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Call Manager - Fax, Call Quality and Registration Issues


Newbie here, so I apologize in advanced for asking a redundant question or leaving out information in this post... I'm also in slightly unfamiliar territory with VoIP.

I am experiencing some issues with our voice network. The issue is ever since we upgraded to a 2821 and CCM to 4.1(3)sr4b we slowly loose our fax lines, then our 7912's have problems with voice quality and registering, then we start having issues with our 7960's which slowly increases to not being able to call in from the outside to these phones.

At first we thought it was a QoS problem but to the best of my knowledge AutoQoS is configured correctly. To clear this issue up having limited knowledge of CCM/VoIP, we thought a reboot of our switches and VGW router would clear up this issue, but it did not. We then rebooted our CCM's which then fixed our issue for about 2-3 days. After this amount of time, the issues slowly creep back up to the point at which we have to reboot out CCM's again.

I'm going to open a TAC when this issue creeps back up again but in the mean time I figured I'd post in hopes of finding a solution, quicker.

Thanks for taking time to read this and please reply if more information is needed.



Community Member

Re: Call Manager - Fax, Call Quality and Registration Issues

Starting at a simple level, make sure that your server processor and memory utilization are not going up dramatically, leading to these issues, then a reboot fixes it.

The other thing to check is make sure that you not only have Autoqos turned on the phone ports, but on the ports that the actual CCM servers plug into as well.

So on a server port you should have "autoqos voip trust", as well as "mls qos trust dscp", or a similar command depending on IOS version.

Community Member

Re: Call Manager - Fax, Call Quality and Registration Issues

Thanks for this. Verified that autoqos is enabled on the switchports... I will have to wait to see what the processor and memory are doing when the problem occurs next. I was told by TAC that I should upgrade to a different patch on our CCM. I will also be modifying QoS for best practices on the switches. Any other ideas are more than welcome. Thanks again for taking the time to reply.

Community Member

Re: Call Manager - Fax, Call Quality and Registration Issues


We just upgraded a 4.02a system that had been stable for over 2.5 years to 4.1(3)sr4d and are having the same issues with faxes. We are not seeing the issue with voice QoS you mentioned but defintly are seeing issues with faxes.

We do notice however that the subscriber does have some issue with CPU after the upgrade which seems to be related to Explorer. System is a MCS7845 equivilent HP DL380 dual 3.6mhz Xeon system with 4Gb memory so proc peaks are in the 50% and meory is low.

Did you ever get a TAC resolution to this isse?

Community Member

Re: Call Manager - Fax, Call Quality and Registration Issues

Sorry for the late reply... TAC still has not resolved this and our case is still open. However, I may have narrowed down the cause of this. We are a software development company and our developers are working on some technology that uses multicast heavily. I disconnected one of the developers out of curiosity one day and that seemed to reslove our issues. However, we were running very stable before the upgrade, like you were. We are waiting to hear back from a QoS tech to see if we need to be filtering additional multicasting traffic. I will try to keep you posted on what we find out.

Maybe you are running into the same thing? We have got a Cisco best practice QoS templet in place instead of AutoQoS and VLANs for Data and Voice and this is still happening. Keep me in the loop if you have found a resolution.



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