On overlapping resource management and call setup signaling: a new signaling approach for internet multimedia applications

Abstract

Interactive multimedia applications combine requirements of traditional telephony services and Internet applications. This requires call setup, call signaling, negotiation, routing, and network resources. However, in dynamic network environments resources are not protected unless the applications reserve them for the multimedia session. To provide quality of service (QoS) control, the subject of the interaction of call signaling and resource management have addressed resource reservation during the call setup phase. Usually, the rule is to use the traditional telephony-style call setup model (i.e. users are only alerted after all resources have been successfully reserved for the call). In the Internet, however, this may incur in long call setup delays and a high call blocking rate (‘no QoS/no call’). In order to provide users with a practical and fast way to reserve resources during session setup, we investigate a different call setup model than that of traditional telephony. Our model allows users to be alerted while the resource reservation takes place, thus, taking advantage of parallel user answering delays and reservation delays. For this to occur efficiently, we use existing elements of the Session Initiation Protocol (SIP) to provide means for independent call setup and resource management transactions and flow negotiation. Based on experimental comparisons obtained in a multimedia call, we demonstrate that the proposed approach reduces the impact of the reservation delays, with maximum call setup delay improvements when we have approximate values of reservation and answering delays.