5. SDP Signaling

This section defines a new SDP [4] attribute, "rtcp-xr". Applications employing SDP can use this attribute to express an intent to use RTCP XR packets and to specify which XR block types will be used. This section describes the use of the "rtcp-xr" attribute within and outside of the SDP Offer/Answer model [8], which governs parameter negotiation in protocols that employ SDP such as SIP [12].