Cisco Cisco The Real-Time Communications in WEB-browsers (Rtcweb) working group is charged to provide protocol support for direct interactive rich communication using audio, video and data between two peers' web browsers. With in the Rtcweb framework, Session Description protocol (SDP) is used for negotiating session capabilities between the peers. Such a negotiation happens based on the SDP Offer/Answer exchange mechanism. This document provides an informational reference in describing the role of SDP and the Offer/Answer exchange mechanism for the most common Rtcweb use-cases.