CP-7821 QOS between phones

[pricilla_p]

We have a two story building with 7821's upstairs and downstairs. When calls are made between floors, it sounds like you are talking under water. When calls are made to phones on the same floor the sound is good. Could it be the multicast? No errors or lost packets.

[Jonathan Unger · Accepted solution]

Do you happen to be running the 11.5 version of firmware on the phones, and is the OPUS codec being used for the problem calls?

If so you could be hitting the following bug:

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCvc76073 

We have hit this bug with one of our customers in a similar situation (no network loss or delay and sounding like "underwater" or cut-off audio).

[pricilla_p]

Thank you Jonathan! Phones are running 11.5 and CUCM is 11.0.1.2. Disabled OPUS and sound quality returned to normal.