This specification defines a new SDP Grouping Framework extension, "BUNDLE", that can be used with the Session Description Protocol (SDP) Offer/Answer mechanism to negotiate the usage of bundled media, which refers to the usage of a single 5-tuple for sending and receiving media associated with multiple SDP media descriptions ("m=" lines). This specification also updates sections 5.1, 8.1 and 8.2 of RFC 3264, in order to allow an answerer to in an SDP answer assign a non- zero port value to an "m=" line, even if the offerer in the associated SDP offer had assigned a zero port value to the "m=" line.