Media and Codecs
Although SIP meets the needs for signaling information in calls, VoIP PBXs still require a method to transmit the actual media stream, whether it is audio or video. The Real-Time Transport Protocol (RTP) is used in almost every VoIP implementation and was developed specifically for transmitting audio and video traffic across networks. Encryption of the media traffic was later added in the form of Secure Real-Time Transport Protocol (SRTP), which is what Lync Server 2013 uses by default to ensure that the media cannot be intercepted and played back.
It’s important to note that RTP and SRTP only provide a standard for carrying the media traffic which can be composed of various media codecs. Think of the RTP stream as a wrapper ...
Get Microsoft® Lync® Server 2013 Unleashed Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
