Methods and apparatuses provide for listing codecs for offers and for providing an effective listing of codecs for answers. For example, a method relating to offers is provided which includes receiving an incoming offer that lists a plurality of codecs, determining for each of the plurality of codecs whether one or more related codecs are not listed in the incoming offer, generating an outgoing offer that lists the plurality of codecs and the one or more related codecs that were determined not to be listed in the incoming offer, and transmitting the outgoing offer.