QoS Support for SIP Based Applications in a Diffserv Networks

SIP is currently having a lot of attention as a protocol for session signaling over the Internet. It can cover voice, video and multimedia sessions. Most of these applications are sensitive to the QoS provided by the underlying IP network. Therefore a lot of interest is currently devoted to the interaction of SIP with the QoS mechanism in IP networks. This work will describe an enhancement to SIP protocol for the interworking with a QoS enabled IP network. The proposed mechanism is simple and it fully preserves backward compatibility and interoperability with current SIP applications. Moreover the paper describes the application of this mechanism to a particular QoS enabled IP network, which implements Diffserv as transport mechanisms and COPS for resource admission control. A testbed implementation of the proposed solutions is finally described