PTN承载高精度时间同步协议技术研究英文文献资料

1、1 introductionin real application, the ptp protocol may need to be transported in different networks, for example, otn/wdm+ptn, ptn+pon.this contribution gives the test result of 1588v2 time synchronization in otn+ptn hybrid field trial network. the test result proves the possibility of using 1588v2

2、 to provide high precision time synchronization in otn+ptn network and the performance is similar to a single network with comparative scale. it is proposed that psn can be hybrid networks in the reference model.it is also proposed to start the research on 1588v2 over otn.2 field trial network confi

3、guration and test itemsin order to verify the 1588v2 time synchronization performance in hybrid networks, a field trial networks are launched. the trial network has 4 otn nodes, more than 23 td-scdma base stations and ptn nodes. figure 1 gives the configuration as follows:2.1 test configurationtest

4、network topology：its wits potnc otn aotnotn botn .ptnotu2i0geptnlotn d /rncptniob-4gexptn2aptn3ptn4<nodeb-ptn6time accptn5ptn7ptn9 ptn8xtiming path0hfigure 1: the field trial networktest configuration:1) all otn and ptn nodes are configured with bc mode. in ptn, the 1588v2 packets are terminated

5、in the ethernet ports and not encapsulated in lsp.2) the 1588v2 is encapsulated in oduk，as shown in figure 2. the timestamps are taken before the oduk goes into cross-connection.3) the fixed asymmetric delay of the fibres in two directions of transmission is compensated section by section in corresp

6、onding otn or ptn nodes.4) there are two time source equipments (bits) with gps/bd dual mode receivers in this hybrid network. the bits_w is connected with otn a through 1 pps+tod interface, the bits_p is connected with otn c through ge interface as the backup. the rnc is located at otn d and connec

7、t with otn equipment with ge interface. the interface between otn nodes is otu2, the interface between otn and ptn node is ge, and the interface between ptn node and nodeb is fe5) the otn+ptn hybrid network carries real voice and data services of the base stations and several fe leased line services

8、. each nodeb is connected to the ptn equipment through fe interface with 20mbps cir bandwidth assigned. vlan is used to identify the nodeb and different services within the nodeb are distinguished by priority.6) the nodebs get time synchronization either through fe interface or through an extra ipps

9、+tod interface and get frequency synchronization through synce.fassmgcco hotu resodu res. aodu t cm res.e acttcm6tcm5tcm4ftfltcm3tcm2tcm1pmexpgcc1gcc2aps/pcc/t588 odu j sync “ res. fodu res c odu res dfigure 2: 1588v2 encapsulation on otn2.2 test itemthe following items are tested: long term perform

10、ance time source equipment switch protection failure switch of otn ring failure switch of ptn ring2.3 test results2.2.1 long-term time variation performancethis test case is to observe the output time variations of a td-scdma station at ptn6 by a timeacc analyzer. the time and frequency synchronizat

11、ion link includes 4 otn nodes and 6 ptnnodes. the 1588v2 timing path is otnaotnbotncotnd->ptn 1 ptn2ptn3 ptn4ptn5ptn6node b. the td-scdma station gets time information from ptn ring by fe interface.when the nodeb gets time synchronization from ptn through fe interface, the time error is from 45ns

12、 to +38ns and the peak-to-peak time error is 83ns during 24 hours, as shown is figure 3. the mtie and tdev in figure 4 show that time synchronization performance is stable and the random noise is minor.(su) oajeu- buj.cursor a 0time (sec)cursor b: 89100measured signalmeasurement period : 89280notesu

13、plonded: 01-04-1998 sample interval : 2 secfigure 4: long term performance mtie and tdev in hybrid networkfigure 3: long term performance tie in hybrid network'wander analyst - otnbca. dat|x|elie communication upload plotprocess data helpit can be observed that using 1588v2 to provide high preci

14、sion time synchronization in otn+ptn hybrid network can meet the requirement of less than 1000ns.2.2.2 time source switch protectionin order to evaluate the effect of time source force switch protection on time synchronization performance, the following test is carried out, as shown in figure 5:1) t

15、he bits_w is connected with otn a through ipps+tod interface and bits_p is connected with otn c through 1588v2 ethernet interface. the test point is in the nodeb at ptn 6.2) the working time source is switched from bits_w to bits_p through disabling bits_w in the network management system.3) the swi

16、tch time is at 150s after the test beginning.4) the 1588v2 timing path before switching is bits_w->otna->otnb->otncotnd-> ptn1 -> ptn2-> ptn3 -> ptn4-> ptn5 -> ptn6-> node b after the switching the 1588v2 timing path is bits_p-* otnc-* otnd-*ptn 1 -> ptn2-* ptn3 ptn4

17、-*ptn5 -*ptn6 node b.ptn23ptn3ptn9 fin8otu2getiming pathtn6rrimc accptn70-figure 5: time source switch protection testthe time error is between +39ns+71ns with the peak-to-peak value of 32ns, as shown in figure 6.'wander analyst - bitsdha. mtielie communication upload plot maskhelp70.60-65.00-6u

18、55 0050 00-45.00-file communication upload plotprocess data helptimo (sec)cursor b: 225639 201000-00mtie ssu transientetsi 300 462 4(su)uj匚ziincursor a: 0notesmuasurud signal measurement period : 2264uploaded 01-0-1998 sample interval : 2 secfigure 6: tie and mtie for the switch of time source switc

19、h protection test1000 oo10000 00passednotesmeasured signal moasuromont poriod : zz6410 00timo (sec) 0 01mimt1e |uploaded 01-04-1998 sample interval : 2 sectdev 加沖 dnh223 failure switch of otn ringin order to evaluate the effect of otn ring switch protection on time synchronization performance, the f

20、ollowing test is carried out, as shown in figure 7:1) the bits_w is connected with otn a through ipps+tod interface and bits_p is connected with otn c through 1588v2 ethernet interface. the test point is in the nodeb at ptn 6.2) the time link is switched automatically under bmca from the working pat

21、h to the protection path by disabling the right 1588v2 port in otn a, as shown in figure 7.3) the switch time is at 680s after the test beginning.4) the 1588v2 timing path before switching is bits_w-*otna-*otnc->otnd->ptn 1 -* ptn2-ptn3-ptn4-ptn5-ptn6-node b. after the switching the 1588v2 tim

22、ing path is bits_w otna -> otnb otncotnd -> ptn 1 ptn2ptn3 ptn4 -> ptn5 ptn6-node b.its prncptn1otn d /ptn23-ptn3 "otnbptn10xptn4ptn9 ptn8xxotu2ptn ,10gegefigure 7:h-timing pathfailure switch of otn ringthe time error is between +45ns+80ns with the peak-to-peak value of 35ns, as shown

23、in figure 8.figure & tie and mtie for the switch of otn ring switch protection test224 time trail switch of ptn ringthe time link is switched automatically under bmca from the working path to the protection path by disabling the right 1588v2 port in ptn 6, as shown in figure 9.1) the bits_w is c

24、onnected with otn a through ipps+tod interface and bits_p is connected with otn c through 1588v2 ethernet interface. the test point is in the nodeb at ptn 6.2) the time link is switched automatically under bmca from the working path to the protection path by disabling the right 1588v2 port in ptn 6,

25、 as shown in figure 9.3) the switch time is at 40s after the test beginning.4) the 1588v2 timing path before switching is bits_w-otna-otnb-otnc-otnd- ptnio-ptn9-ptn8-ptn7-ptn6-node b. after the switching the 1588v2 timing path is bits_w -> otna -> otnb -* otnc -> otnd -* ptn 1 -* ptn2 ->

26、 ptn3 -* ptn4 -> ptn5-ptn6-node b.otn aotnotnbotn,ptnptnlpotn d /otncptn 10orncptn,otu21() gegefeptn2b-a-accptn7ptn9 ptn8timing pathptn4ptn5x>tn6figure 9: failure switch of ptn ringthe time error is between +43ns+85ns with the peak-to-peak value of 42ns, as shown in figure 10.'wander analyst - fptn-dha. dat-l|x| wander analyst - fptn-dha. mtielie communication upload plot