CODEC Filtering
SIP as such supports wide variety of CODEC - pcmu,pcma,g711,g726,g729,g722,gsm,amr amp-wb h263...
while you may have your own codec preference which you would want to enforce -
Also you may want prioritize your response over a local preference than a remote preference -(local preference means option configure in Genesys would take preference while Remote means SM or the preference from the gateway will be used.
if you would want to set a preference over pcmu over puma and in a INVITE which contain both PCMU 0 and PCMA 18 in it, if you want to communicate over just PCMU 0 , the you could set your config as follows :
In SIP Server - set the audio-codecs- telephone-event, PCMU,PCMA,G711,G729.G722....(list of supported protocols) and set sip-enable-sdp-codec-filter to be true.
following this in MPC -
set codecpref to be local and codec option - pcmu,pcma,g711,g726,g729,g722
and also set answerwithonecodec to be 1 -
by this way you could get the response with single codec, set the preference to be local preference and also limit the distribution of rftpmap message that is sent on the re-invite message to gateway back.
so this would be like,
if the invite comes with PCMU and PCMA - (per the above preference and config set) we would respond back with PCMU.(PCMU will be negotiated)
if invite comes with PCMU only then PCMU only will be negotiated.