Sync messages, the Correction of Sync messages is checked
Offset entrained by Field is positive number or negative, if positive number, then by first time stamp nanosecond value with it is described
The nanosecond value of Offset is added, and judges whether numerical value after being added needs carry, i.e., numerical value after being added whether more than 1 second,
If so, using the remainder obtained after the magnitude carry as the nanosecond value of updated first time stamp, by the seconds value after carry
Seconds value as updated first time stamp；If numerical value after being added does not need carry, i.e., numerical value after being added is no more than 1 second,
Then using the numerical value after being added as the nanosecond value of updated first time stamp, the other values of the first time stamp are still constant.
If the Offset is negative, it is greater than or equal to the nanosecond value of the Offset in the nanosecond value of first time stamp
When, then using the nanosecond value of first time stamp subtract the Offset nanosecond value absolute value as described updated
The nanosecond value of one time stamp, the other values of the first time stamp are still constant；It is less than the Offset's in the nanosecond value of first time stamp
Nanosecond value absolute value when, by first time stamp nanosecond value plus after 1 second, then subtract the Offset nanosecond value it is exhausted
To be worth subtract 1 second to get the seconds value to the nanosecond value of updated first time stamp, the first time stamp after obtain numerical value, as update
The seconds value of the first time stamp afterwards.After obtaining updated first time stamp, which is added to described
In Follow_Up messages so that be added to updated first time stamp nanosecond value and seconds value Follow_Up messages
It is sent to upstream device as the synchronizing information.
For example, Correction Field field default values are 0, it is 1407827087s in the first time stamp t1 of acquisition
When (second) 999479955ns (nanosecond), 1407827087s 999479955ns are actual first time stamp t1；If
Correction Field fields are modified to 6876ns, and 1407827087s999479955ns is then initial first time stamp t1,
The 1407827087s 999486831ns that 1407827087s 999479955ns are obtained plus 6876ns are only actual the
One time stamp t1.
After getting the message time stamp t1, t2, t3 and t4, local device can be calculated according to the message time stamp first
The two-way delay time of message interaction, i.e. [ between upstream equipment;(t2–t1)+(t4–t3)].Due to when network is symmetrical, message
Interactive trip path is usually consistent, so;(t2–t1)+(t4–t3)]/ 2 be to be handed between upstream equipment and local device
The one-way delay time of mutual message.Later, (t2-t1) is subtracted into the one-way delay time, as local device is set with upstream
Offset between standby, specially：
Offset=(t2-t1)-[(t2–t1)+(t4–t3)]/2
As an example it is assumed that acquired message time stamp t1, t2, t3 and t4 is respectively：
T1=1407827087s 999479955ns
T2=1407827087s 999486299ns
T3=1407827088s 005866307ns
T4=1407827088s 005873710ns
According to message time stamp t1, t2, t3 and t4 of acquisition using the calculation calculate the Offset be-
1058ns。
In addition, if the topology in network between local device and upstream equipment does not change, each of which is calculated synchronizing cycle
The one-way delay time gone out can be consistent, therefore the embodiment of the present invention can also be within each synchronizing cycle according to acquisition
After t1, t2, t3 and t4 calculate the one-way delay time, which is stored in local device, next same
After getting message time stamp t1 and t2 in step period, you can when (t2-t1) being used to subtract the one-way delay of a computation of Period
Between calculate Offset.After calculating the Offset of local device and upstream equipment, which can be preserved to memory
In, subsequently to look into use.
Step 302, according to the deviation update synchronous letter that downstream equipment is sent for characterizing the time with upstream equipment
Breath.
The master port that downstream equipment sends synchronizing information in the present invention can be multiple, due to each master port of equipment
Port attribute may be different so that the operating method synchronized into row clock is also not quite similar.For example, the master of local device
Port can be that ether interface can also be TOD (Time of Day, Time of Day) interface, individually below with ether interface and
It is further to being carried out according to the deviation update synchronizing information that downstream equipment is sent of the characterization time for TOD interfaces
Ground explanation.
1, the master port that downstream equipment sends synchronizing information is ether interface
The master port that synchronizing information is sent to downstream equipment is ether interface, synchronizing information at this time be exactly the time it is same
Walk message.
It first checks for the sending mode for the port that the synchronizing information is sent to upstream device being single-step mode or double
Step mode.
1) single-step mode
If it is single-step mode to check the sending mode for the port that the synchronizing information is sent to upstream device, by Sync
When message is sent to upstream device, the Offset is added to the Sync messages.
When specifically, by Sync messages are sent, the current gate time of counter corresponding with threshold register is reset is made
For initial first time stamp t1 nanosecond value, while using internal system preserve the TOD times as the seconds value of the first time stamp t2, together
When, judge whether be less than 1 second according to the calculated Offset of step 301, when Offset is greater than or equal to 1 second, illustrates to be counted
The Offset of calculation has the deviation on the second, in this case, it is usually because the deviation caused by deviation is not converged is unstable, then not
Update the Correction Field fields of the Sync messages.When Offset is less than 1 second, (deviation more than seconds value is
Zero) the Correction Field fields that the Sync messages, are updated using the Offset less than 1 second, are sent to upstream device.
Wherein, Correction Field fields include sign bit, which is positive number or negative for characterizing the Offset,
If the calculated Offset of institute is -1058ns in step 301, then the sign bit of the Correction Field fields is then set
"-".Upstream device is after receiving the Sync messages, by the first original time stamp t1 combinations Correction of Sync messages
Offset in Field fields is modified to obtain actual first time stamp t1.
After downstream equipment sends Sync messages, the Delay_Req messages of upstream device transmission can be received, it should
Delay_Req messages receive the time stamp of the Delay_Req messages for upstream device to local device request local device.
It is corresponding with threshold register is reset when by receiving Delay_Req messages after receiving the Delay_Req messages
Nanosecond value of the current gate time of counter as the 6th time stamp t6, using the TOD times preserved inside current system as
The seconds value of 6th time stamp t6, and 301 calculated Offset of checking step is positive number or negative, it, then will be described if positive number
The nanosecond value of 6th time stamp is added with the nanosecond value of the Offset, and judges whether numerical value after being added needs carry, i.e. phase
Whether the numerical value after adding is more than 1 second, if so, using the remainder obtained after the magnitude carry as updated 6th time stamp
The nanosecond value of (being equivalent to the 4th time stamp t4 when downstream equipment sends Delay_Req messages), using the seconds value after carry as
The seconds value of updated 6th time stamp (seconds value of the 6th time stamp is added to the seconds value after 1 as updated 6th time stamp)；If
Numerical value after being added does not need carry, i.e., numerical value after being added be no more than 1 second, then will the numerical value after being added as described in more
The nanosecond value of the 6th time stamp after new, the other values of the 6th time stamp are still constant.
If the Offset is negative, it is greater than or equal to the nanosecond value of the Offset in the nanosecond value of the 6th time stamp
When, then using the nanosecond value of the 6th time stamp subtract the Offset nanosecond value absolute value as described updated
The nanosecond value of six time stamps, the other values of the 6th time stamp are still constant；It is less than the Offset's in the nanosecond value of the 6th time stamp
Nanosecond value absolute value when, by the 6th time stamp nanosecond value plus after 1 second, then subtract the Offset nanosecond value it is exhausted
To be worth subtracted 1 second to get the seconds value to the nanosecond value of updated 6th time stamp, the 6th time stamp after obtain numerical value, as update
The seconds value of the 6th time stamp afterwards.After obtaining updated 6th time stamp, which is added to described
In Delay_Req messages so that be added to updated 6th time stamp nanosecond value and seconds value Delay_Req messages
It is sent to upstream device as the synchronizing information.
2) two-step pattern
If it is two-step pattern to check the sending mode for the port that the synchronizing information is sent to upstream device, downstream
The 5th time stamp t5 when sending Sync messages will not be then carried in the Sync messages that equipment is sent (with the angle of upstream device to come
See, the 5th time stamp t5 be send Sync messages the first time stamp t1), then can by send Sync messages when the 5th time stamp
After t5 is updated according to calculated offset, updated 5th time stamp t5 is added in Follow_Up messages and is sent to down
Swim equipment.
Specifically, after obtaining the 5th time stamp t5 when sending Sync messages, 301 calculated Offset of checking step is
The nanosecond value of 5th time stamp is then added with the nanosecond value of the Offset, and judge by positive number or negative if positive number
Whether numerical value after being added needs carry, i.e., whether numerical value after being added is more than 1 second, if so, by being obtained after the magnitude carry
Nanosecond value of the remainder arrived as updated 5th time stamp (downstream the first time stamp t1 when equipment transmission Sync messages), will
Seconds value after carry as updated 5th time stamp seconds value (as updated the after the seconds value of the 5th time stamp is added 1
The seconds value of five time stamps)；If numerical value after being added does not need carry, i.e., numerical value after being added is no more than 1 second, then will be after the addition
Nanosecond value of the numerical value as updated 5th time stamp, the other values of the 5th time stamp are still constant.
If the Offset is negative, it is greater than or equal to the nanosecond value of the Offset in the nanosecond value of the 5th time stamp
When, then using the nanosecond value of the 5th time stamp subtract the Offset nanosecond value absolute value as described updated
The nanosecond value of five time stamps, the other values of the 5th time stamp are still constant；It is less than the Offset's in the nanosecond value of the 5th time stamp
Nanosecond value absolute value when, by the 5th time stamp nanosecond value plus after 1 second, then subtract the Offset nanosecond value it is exhausted
To be worth subtracted 1 second to get the seconds value to the nanosecond value of updated 5th time stamp, the 5th time stamp after obtain numerical value, as update
The seconds value of the 5th time stamp afterwards.After obtaining updated 5th time stamp, which is added to described
In Follow_Up messages so that be added to updated 5th time stamp nanosecond value and seconds value Follow_Up messages
It is sent to upstream device as the synchronizing information.
After downstream equipment sends the Follow_Up messages with the 5th time stamp t5, upstream device hair can be received
The Delay_Req messages sent, which is equally used for upstream device, and to local device, (upstream of upstream device is set
It is standby) request local device receives the time stamps of the Delay_Req messages.
It is corresponding with threshold register is reset when by receiving Delay_Req messages after receiving the Delay_Req messages
Nanosecond value of the current gate time of counter as the 6th time stamp t6, using the TOD times preserved inside current system as
The seconds value of 6th time stamp t6, and 301 calculated Offset of checking step is positive number or negative, it, then will be described if positive number
The nanosecond value of 6th time stamp is added with the nanosecond value of the Offset, and judges whether numerical value after being added needs carry, i.e. phase
Whether the numerical value after adding is more than 1 second, if so, using the remainder obtained after the magnitude carry as updated 6th time stamp
The nanosecond value of (being equivalent to the 4th time stamp t4 when downstream equipment sends Delay_Req messages), using the seconds value after carry as
The seconds value of updated 6th time stamp (seconds value of the 6th time stamp is added to the seconds value after 1 as updated 6th time stamp)；If
Numerical value after being added does not need carry, i.e., numerical value after being added be no more than 1 second, then will the numerical value after being added as described in more
The nanosecond value of the 6th time stamp after new, the other values of the 6th time stamp are still constant.
If the Offset is negative, it is greater than or equal to the nanosecond value of the Offset in the nanosecond value of the 6th time stamp
When, then using the nanosecond value of the 6th time stamp subtract the Offset nanosecond value absolute value as described updated
The nanosecond value of six time stamps, the other values of the 6th time stamp are still constant；It is less than the Offset's in the nanosecond value of the 6th time stamp
Nanosecond value absolute value when, by the 6th time stamp nanosecond value plus after 1 second, then subtract the Offset nanosecond value it is exhausted
To be worth to get the seconds value to the nanosecond value of updated 6th time stamp, the 6th time stamp subtract 1 second it is described after obtain numerical value, as
The seconds value of updated 6th time stamp.After obtaining updated 6th time stamp, which is added to institute
State in Delay_Req messages so that be added to updated 6th time stamp nanosecond value and seconds value Delay_Req report
Text is sent to upstream device as the synchronizing information.
So, the port that no matter downstream equipment sends synchronizing information is single-step mode or two-step pattern,
Ensure the time consistency of the time and upstream and downstream equipment of local device output.
2, downstream equipment the master port of synchronizing information will be sent as TOD interfaces
The master port that synchronizing information is sent to downstream equipment is TOD interfaces, and the synchronizing information includes pulse per second (PPS) letter
Number and TOD information.
Specifically, can be by pre-setting counter, and count duration in counter and reach when being worth nanosecond of Offset,
Downstream equipment sends 1PPS (pps pulse per second signal) to ensure the time synchronization between upstream device and local device.It is local to ensure
The timing time of equipment is more accurate, and the synchronised clock that can restore in the clock module of local device is supplied to local device
After FPGA (Field-Programmable Gate Array, programmable logic device), clock module is restored by FPGA
Synchronised clock frequency multiplication is to 250Mhz or 500Mhz, and the synchronised clock that finally uses that treated is as counter.
If judging the Offset preserved in the corresponding register of PHY chip for positive number, sent receiving internal PHY chip
1PPS when, open counter, when the gate time of the counter reaches the nanosecond value of the Offset, downstream equipment
1PPS is sent, and TOD information will be assembled into the seconds value for the time for receiving 1PPS, is arrived after downstream equipment sends 1PPS
Up to after preset time, the TOD information after assembling is exported by TOD interfaces to upstream device；
If judging the Offset preserved in the corresponding register of PHY chip for negative, in the 1PPS for receiving PHY chip
When, counter is opened, when the gate time of the counter reaches 1 second and subtracts the time obtained after the Offset, downwards
It swims equipment and sends 1PPS.1 second seconds value as current time will be added in the seconds value for receiving the time that PHY chip sends 1PPS
It is assembled into TOD information, when reaching preset time after downstream equipment sends 1PPS, the TOD information after assembling is connect by TOD
Mouth is exported to upstream device.It as a result, in embodiments of the present invention, can be using the 1PPS and the TOD information of assembling as update
Synchronizing information afterwards is sent to upstream device.Upstream device is after receiving the synchronizing information, you can according to the TOD of upstream equipment
Time second assembled in 1PPS the and TOD information that interface is sent determines that upstream equipment sends time second of 1PPS, due to the second
Time be according to Offset updated times second, therefore can ensure local device output time second and upstream equipment second
Time consistency.
Referring to FIG. 5, PTP system method for synchronizing time provided by the invention, is calculating local device and upstream equipment
Offset after, make the time of local device and upstream equipment keep a constant deviation (time of such as upstream device is always
It is more late 1058ns than upstream equipment), when downstream equipment synchronizes local device into row clock, this constant difference is compensated
Fall, the time to ensure local device output is consistent with upstream equipment.
Fig. 6 is the structural schematic diagram of the PTP system time synchronism apparatus, which may include：
Acquiring unit 601 and updating unit 602.Wherein：
Acquiring unit 601, for according to the time stamp acquisition of the time synchronization message interacted with upstream equipment and upstream equipment
Characterize the deviation of time；
Updating unit 602, for downstream equipment to be sent according to the deviation update with the upstream equipment characterization time
Synchronizing information.
Further, the updating unit 602 in Fig. 6 specifically can be used for, if downstream equipment sends the end of synchronizing information
Mouthful sending mode be single-step mode, then judge whether the deviation with the upstream equipment characterization time is less than default value,
If so, the deviation for characterizing the time with upstream equipment is added in the Sync messages, it is sent to upstream device.
Further, the updating unit 602 in Fig. 6 specifically can be used for, if downstream equipment sends the end of synchronizing information
The sending mode of mouth is two-step pattern, after sending Sync messages, obtains the 5th time stamp for sending the Sync messages；If sentencing
The deviation with the upstream equipment characterization time is positive number, by the 5th time stamp nanosecond value with described and upstream equipment
The nanosecond value for characterizing the deviation of time is added, and judge numerical value after being added whether need seconds value to the 5th time stamp into
Position, if so, using the remainder obtained after the carry as the nanosecond value of updated 5th time stamp, by after carry the 5th when
Seconds value of the seconds value of stamp as updated 5th time stamp, otherwise, using the numerical value after being added as described updated
The nanosecond value of five time stamps, using the seconds value of the 5th time stamp as the seconds value of updated 5th time stamp；If judge it is described with it is upper
The deviation of trip equipment characterization time is negative, is greater than or equal to described and upstream equipment table in the nanosecond value of the 5th time stamp
Levy the deviation of time nanosecond value absolute value when, subtracted using the nanosecond value of the 5th time stamp described with upstream equipment table
Levy the deviation of time nanosecond value nanosecond value of the absolute value as updated 5th time stamp, by the 5th time stamp
Seconds value of the seconds value as updated 5th time stamp；It is less than described and upstream equipment in the nanosecond value of the 5th time stamp to characterize
The deviation of time nanosecond value absolute value when, by the 5th time stamp nanosecond value plus subtracting within 1 second described and upstream again
Equipment characterize the deviation of time nanosecond value the nanosecond value for thoroughly deserving updated 5th time stamp, and by the described 5th
The seconds value of time stamp subtracts the seconds value for obtaining updated 5th time stamp for 1 second；By the nanosecond of updated 5th time stamp
Value and seconds value are added in the Follow_Up messages, are sent to upstream device.
Further, the updating unit 602 in Fig. 6 specifically can be used for, and when receiving pps pulse per second signal, opens and counts
Device；If the deviation of the characterization time with upstream equipment is positive number, the gate time of the counter reach it is described with it is upper
When swimming the nanosecond value of the deviation of equipment characterization time, downstream equipment sends pps pulse per second signal, and will receive pulse per second (PPS)
The seconds value of the time of signal is assembled into TOD information, after reaching preset time, the TOD information after assembling is defeated by TOD interfaces
Go out to upstream device；If the deviation of the characterization time is negative, reaches in the gate time of the counter and subtracted by 1 second
When the absolute value of the deviation for characterizing the time with upstream equipment, downstream equipment sends pps pulse per second signal, and will receive
Seconds value to the time of pps pulse per second signal was assembled into TOD information plus 1 second seconds value as current time, reached preset time
Afterwards, the TOD information after assembling is exported by TOD interfaces to upstream device.
Further, the time synchronization message interacted with upstream equipment includes the Sync reports sent by upstream equipment
Text receives the Sync messages that upstream equipment is sent referring to FIG. 6, described device can also include time stamp acquiring unit 603；If
The port that the upstream equipment sends the Sync messages is single-step mode, obtains initial first carried in the Sync messages
Time stamp；Check whether the specific field in the Sync messages is default value, if so, using initial first time stamp as first
Time stamp t1；If it is not, the numerical value of initial first time stamp t1 combination specific fields is modified, and obtain the first time stamp t1.
Further, time stamp acquiring unit 603 shown in fig. 6 can be also used for, in the Sync for receiving upstream equipment transmission
After message, if the port that the upstream equipment sends the Sync messages is two-step pattern, upstream equipment transmission is being received
When Follow_Up messages, the first time stamp t1 carried in the Follow_Up messages is obtained.
Further, the synchronizing information can also include Delay_Resp messages, and the updating unit 602 specifically can be with
For：
After downstream equipment sends Sync messages or Follow_Up messages, if receiving the delay of upstream device transmission
Delay_Req messages are asked, when by receiving Delay_Req messages, the current meter of counter corresponding with threshold register is reset
Nanosecond value of the number time as the 6th time stamp t6, using the TOD times preserved inside current system as the seconds value of the 6th time stamp t6；
If checking, the deviation with the upstream equipment characterization time is positive number, by the 6th time stamp nanosecond value with the Offset
Nanosecond value be added, and judge whether numerical value after being added needs carry, if so, using the remainder obtained after carry as updating after
The 6th time stamp nanosecond value, using the seconds value after carry as the seconds value of updated 6th time stamp；It otherwise, will be after the addition
Nanosecond value of the numerical value as updated 6th time stamp, when using the seconds value of the 6th time stamp as the updated 6th
The seconds value of stamp；If the deviation for characterizing the time described in judging with upstream equipment is negative, big in the nanosecond value of the 6th time stamp
In or equal to the characterization time with upstream equipment deviation nanosecond value absolute value when, use receiving for the 6th time stamp
Seconds value subtract it is described with the deviation of upstream equipment characterization time nanosecond value absolute value as the described updated 6th when
The nanosecond value of stamp, using the seconds value of the 6th time stamp as the seconds value of updated 6th time stamp；In receiving for the 6th time stamp
Seconds value be less than it is described with the deviation of upstream equipment characterization time nanosecond value absolute value when, by the nanosecond of the 6th time stamp
Value thoroughly deserves the updated 6th plus the nanosecond value with the deviation of upstream equipment characterization time is subtracted within 1 second again
The nanosecond value of time stamp, and the seconds value of the 6th time stamp is subtracted to the seconds value for obtaining updated 6th time stamp for 1 second；By institute
State updated 6th time stamp nanosecond value and seconds value be added in the Delay_Resp messages, be sent to upstream device.
Further, the time synchronization message interacted with upstream equipment can also include what upstream device was sent
Delay_Req messages and the Delay_Resp messages sent by upstream equipment, referring to FIG. 6, described device can also include
Setting unit 604, for the corresponding numerical value for resetting threshold register in the port for receiving the Sync messages to be set as fixed
Numerical value will be described when so that the counting duration of counter corresponding with the clearing threshold register reaching the fixed numbers
The counting of counter resets New count of laying equal stress on；The time stamp acquiring unit 603 can be also used for, and receive the Sync messages
When, using the current gate time of the counter as the nanosecond value of the second time stamp t2, TOD times that inside is preserved are as the
The seconds value of two time stamp t2；Upstream device sends Delay_Req messages, counter when by transmission Delay_Req messages
Nanosecond value of the gate time as third time stamp t3, the TOD times that inside is preserved are as the seconds value of third time stamp t3；In reception
The Delay_Resp messages that equipment is sent are swum, the 4th time stamp t4 that upstream equipment receives the Delay_Req messages is obtained；Institute
State the deviation for the characterization time that acquiring unit described in acquiring unit 601 is specifically used for through the calculating of following formula and upstream equipment
Value：With deviation=(t2-t1)-[ of the characterization time of upstream equipment;(t2–t1)+(t4–t3)]/2.
Above-mentioned apparatus can also be realized, with soft by software realization by way of hardware or software and hardware combining
For the mode of combination of hardware, referring to FIG. 7, for the hardware frame of PTP system time synchronism apparatus of the present invention place local device
Structure schematic diagram, basic hardware environment include other hardware such as CPU, memory and FPGA, and wherein memory includes machine
Readable instruction, CPU read and execute the function that machine readable instructions combination FPGA executes each unit in Fig. 6.
As can be seen that the present invention is calculated according to the message time stamp of acquisition from the embodiment of any of the above method and apparatus
Go out with after the deviation of the characterization time of upstream equipment, make the time of local device and upstream equipment keep one it is constant inclined
Difference is fallen this constant difference compensation, when downstream equipment carries out time synchronization to local device to ensure PTP system
Characterization time synchronization between middle and upper reaches equipment and upstream device.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the invention, all essences in the present invention
With within principle, any modification, equivalent substitution, improvement and etc. done should be included within the scope of protection of the invention god.
Claims (14)
1. a kind of Precision Time Protocol PTP system method for synchronizing time, which is characterized in that the method includes：
The deviation that the time is characterized with upstream equipment is obtained according to the time stamp of the time synchronization message interacted with upstream equipment；
According to the deviation update synchronizing information that downstream equipment is sent for characterizing the time with upstream equipment；
Wherein, the synchronizing information includes synchronous Sync messages, and the deviation that the basis characterizes the time with upstream equipment updates
The synchronizing information that downstream equipment is sent specifically includes：
If the sending mode that downstream equipment sends the port of synchronizing information is single-step mode, described and upstream equipment table is judged
Whether the deviation for levying the time is less than 1 second, if so, the deviation for characterizing the time with upstream equipment is added to the Sync
In message, it is sent to upstream device.
2. the method as described in claim 1, which is characterized in that the synchronizing information includes Sync messages and follows Follow_
Up messages, the deviation update synchronizing information that downstream equipment is sent that the basis characterizes the time with upstream equipment are specifically wrapped
It includes：
If the sending mode that downstream equipment sends the port of synchronizing information is two-step pattern,
After sending Sync messages, the 5th time stamp for sending the Sync messages is obtained；
If judging, the deviation with the upstream equipment characterization time is positive number, by the 5th time stamp nanosecond value with it is described and
The nanosecond value that upstream equipment characterizes the deviation of time is added, and judges whether numerical value after being added needs to the 5th time stamp
Seconds value carry, if so, using the remainder obtained after the carry as the nanosecond value of updated 5th time stamp, after carry
The 5th time stamp seconds value of the seconds value as updated 5th time stamp, otherwise, using the numerical value after being added as it is described more
The nanosecond value of the 5th time stamp after new, using the seconds value of the 5th time stamp as the seconds value of updated 5th time stamp；
If judging, the deviation of described and upstream equipment characterization time as negative, is more than or waits in the nanosecond value of the 5th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value using the 5th time stamp subtracts
Go it is described with the deviation of upstream equipment characterization time nanosecond value absolute value receiving as updated 5th time stamp
Seconds value, using the seconds value of the 5th time stamp as the seconds value of updated 5th time stamp；It is small in the nanosecond value of the 5th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value of the 5th time stamp is added
The nanosecond value with the deviation of upstream equipment characterization time is subtracted within 1 second again thoroughly deserves updated 5th time stamp
Nanosecond value, and the seconds value of the 5th time stamp is subtracted to the seconds value for obtaining updated 5th time stamp for 1 second；
By updated 5th time stamp nanosecond value and seconds value be added in the Follow_Up messages, be sent to down
Swim equipment.
3. method as claimed in claim 2, which is characterized in that the synchronizing information further includes that Delay_Resp reports are responded in delay
Text, the deviation update synchronizing information that downstream equipment is sent that the basis characterizes the time with upstream equipment specifically include：
After downstream equipment sends Sync messages or Follow_Up messages, if receiving the latency request of upstream device transmission
Delay_Req messages, when by receiving Delay_Req messages, when with resetting the current counting of the corresponding counter of threshold register
Between nanosecond value as the 6th time stamp t6, using the TOD times preserved inside current system as the seconds value of the 6th time stamp t6；
If checking, the deviation with the upstream equipment characterization time is positive number, by the 6th time stamp nanosecond value with it is described
The nanosecond value of Offset is added, and judges whether numerical value after being added needs carry, if so, using the remainder obtained after carry as
The nanosecond value of updated 6th time stamp, using the seconds value after carry as the seconds value of updated 6th time stamp；It otherwise, will be described
Nanosecond value of the numerical value after being added as updated 6th time stamp, using the seconds value of the 6th time stamp as updated
The seconds value of 6th time stamp；
If judging, the deviation of described and upstream equipment characterization time as negative, is more than or waits in the nanosecond value of the 6th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value using the 6th time stamp subtracts
Go it is described with the deviation of upstream equipment characterization time nanosecond value absolute value receiving as updated 6th time stamp
Seconds value, using the seconds value of the 6th time stamp as the seconds value of updated 6th time stamp；It is small in the nanosecond value of the 6th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value of the 6th time stamp is added
The nanosecond value with the deviation of upstream equipment characterization time is subtracted within 1 second again thoroughly deserves updated 6th time stamp
Nanosecond value, and the seconds value of the 6th time stamp is subtracted to the seconds value for obtaining updated 6th time stamp for 1 second；
By updated 6th time stamp nanosecond value and seconds value be added in the Delay_Resp messages, be sent to down
Swim equipment.
4. the method as described in claim 1, which is characterized in that the synchronizing information includes pps pulse per second signal and TOD information, institute
It states and is specifically included according to the deviation update synchronizing information that downstream equipment is sent for characterizing the time with upstream equipment：
When receiving pps pulse per second signal, counter is opened；
If the deviation of the characterization time with upstream equipment is positive number, the gate time of the counter reach it is described with it is upper
When swimming the nanosecond value of the deviation of equipment characterization time, downstream equipment sends pps pulse per second signal, and will receive pulse per second (PPS)
The seconds value of the time of signal is assembled into TOD information, after reaching preset time, the TOD information after assembling is defeated by TOD interfaces
Go out to upstream device；
If the deviation of the characterization time is negative, the gate time of the counter reach by subtract within 1 second it is described with it is upper
When swimming the absolute value of the deviation of equipment characterization time, downstream equipment sends pps pulse per second signal, and will receive pulse per second (PPS)
The seconds value of the time of signal was assembled into TOD information plus 1 second seconds value as current time, after reaching preset time, by group
TOD information after dress is exported by TOD interfaces to upstream device.
5. the method as described in claim 1, which is characterized in that the time synchronization message interacted with upstream equipment include by
The Sync messages that upstream equipment is sent, the method further include：
Receive the Sync messages that upstream equipment is sent；
If the upstream equipment send the Sync messages port be single-step mode, obtain carried in the Sync messages just
Begin the first time stamp；
Check whether the specific field in the Sync messages is default value, if so, using initial first time stamp as first
Time stamp t1；If it is not, the numerical value of initial first time stamp t1 combination specific fields is modified, and obtain the first time stamp t1.
6. method as claimed in claim 5, which is characterized in that after receiving the Sync messages that upstream equipment is sent, if described
The port that upstream equipment sends the Sync messages is two-step pattern, in the Follow_Up messages for receiving upstream equipment transmission
When, obtain the first time stamp t1 carried in the Follow_Up messages.
7. such as method described in claim 5 or 6, which is characterized in that the time synchronization message package interacted with upstream equipment
The Delay_Resp messages for including the Delay_Req messages of upstream device transmission and being sent by upstream equipment, the method is also
Including：
By the port for receiving the Sync messages it is corresponding reset threshold register numerical value be set as fixed numbers, for
When the counting duration for resetting the corresponding counter of threshold register reaches the fixed numbers, by the counting of the counter
Clearing is laid equal stress on New count；
It, will using the current gate time of the counter as the nanosecond value of the second time stamp t2 when receiving the Sync messages
Seconds value of the current Time of Day TOD times that inside preserves as the second time stamp t2；
Upstream device sends Delay_Req messages, using the gate time of counter when sending Delay_Req messages as
The nanosecond value of third time stamp t3, the TOD times that inside is preserved are as the seconds value of third time stamp t3；
The Delay_Resp messages that upstream equipment is sent are received, upstream equipment is obtained and receives the of the Delay_Req messages
Four time stamp t4；
The time stamp of the basis and the time synchronization message of upstream equipment interaction obtains and the deviation of the characterization time of upstream equipment
Value specifically includes the deviation calculated by following formula with the characterization time of upstream equipment：
With deviation=(t2-t1)-[ of the characterization time of upstream equipment;(t2–t1)+(t4–t3)]/2.
8. a kind of PTP system time synchronism apparatus, which is characterized in that described device includes：
Acquiring unit characterizes the time for being obtained according to the time stamp of the time synchronization message interacted with upstream equipment with upstream equipment
Deviation；
Updating unit, for according to the deviation update synchronous letter that downstream equipment is sent for characterizing the time with upstream equipment
Breath；
Wherein, the synchronizing information includes synchronous Sync messages, and the updating unit is specifically used for：
If the sending mode that downstream equipment sends the port of synchronizing information is single-step mode, described and upstream equipment table is judged
Whether the deviation for levying the time is less than 1 second, if so, the deviation for characterizing the time with upstream equipment is added to the Sync
In message, it is sent to upstream device.
9. device as claimed in claim 8, which is characterized in that the synchronizing information includes Sync messages and follows Follow_
Up messages, the updating unit are specifically used for：
If the sending mode that downstream equipment sends the port of synchronizing information is two-step pattern,
After sending Sync messages, the 5th time stamp for sending the Sync messages is obtained；
If judging, the deviation with the upstream equipment characterization time is positive number, by the 5th time stamp nanosecond value with it is described and
The nanosecond value that upstream equipment characterizes the deviation of time is added, and judges whether numerical value after being added needs to the 5th time stamp
Seconds value carry, if so, using the remainder obtained after the carry as the nanosecond value of updated 5th time stamp, after carry
The 5th time stamp seconds value of the seconds value as updated 5th time stamp, otherwise, using the numerical value after being added as it is described more
The nanosecond value of the 5th time stamp after new, using the seconds value of the 5th time stamp as the seconds value of updated 5th time stamp；
If judging, the deviation of described and upstream equipment characterization time as negative, is more than or waits in the nanosecond value of the 5th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value using the 5th time stamp subtracts
Go it is described with the deviation of upstream equipment characterization time nanosecond value absolute value receiving as updated 5th time stamp
Seconds value, using the seconds value of the 5th time stamp as the seconds value of updated 5th time stamp；It is small in the nanosecond value of the 5th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value of the 5th time stamp is added
The nanosecond value with the deviation of upstream equipment characterization time is subtracted within 1 second again thoroughly deserves updated 5th time stamp
Nanosecond value, and the seconds value of the 5th time stamp is subtracted to the seconds value for obtaining updated 5th time stamp for 1 second；
By updated 5th time stamp nanosecond value and seconds value be added in the Follow_Up messages, be sent to down
Swim equipment.
10. device as claimed in claim 9, which is characterized in that the synchronizing information further includes Delay_Resp messages, described
Updating unit is specifically used for：
After downstream equipment sends Sync messages or Follow_Up messages, if receiving the latency request of upstream device transmission
Delay_Req messages, when by receiving Delay_Req messages, when with resetting the current counting of the corresponding counter of threshold register
Between nanosecond value as the 6th time stamp t6, using the TOD times preserved inside current system as the seconds value of the 6th time stamp t6；
If checking, the deviation with the upstream equipment characterization time is positive number, by the 6th time stamp nanosecond value with it is described
The nanosecond value of Offset is added, and judges whether numerical value after being added needs carry, if so, using the remainder obtained after carry as
The nanosecond value of updated 6th time stamp, using the seconds value after carry as the seconds value of updated 6th time stamp；It otherwise, will be described
Nanosecond value of the numerical value after being added as updated 6th time stamp, using the seconds value of the 6th time stamp as updated
The seconds value of 6th time stamp；
If judging, the deviation of described and upstream equipment characterization time as negative, is more than or waits in the nanosecond value of the 6th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value using the 6th time stamp subtracts
Go it is described with the deviation of upstream equipment characterization time nanosecond value absolute value receiving as updated 6th time stamp
Seconds value, using the seconds value of the 6th time stamp as the seconds value of updated 6th time stamp；It is small in the nanosecond value of the 6th time stamp
In the deviation that the time is characterized with upstream equipment nanosecond value absolute value when, the nanosecond value of the 6th time stamp is added
The nanosecond value with the deviation of upstream equipment characterization time is subtracted within 1 second again thoroughly deserves updated 6th time stamp
Nanosecond value, and the seconds value of the 6th time stamp is subtracted to the seconds value for obtaining updated 6th time stamp for 1 second；
By updated 6th time stamp nanosecond value and seconds value be added in the Delay_Resp messages, be sent to down
Swim equipment.
11. device as claimed in claim 8, which is characterized in that the synchronizing information includes pps pulse per second signal and TOD information,
The updating unit is specifically used for：
When receiving pps pulse per second signal, counter is opened；
If the deviation of the characterization time with upstream equipment is positive number, the gate time of the counter reach it is described with it is upper
When swimming the nanosecond value of the deviation of equipment characterization time, downstream equipment sends pps pulse per second signal, and will receive pulse per second (PPS)
The seconds value of the time of signal is assembled into TOD information, after reaching preset time, the TOD information after assembling is defeated by TOD interfaces
Go out to upstream device；
If the deviation of the characterization time is negative, the gate time of the counter reach by subtract within 1 second it is described with it is upper
When swimming the absolute value of the deviation of equipment characterization time, downstream equipment sends pps pulse per second signal, and will receive pulse per second (PPS)
The seconds value of the time of signal was assembled into TOD information plus 1 second seconds value as current time, after reaching preset time, by group
TOD information after dress is exported by TOD interfaces to upstream device.
12. device as claimed in claim 8, which is characterized in that the time synchronization message interacted with upstream equipment includes
The Sync messages sent by upstream equipment, described device further include：
Time stamp acquiring unit receives the Sync messages that upstream equipment is sent；If the upstream equipment sends the Sync messages
Port is single-step mode, obtains initial first time stamp carried in the Sync messages；It checks specified in the Sync messages
Whether field is default value, if so, using initial first time stamp as the first time stamp t1；If it is not, by initial first time stamp t1
It is modified in conjunction with the numerical value of specific field, and obtains the first time stamp t1.
13. device as claimed in claim 12, which is characterized in that the time stamp acquiring unit is additionally operable to：
After receiving the Sync messages that upstream equipment is sent, if the port that the upstream equipment sends the Sync messages is two-step
Pattern obtains first carried in the Follow_Up messages when receiving the Follow_Up messages of upstream equipment transmission
Time stamp t1.
14. device as described in claim 12 or 13, which is characterized in that the time synchronization message interacted with upstream equipment
The Delay_Req messages sent including upstream device and the Delay_Resp messages sent by upstream equipment, described device
Further include：
Setting unit, for the corresponding numerical value for resetting threshold register in the port for receiving the Sync messages to be set as fixed
Numerical value will be described when so that the counting duration of counter corresponding with the clearing threshold register reaching the fixed numbers
The counting of counter resets New count of laying equal stress on；
The time stamp acquiring unit is additionally operable to：
It, will using the current gate time of the counter as the nanosecond value of the second time stamp t2 when receiving the Sync messages
Seconds value of the TOD times that inside preserves as the second time stamp t2；Upstream device sends Delay_Req messages, will send
Nanosecond value of the gate time of the counter as third time stamp t3 when Delay_Req messages, the TOD times that inside is preserved
Seconds value as third time stamp t3；The Delay_Resp messages that upstream equipment is sent are received, acquisition upstream equipment receives described
4th time stamp t4 of Delay_Req messages；
The acquiring unit is specifically used for calculating the deviation with the characterization time of upstream equipment by following formula：
With deviation=(t2-t1)-[ of the characterization time of upstream equipment;(t2–t1)+(t4–t3)]/2.
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| CN105357752B (en) * | 2015-12-07 | 2018-11-02 | 北京邮电大学 | Method for synchronizing time and device for wireless self-networking |
| CN107528654B (en) * | 2016-06-21 | 2020-06-05 | 中兴通讯股份有限公司 | 1588-based time synchronization method and device |
| CN109327273B (en) * | 2018-01-02 | 2021-03-05 | 中国移动通信有限公司研究院 | Synchronization information transmission method, synchronization method, network node and storage medium |
| JP7235166B2 (en) | 2020-03-30 | 2023-03-08 | 日本電気株式会社 | Base station, communication system, communication method, and program |
| CN114079557B (en) * | 2020-08-19 | 2024-04-23 | 智邦科技股份有限公司 | Network device |
| CN114727377A (en) * | 2021-01-04 | 2022-07-08 | 中国移动通信有限公司研究院 | Synchronization method, synchronization device, time server and downstream time server |
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