A concept of Session Description Protocol (SDP) templates and a concept of template modifiers for precise control of media types, codecs and attributes offered by a media server are described along with various methods and mechanisms for administering the same. Applications can solicit offers from media servers that precisely meet the requirements of each session, using one or more media control protocols. The media control protocols may enable applications to reserve media resources, invoke specific functions, respond to events during session initiation, and provide session modification.