Technology and Support Collaboration, Voice and Video IP Telephony and Phones

[mugof]

I have a problem on CUCM 11.5, some 7945s have no audio when connected to some cisco phones on the same LAN. The call rings and gets connected but no audio. This problem started after replacing network switches with WS-C3650-48PQ. 

How to solve this please.

[Jaime Valencia]

One way audio or no audio are most usually routing issues, make sure the two endpoints are able to send/receive RTP in your network.

[mugof]

Only specific endpoints behave like this randomly even after working fine previously. There is no change in configuration. All other endpoints work fine. Since it's within the LAN, no firewall is involved. The same endpoints that are affected in this way can call other endpoints at the same time within  the same LAN just fine. But not others. Same switch port configurations. So the RTP connection is formed for some and not other call connection. 

Confusing.

[Jaime Valencia]

Look at the call stats, do you actually see packets arriving to the phone?

[mugof]

Please see the stats attached. Both phones appear to be sending and receiving pkts which keep increasing