[cisco-voip] Cisco g729 codec issue with SIP endpoint non RFC3555 compliant

[tele]

Hi,

Related to this annoying issue, i've found this thread on Netpro:

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=Unified
%20Communications%20and%20Video&topic=Video%20over%20IP&CommCmd=MB%3Fcmd
%3Dpass_through%26location%3Doutline%40%5E1%40%
40.1dde3e51/1#selected_message

Cisco in another document says:

http://www.cisco.com/en/US/products/hw/routers/ps259/products_tech_note09186a00800a74d7.shtml#sip

In IOS SIP gateways complaint to RFC 3555, you need to specify the exact
G.729 type of codec in the configuration. Another solution is to
downgrade the IOS to a version which is not RFC 3555 complaint. Refer to
Enhanced Codec Support for SIP Using Dynamic Payloads for more
information on G.729 codecs on SIP gateways.

How can i specify the exact codec type? like the netpro guy if i specify
only g729r8 and i receive from the SIP endpoint in the SDP no annexb=no
line, for cisco (rfc3555 compliant) the codec is g729br8!
If i specify two codec g729br8 and g729r8 in a voice class the sip
endpoint don't work.

look the table:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00800b5d75.html#29898

Is there a solution to this issue? I cannot downgrade my IOS.
This cause interoperability problem between switch, and i'm using it in
a IP-to-IP GW.

any ideas?

thanks

:tele