Hi Support Community
Call Flows
- SIP ISP > CUBE > CUCM 8.6 > Cisco 7841 IP Phone
- SIP ISP > CUBE > CUCM 8.6 > Cisco Meeting Place 8.5.4 ( located across the WAN )
- SIP ISP > CUBE > CUCM 8.6 > Cisco Unity Connection 8.6 ( located across the WAN )
Issue
Call Flow 1 never has an issue.
Call flow 2 has an issue with approx. 1 in 50 conferences with a machine gun type noise heard on the conference
Call flow 3 has an issue with approx. 1 in 100 Voicemails with a machine gun type noise heard on the voicemail
We have this issue for quite some time but it only crops up intermittently so its very difficult to gather traces. We finally managed to gather enough information to narrow down the source of the issue. It seems the SIP provider for the issue calls are passing us in the SDP "Media Attribute (a): ptime 60". It also seems to be the same clients who have the issue so I suspect their Telco is creating the 60ms ptime.
We have logged this in the provider and they tell us that they just pass what they receive and they don't have any transcoding available in this region to do anything with the call.
I have a few queries regarding this :
- Why do the IP phones receiving a direct call never have an issue
- What would we need to do to fix this issue for these certain calls without sending all calls to an MTP
Thanks, Carl Ractliffe
Preston Lancashire England
