Unified Plan is an IETF draft proposal for signaling multiple media sources in SDP.

Signaling multiple media sources is needed to be able to send a video along with screen sharing, multiple camera sources or routing multiple streams from an SFU to the users.

In Unified Plan, there is an m= line per each media source.

The mechanism chosen for the official WebRTC specification is Unified Plan. The competing approach is known as Plan B.

Today, all browsers support Unified Plan by default.