[cisco-voip] Preffered codec for Call Manager SIP Trunk to ITSP

[Mark]

So, when UCM7 sends a SIP Invite out a SIP Trunk it only includes one codec in the SDP? This seems odd to me, because most IP PBX's will support a preferred codec list.  When trunking to an ITSP this makes it difficult to have a simple approach to support multiple codecs on the Trunk.  Many ITSP's will REINVITE to G.711 when there is fax-modem detection.  Also, if the ITSP is a well-known SIP Trunking ITSP and has multiple UCM customers, and one location is setup for G.729 and the other is G.711, the call will fail when the called party picks up since there is no common codec for media negotiation.  The only solution I see to this is transcoding on the customer router, but it's not realistic for the ITSP to force this upon the customer.