Hi, I have a problem with call forward failing between IP phones when called from outside the system. This appears to be only affecting the Call Forward All Function.
Call Manager 4.1(3) Sr3a connected directly to Siemens Realitis DX using an ISO Q.Sig compliant DLI card in the Siemens (MGCP controlled gateway on the CM). Siemens sits between CM and PSTN.
When calls come into the CCM from the Siemens to IP phone A this works okay. However when IP phone A is forwarded to IP phone B using CFwdAll the call fails. phone B rings for a fraction of a second(long enough to be heard) and then the call is disconnected.
This fails for calls from Siemens extensions and PSTN.
The interesting thing is that CFwd Busy and CFwd Nio Answer both cause phone B to ring correctly.
CFwd to Voicemail works okay.
Call Pickup functions in the CM work okay.
Under Service Parameters, we are set to use ISO Q.Sig variant, not ECMA.
Calling Search Spaces look okay, and have been verified with the other types of Call Forward.
Any ideas? I'm well stuck!
Try setting the Service Parameter "Disable Alerting Progress Indicator" to True and see if that helps.
Long time back ran into a similar issue with a customer and if I remember right, it was fixed by this Service parameter. The difference was that they were connected to the PSTN via regular PRI.
Thanks for the reply. I have tried changing this, but cannot reset the Call Manager services yet until after hours - it made no difference when I tried it without the service restart though. I'm hoping that restarting CM service will make this take effect...
Will let you know!
I tried the Alerting Indicator change as suggested above and got no difference even after restarting CM services.
As far as CSS and partitions are concerned, these are okay - as stated above, the calls DO get forwarded for Busy and no answer conditions. These were tested using the same CSS / partitions.
Is the PBX set for ISO or ETSI Q.Sig?
I have seen an issue where the Q.Sig message that the call is being forwarded as seen as a re-route request causing the PBX to terminate the call. Changing the Q.Sig type on the PBX solved the problem.
Hi, Thanks for the reply.
The card that they (Siemens) put into the PBX was an ISO Q.Sig card, that much I'm sure of, I saw the order form. But I will ask them to say what the setting is withn the PBX itself. If you're right then I'm going to be a bit annoyed with them, because we clearly instructed them that Call Manager required ISO Q.Sig.
Did you ever manage to figure this problem out? I have the same issue (except with Ericsson MD110 PBX) that I have not been able to figure out how to resolve.
Blimey, I had forgotten all about this post!
The issue was never resolved favourably and we ended up reverting to Q.931 in the end.
I'll try to summarise the reasons below.
We gathered traced from the Router (Cisco) and the Siemens (with the help of a kind and VERY willing engineer within their organisation).
We found that the Cisco was dropping the call after a timeout period caused when the Siemens did not respond to the Cisco indicating the new called number (the number DIVERTED TO).
The Siemens traces showed that Siemens could not understand the information Cisco sent to it indicating the new called party and just sat there. The Cisco then timed out and dropped the call.
The ensueing bun-fight was a real anti-climax though. Although Siemens had told us that their card was ISO-compliant, they were technically correct, because I understand that Q.Sig is an ISO standard in itself. However there are several "sub-profiles" of this standard which include ECMA, ETSI and ISO. The Siemens did not understand the right "sub-profile".
So we were none-the-wiser on this and eventually persuaded the customer to use basic Q.931 as opposed to the alternative, which was to switch the Siemens cards to DPNSS and use a converter such as a Westell IQ2000+ which can present Call Manager with a compatible ISO profile of Q.Sig.
What I understand is that you'll always need such a converter if you're doing Q.Sig from a Realitis / IsDX Siemens to Call Manager. Thesse systems are the old GPT switches that Siemens bought when they acquired GPT. The HiPath 4000 and others in this range are different and I understand that there is the possibility to do direct CM integration with Q.Sig.