A method to efficiently integrate Internet Telephony call signaling with dynamic resource negotiation

摘要

Internet Telephony imposes Quality of Service (QoS) requirements in terms of delay, jitter and loss ratio to provide reliable, high-quality multimedia services. While the Internet has historically offered a best effort service, it is hard to satisfy the required QoS of multimedia applications. In order to provide a tight QoS guarantee to telephony services, priority must be offered to real-time flows. Dynamic resource negotiations are required at the beginning of sessions besides long term service contracts. Most of the researchers propose to integrate call signaling with resource negotiation in a sequential manner [G. Camarillo, W. Marshall, J. Rosenberg, Integration of Resource Management and SIP, IETF RFC 3312, October 2002; P. Goyal et al., Integration of call signaling and resource management for IP telephony. IEEE Network, 13(3) (1999) 24-32; H. Schulzrinne, J. Rosenberg, J. Lennox, Interaction of call setup and resource reservation protocols in Internet Telephony. Technical Report, Columbia University and Bell Laboratories, June, 1999. Available from: http:// www.cs.columbia.edu/~hgs/sip/drafts/resource.pdf]. This method can provide QoS at the highest level, but it results in high call setup delay and high probability of connection failure. Parallel integration is an alternative method that can mitigate these drawbacks. In this paper, we proposed a detail solution based on the parallel approach to establish resource negotiation simultaneously with call signaling. This approach can apply to different QoS models and mechanisms such as Integrated Services (IntServ), Differentiated Services (DiffServ) and Multi-Protocol Label Switching (MPLS). This paper presents the architecture and system design of the parallel signaling approach. Threshold quality control scheme is applied to guarantee that the service is above the acceptable level before a telephone session begins.