[cisco-voip] Echo on international calls

[polo person]

Hi,

I've not done any testing regards this problem yet (you'll see why in a minute), but I thought I'd share the symptoms first in case anyone has experienced it before and can give some suggestions as to where to look first.

We have a big call manager system with 1 pub, 1 tftp and 6 subs (arranged as 3 live, and 3 failover), with around 5,000 extns registered on each sub. We also have 2 x 3845 Gateways each with 3 NTL ISDN30's (for out bound calls) and 3 BT ISDN30's (for inbound calls)

We upgraded our Call Manager from v7 to V8.0.2.41900-3  over the Christmas period.  Before xmas all seemed ok, but just after xmas, one of our sites (whose extensions will probably all be registered with one sub) reported that they were hearing a bad echo on inbound international calls after 2 to 3 seconds after call set up.  They don't make many (if any) outbound international calls, and the inbound calls only happen for the first couple of weeks after xmas and have now died down. (Yeah.... really helpful!)

They also don't know if the echo was only at their end, or at the far end as well.

So, plenty of blanks to fill yet, but few opportunities for testing and debugging unfortunately. I really do get all the good jobs!

Where would you clever folks start to look on this one?

Cheers

Simon



 

 		 	   		  
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