ASR1006 channelized OC3 and BITs reference

Unanswered Question
Feb 4th, 2010

We're moving to ASR and OC3s instead of 7200VXR with DS3s.  I have a question about the BITs ports on the RPs.  I have BITs connections, but I also know that the internal BITs clock is stratum III and our BITs clock is stratum I or II.

How do I configure the chassis to reference those BITs interfaces and when setting the OC3/DS3/T1 to line or internal, does internal fully use the BITs as a reference?

I have this problem too.
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Giuseppe Larosa Thu, 02/04/2010 - 13:38

Hello Tmarlow,

these clocking aspects are not mentioned in the SPA configuration guide:

feature navigator doesn't mention ASR 1000 among the supported platforms

search by feature : BITS lists only GSR 12000

However, ASR 1000 data sheet lists it:

Stratum-3 clock circuitry and BITS input ports

• Facilitates support of clocking for synchronous services such as SONET and SDH

Hope to help


tmarlow Fri, 02/05/2010 - 12:27

Hey Cisco,

There isn't very good documentation on this clocking topic and it is hard to understand how the ASR is going to use the BITs clock provided to the RP1s.  Look below and see, what is "Valid but not present" mean.  And if I type the below, am I using the internal BITs oscillator or the BITs port on the RP1?

I have this output after typing:

(config)#network-clock select 1 bits r0 t1 esf

(config)#network-clock select 2 bits r1 t1 esf

#show network-clocks
Active source = FREERUN

All Network Clock Configuration
Priority    Clock Source        State                         Reason
1           BITS R0 T1 esf      Valid but not present         No errs
2           BITS R1 T1 esf      Valid but not present         No errs

Current operating mode is Revertive

Current OOR Switchover mode is Switchover

There are no slots disabled from participating in network clocking

Giuseppe Larosa Sat, 02/06/2010 - 06:57

Hello TMarlow,

>> Active source = FREERUN

I would say it is using the internal clock

I would suggest you to open a Cisco TAC Service Request to get a feedback on the feature roadmap, it might be supported in a future IOS XE version for example.

Hope to help



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