Integration of call signaling and resource management for IP telephony

IP telephony presents a tremendous opportunity to service providers to offe r both traditional services as well as a range of creative new services. Ho wever, there are substantial challenges to be faced in supporting a resourc e management framework that is adequate For telephony, and in providing a s ignaling architecture that enables these services while preserving user pri vacy and preventing theft of service. This article describes the Distribute d Open Signaling Architecture, a framework for call signaling and resource management that meets these needs. A kev contribution of our work is a reco gnition of the need for coordination between call signaling, which controls access to telephony-specific services, and resource management, which cont rols access to network-layer resources. We evaluate one approach to resourc e management in the backbone, consistent with our architecture, using signa ling for aggregates of flows. Using traces from calls on the AT&T long dist ance network, we show that the multiplexing gains achieved by such aggregat ion can achieve most of the benefits of per-flow signaling, while avoiding its overheads. We also evaluate scheduling algorithms in order to understan d their effect on the end-to-end delay experienced by voice packets.