So I've been through with wringer with WebEx support on this and am drawing a blank... We recently (After getting hit with large overage charges on our toll-free usage) began asking all users to switch to calling into the WebEx meetings using the toll number provided by WebEx. About a week after doing this, 4 or 5 users have come mentioning issues where their digits entered for the meeting ID are read back incorrectly by WebEx which leads them to being kicked off the call and unable to join their meeting. This ONLY happens if they call using the toll number - call in using the toll-free and everything is perfectly fine. It also appears this MAY be tied to only one meeting, but I haven't confirmed that quite yet for sure.
This sounds like a DTMF signaling issue, because random digits in their string will be duplicated, similar to an old bug I read about, but we're on IOS 15.04 on our 2911 GW which is well past when that bug had been fixed.
I submitted a support ticket to WebEx and they can't reproduce the problem, but it seems to be popping up pretty frequently for at least all users getting into this one specific meeting whether calling from a desk phone (7941/8945 SCCP or Jabber Windows client). All calls exit the same SIP GW from our datacenter, but the fact this can ONLY be reproduced when calling WebEx's toll-free number tells me it may be something on their end.
The only dtmf related config on our GW at the moment is dtmf-relay rtp-nte on all of our dial peers. I was tempted to play with some of these settings, but seeing as this has never been an issue in the 18 months+ since implementing our CUCM it seems strange to believe it could be something on our end. Only way to know for sure seems like it would have to be a packet capture and debug on GW at the time of joining the meeting to see what's really being sent?
Thoughts?
