[cisco-voip] 6608 XCODER vs 3945 XCODER and SIP calls (Nuance Speech Attendant)

[Lelio Fulgenzi]

We had a very interesting problem after I migrated from 6608 resources to 3945s. In particular, we have a Nuance Speech Attendant system integrated using third party advanced SIP phones (one for each server). Each SIP phone can handle 8 calls. The SIP phones have MTP required checked. 

Here's what happens: 

Problem: Callers reported hearing dead air when calling the speech attendant. Further research showed that the problem occurred on the third and subsequent calls, regardless of which server the call was on, so in effect, we could only process two calls at a time. 

After some troubleshooting and researching, we found that it was not the removal of any OLD (transcoding) resources but the addition of NEW (transcoding) resources that caused the problem. This was difficult to catch because not only did Nuance NOT use the old transcoding resources, but only used the NEW transcoding resources on the third and subsequent calls. This is very odd to say the least. In the old MRGL, we had two software MTP resources (two subscribers), in the new MRGL we had these two MTP resources, plus the new XCODERs on the 3945s. Part of the troubleshooting also included specifically assigning the old XCODER into the MRGL. 

The solution was to create new media resource groups (and lists) so that the new transcoding resources were not accessible by the Nuance system. 

I suspect, that the new XCODERs on the 3945s are advertising/negotiating MTP abilities when they really aren't. 

Can anyone help me understand what just happened? 


--- 
Lelio Fulgenzi, B.A. 
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1 
(519) 824-4120 x56354 (519) 767-1060 FAX (ANNU) 
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Cooking with unix is easy. You just sed it and forget it. 
- LFJ (with apologies to Mr. Popeil) 


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