[cisco-voip] Delay in audio between IP phones on same switch

[Rhodium]

Hi all,

I have this issue where 2 IP phones sitting on the same switch have audio delay in the beginning of the call occasionally.

I ran a sniffer trace and collected the CUCM SDI traces and there is no delay at all with the SCCP messages or the establishment of the RTP stream.

- codecs negotiated correctly with no change over mid stream
- right ports referenced in open channel sccp messages
- ARP request is made by both IP phones looking for each other's mac and that is responded to by the target IP phone
- RTP stream is started immediately after ARP request and can be seen in the sniffer trace but no audio is heard by the respective IP phones until a few seconds later.
- Silence suppression is disabled on CUCM (v4.1)

Any subsequent calls after this initial problem function normally with no delay in audio.


Any pointers would be helpful.

Regards,

J