While Internet is getting richer of multimedia contents, distributed under various formats and with different techniques (pure streaming, downloading, peer to peer), in most cases it is possible to achieve QoS (Quality of Service) only in small domains or with a low number of flows. Many solutions have been proposed in the past, especially in the media downloading field, and new ones are emerging in peer to peer under the form of extended or new signaling schemes.

The standards for the connection establishment have already been defined and implemented, and today they are already used or available to the customers. So, instead of using new type of packets or protocols, our efforts have been spent in adapting the current technologies.

In this paper we focus on pure streaming mechanisms, i.e. a stream of bytes consumed at the arrival to the destination with few or no buffering. Our goal is to show that coupling our active edge routers with a particular type of AF-DiffServ core queue disciplines called GRIP, the RTSP protocol can be easily re-mapped to make it work as an end point signaling protocol.

In fact, our rationale does not rely on changing any field of the RTSP packet but we simply label the packets as probe or feedback via the DSCP, making them become signaling packets able to discover network congestion.