Reviewer: Liang Xia Review result: Ready This document is ready to be published as a Standards Track document. This document provides a general mechanism to use the header extension feature of RTP (the Real-Time Transport Protocol). It provides the option to use a small number of small extensions in each RTP packet, where the universe of possible extensions is large and registration is de-centralized. The actual extensions in use in a session are signaled in the setup information for that session. This document obsoletes RFC5285. This document has addressed all the issues I raised in Secdir review of -09 version, and is a well written now. I don't have any more comments.