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New Member

Packet loss

I am trying to eliminate Unity as the source of occasional voice quality issues when calling in to unity. These same issues are experienced on this network when unity is not involved,phone to phone, phone to gateway but.

when capturing traffic coming out of unity, it seems to be pretty consistant

UDP D=30632 S=22928 LEN=180

UDP D=30632 S=22928 LEN=180

UDP D=30632 S=22928 LEN=180

UDP D=30632 S=22928 LEN=21

UDP D=30632 S=22928 LEN=180

the 21 byte is what concerns me . It has been said that this happens at the same time as quality degrades. I do not have access at the moment to capture traffic in another unity environment to compare.

The NIC drivers are new and no errors reported by the NIC at all and I am told by the network managers that there are no issues on the switchport. The server reports no errors and is significantly under utilized. The network devices other than Unity, CCM and the 6500 gateway are another vendors and I am not involved in their configuration.

3 REPLIES
Gold

Re: Packet loss

Check this page:

http://www.cisco.com/warp/public/788/voice-qos/symptoms.html

For samples of some types of voice quality problems. It's common to hear "robotic" or "synthetic" voice quality problems with Unity for whatever reason. Having newer versions of the TSP helps; Unity-CM TSP 7.0(3) fixes bug-id CSCea35850 for example. For external calls, expanding the minimum jitter buffer size can help as well.

New Member

Re: Packet loss

Jason thank you for your reply.

I wonder how they convinced that guy to read back the pink floyd lyrics?

I am at tsp 7.0(3)

The bug referenced is said to apply to outside calls where in this environment inside callers have the same issue. It has not been my experience where robotic or synthetic voice quality has been "common" in other unity environemnts. Not that it doesnt exist but I would say uncommon. Maybe I have just been lucky.

As for the jitter buffer size, that has been addressed but again this is an inside and out experience.

basically if you look at the above capture we see steady 180 and then when quality decreases (garbled)we see the 21 and then a pause in transmission, and then 180 again for some time. keep in mind that this same voice quality issue is experienced, phone to unity, phone to phone and phone to gateway.

I am reasonably confident based on my experiences that unity is not the culprit here It's just that the 21 and the the pause in transmission is a little suspect and although I can access other unity environments right now i cannot capture from my current location. So i was hoping for a maybe a comparison of someones capture or another opinion on the 21 and then the pause.

New Member

Re: Packet loss

Were you able to find resolution to this issue? I am experiencing similar issues when using G729.

Thank you,

Jamie

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