[cisco-voip] Clocking/slips issue with Nortel

[Andrius Kislas]

Hi,

I have a clocking / slips problem connecting Cisco 3845 to Nortel
CS1000M r4.5. The scenario is following:

Nortel is already connected to PSTN and is getting clock from network
(PSTN). Now I connect C3845 to Nortel using QSIG protocol and NM modules
NM-HDV2-2T1/E1. They ask me to be a network side and to provide
clocking. I do the following:

network-clock-participate slot 1
network-clock-participate slot 2

controller E1 1/0
 clock source internal
 pri-group timeslots 1-31
!
controller E1 1/1
 clock source internal
 pri-group timeslots 1-31
!
controller E1 2/0
 clock source internal
 pri-group timeslots 1-31


L2 us up, L3 is up (calls initiate) but unfortunately on both sides we
see slips. I don't get any clocking from line, so I cannot use
"network-clock-select". Here is one "show":
Router#sh network-clocks
  Network Clock Configuration
  ---------------------------
  Priority      Clock Source    Clock State     Clock Type
    11          Backplane       GOOD            PLL

  Current Primary Clock Source
  ---------------------------
  Priority      Clock Source    Clock State     Clock Type
    11          Backplane       GOOD            PLL

I have also tried to "no network-clock-participate slot 1 (and 2)" but
still the same - slips. Is there anything else I could do to correct
configuration and provide a proper clocking?
Am I right that best practice would be if Nortel would be a clocking
source as it gets clocking from PSTN?

Thanks for any comments,
Andrius