andersch.dev

dandersch contact [at} andersch {dot) dev
<2025-03-12 Wed>
[ web ]

SDP (Session Description Protocol)

Session Description Protocol (SDP) is used to describe multimedia sessions. It contains information necessary to set up a media stream between two peers.

It is one of the two key pieces of information (next to ICE candidates) to establish a peer-to-peer media connection using WebRTC.

Offers/Answers

Establishing a media session requires peers determining acceptable parameters. This offer/answer process is defined by RFC 3264.

  • SDP Offer: Details capabilities (supported codecs) and types of media the peer intends to send & receive.
  • SDP Answer: Specifies what peer agrees to, including own capabilities and selected media parameters.