2.1 Transport

RTSP requests and responses are sent over either UDP or TCP.<1>

The default port that an RTSP server listens on for incoming requests is port 554, but the use of other port numbers is permitted.

The extensions defined in this specification use the access authentication functionality that was originally defined for HTTP. This is possible because when RTSP requests a response, the syntax of the request is, in many aspects, compatible with HTTP. The specific access authentication schemes supported by any one implementation are implementation-specific.<2>

HTTP access authentication is specified in [RFC2616] section 11.