This memo describes an application level protocol for the standard communication of e2e QoS compliance information using a protocol based on Hypertext Transfer Protocol (HTTP), which forms the basis for the World Wide Web, and Session Description Protocol (SDP). Quality for Service Protocol (Q4S) provides a mechanism for latency, jitter, bandwidth an packet loss negotiation and monitoring, alerting whenever one of the negotiated conditions is violated. Implementation details on the actions to be triggered upon reception/detection of QoS alerts exchanged by the protocol are out of scope of this draft, it is application dependant (e.g. increase quality, reduce bit-rate) or even network dependant (e.g. change connection's quality profile).