Distributed multimedia applications offer to clients degrees of freedom for selecting Quality of Service (QoS). This paper describes a framework for application level negotiation as a means to regulate client requested QoS under QoS constraints imposed on an application. A QoS architecture is motivated interrelating levels for media specific and transport level QoS handling. The necessity of corresponding protocol levels is explained. The coupling between these levels is demonstrated for a concrete protocol developed for an example application. The embedding of end-to-end delay into the protocol is discussed.