NTP via BITS on ASR9010

[pstebner10]

Has anyone ever done this? I see that v4.3.0 has added NTP-PTP interworking and I thought that this would be possible, but the documentation is pretty scarce.

Basically, we have a GPS clock providing BITS timing via the SYNC0 port on 0/RSP0/CPU0, and we want to be able to run the ASR as a master NTP server based off of this. Any ideas?

thanks in advance,

Paul

[xthuijs]

SyncE is synchronous ethernet, meaning that the TX clock for the ethernet is taken from a common source so that 2 interfaces effectively clock their bits out at the exact same pace.

BITS is build in integrated timing system. It is used as a source to pull in a clock from a low stratum source that you want to use as TX clock for eg SONET/SDH or SYNC-E for that matter.

Also if there is a particular interface that receives a low stratum clock that you want to use, you can sync the timing system to that clock, eg from SDH/SONET networks (which are known to have great clock quality) and use that as system timing for eg export to BITS or clock distribution to SYNC-E/ethernet ports.

regards

xander

[manuv1984]

Hi Xander,

                     What I understood from your words is "BITS is an external time source for distributing time to low stratum (may be the clock module/board in the router at brach offices) source which provides the quality clock signals to the SynkE. May I know  what I understood is right?. If so can I know the use of the command "clock-interface timing-mode independent| system " in the router. Please do the needful.

[xthuijs]

Your understanding is correct. BITS is a timing source that you can use to pull in an accurate clock that in turn can be used for SYNC-E.

Config example:

clock-interface sync 0 location 0/RSP0/CPU0
 port-parameters
  bits-input e1 crc-4 sa4 hdb3
 !
 frequency synchronization
  selection input
  priority 1
  wait-to-restore 0
 !

frequency synchronization
 quality itu-t option 1
 log selection errors

RP/0/RSP0/CPU0:ariad#sh frequency synchronization clock-interfaces
Wed Mar 20 12:38:50.252 CET
Node 0/RSP0/CPU0:
==============
  Clock interface Sync0 (Up - BITS E1)
    Assigned as input for selection
    Wait-to-restore time 0 minutes
    SSM supported and enabled
    Input:
      Up
      Last received QL: Opt-I/PRC
      Effective QL: Opt-I/PRC, Priority: 1, Time-of-day Priority 100
      Supports frequency
    Output is disabled
  Next selection points: T0-SEL-B

[manuv1984]

Hi Xander,

     Can you please suggest any good documents which describes the 

detailed funstioning of sync E (eg: how it is sending SSM and  initiating 

signaling ) and PTP. I have already searched about it but every documents

mentioning only sync E is using SSM via ESMC as SSM in sonet/sdh, but nobody 

saying how sync E is sending and processing SSM (step by step) . Please do 

the needful. This is my humble request.

[xthuijs]

Ok, I did the needful and I got you this doc together:

https://supportforums.cisco.com/docs/DOC-31582

If you need further follow up on sync stuff, you may want to open a TAC case or contact your account team.

regards

xander