RTP has important properties of a transport protocol:

it runs on end systems, it provides demultiplexing. It differs from transport PROTOCOLS like TCP in that it (CURRENTLY) does not offer any form of reliability or a protocol-defined flow/congestion CONTROL. However, it provides the necessary hooks for adding reliability, where appropriate, and flow/congestion control. Some like to refer to this property as application-level framing (see D. Clark and D. Tennenhouse, "Architectural CONSIDERATIONS for a new generation of protocols", SIGCOMM'90, Philadelphia). RTP so far has been mostly implemented within applications, but that has no bearing on its ROLE. TCP is still a transport protocol even if it is implemented as part of an application rather than the operating system kernel.

RTP has important properties of a transport protocol:

it runs on end systems, it provides demultiplexing. It differs from transport protocols like TCP in that it (currently) does not offer any form of reliability or a protocol-defined flow/congestion control. However, it provides the necessary hooks for adding reliability, where appropriate, and flow/congestion control. Some like to refer to this property as application-level framing (see D. Clark and D. Tennenhouse, "Architectural considerations for a new generation of protocols", SIGCOMM'90, Philadelphia). RTP so far has been mostly implemented within applications, but that has no bearing on its role. TCP is still a transport protocol even if it is implemented as part of an application rather than the operating system kernel.