Route selection impacts on achieving enhanced IMS QoS
The different planes in the IMS interact via specific reference points to deliver multimedia services to the user. QoS provisioning for IMS communications has been standardized for access networks only, with the assumption of an over provisioned IP core. Effective provisioning of multimedia services requires performance guarantee along the complete path of the sessions. End-to-end QoS in IP networks is affected by the route traversed by the user traffic. Moreover QoS guarantees in one ISP domain are not effective for transit traffic exiting the domain. QoS extensions to exterior gateway routing protocols have been proposed to transfer route QoS information beyond one autonomous system (domain). This paper explores options for mapping inter-domain QoS information learnt on the media plane into control plane session information for IMS QoS control. Through testbed evaluations we show the effect of routing on delays experienced in IMS communications.