network-clock-participate & network-clock-select

Unanswered Question
Jun 3rd, 2009
User Badges:

Hi everyone,

Does anyone knows where I can find explanation of

the 'network-clock-participate' and 'network-clock-select' commands?

I have gone through multiple references, but I am still confused :-(

Thanks very much in advance.


  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (1 ratings)
Ayodeji Okanlawon Wed, 06/03/2009 - 23:22
User Badges:
  • Super Bronze, 10000 points or more
  • Cisco Designated VIP,

    2017 IP Telephony


To allow the ports on a specified network module or voice/WAN interface card (VWIC) to use the network clock for timing, use the network-clock-participate command in global configuration mode. To restrict the device to use only its own clock signals, use the no form of this command


To name a source to provide timing for the network clock and to specify the selection priority for this clock source, use the network-clock-select command in global configuration mode. To cancel the network clock selection, use the no form of this command.

Cisco 2600 Series and Cisco 3660 with MIX Module

network-clock-select priority {t1 | e1} slot/port

no network-clock-select priority {t1 | e1} slot/port

Nicholas Matthews Thu, 06/04/2009 - 04:36
User Badges:
  • Red, 2250 points or more

These commands exists on the ISRs to allow voice cards to access the TDM clock on the backplane. Since these cards don't have DSPs built in on them, they have to use the clock provided by the DSPs on the motherboard.

This is opposed to something like a T1 on an NM-HDV where the card has it's own DSPs and doesn't need to use the backplane clocking.

For VWICs plugged into the chassis they will not operate without network-clock-participate.

The TDM backplane can only do one clocking at a time, and the network-clock-select chooses which of the clocks it will sync with the TDM backplane.


balasundaram.k_2 Fri, 08/28/2009 - 05:02
User Badges:

Hi Nick,

Very clear explanations!!

Really very helpful!!!

Tx you very much!

+5 for you!!!




This Discussion