QSIG Reliability

[Bucky101]

Gday,
I have 2 BCM 400s connected to each other via QSIG. BCM 1 has 2 PRI cards, one for the QSIG and 1 for the ISDN lines. BCM 2 has 1 PRI Card for the QSIG.
All incoming calls come in via BCM 1 and route to BCM 2 if necessary. I have set this kind of setup on many sites but this site has problems. Occasionally the QSIG link becomes dodgy and start losing calls for apparently no reason. This usually happens when a high volume of calls come into BCM 2 and the only way to fix is to cold reboot BCM 2. Hard to explain the setup but its just simple cascading of a BCM. Any ideas why it seems to work perfectly for a month and then just start to fail?

 

[TLDuk]

Im my experience of these kind of setups issues like this are mainly caused by isdn clocking problems..

the correct way to set two pbxs link together via qsig would be like below, "C" indicating where the PBX is getting its clocking source from

(PBX A)---QSIG---(PBX B)
: :
c c
: :
PRI PRI

In your configuration it would need to be configured like below, so PBX-B would take the clocking source from PBX-A so PBX B is nicely synchronized with A

(PBX A)---QSIG-c-(PBX B)
:
c
:
PRI

Of course make sure your system if fully patched up and they are both running identical s/w versions

 

[Bucky101]

Thanks TLDuk,
That is some great information. My clocking source setup is
PBX A - ISDN = Primary
PBX A - QSIG = Master (QSIG:Network Master)

PBX B - QSIG = Primary (QSIG:User Slave)

I do think that the Telcos clocking is responsible for messing up the clocking at the QSIG only dies when the call volume starts to max out. Let us know if there is something wrong with the above clocking setup.

The systems are 2x 4.0s with identical patches...having said that i dont think Nortel patches have done anything to QSIG for a while.

 

[TLDuk]

Nothing wrong there looks good to me...

if i think of anything i will get back to you

 

[Bucky101]

yeah thought so. Am i right in thinking that even with this setup the qsig is still relying on the isdn clock and could be failing because of the telco?

 

[TLDuk]

Yes there are many different ways to provide end to end qsig connections but they all still rely on a good clocking source to work correctly..