• Both intend to support the creation of media sessions between two IP connected endpoints and both use SDP
  • SIP strength is in connecting to the telecom world, WebRTC strength is in the internet world
  • SIP is a signaling protocol. WebRTC needs one but doesn’t have one defined . It can use SIP or other signaling protocols
  • WebRTC mandates the used of some SIP optional features: SRTP, DTLS, specific codecs, etc.

Interoperability differences between SIP and WebRTC

Media transportRTP, SRTP (opt)SRTP, new RTP Profiles
Session NegotiationSDP, offer/answerSDP trickle
NAT traversal STUN TURN ICE ICE (include STUN/TURN)
Media transport Separate : audio/video, RTP vs RTCPSame path with all media and control
Security Model User trusts device & service providerUser trusts browser but not website
Audio CodecsTypically G.711. G.729 G.722 SpeexMandatory Opus & G.711, optionally others
Video CodecsTypically H261 H263 H264Undefined yet but likely VP8 and or H264