An efficient bandwidth management scheme for real-time Internet applications

Differentiated services (DiffServ) was recently proposed by the IETF as a scalable solution for the Internet QoS. Within the DiffServ architecture, premium services is a service class which is proposed for interactive real-time applications like Internet telephony or video conference. In order to ensure the service quality of premium services, each DiffServ domain needs to appropriately negotiate a service level agreement (SLA) with its customers and neighboring domains. Because the resources for premium service is usually a small part of the total network band-width, dynamic SLA negotiation is preferred to maximize the resource utilization. However, a completely dynamic SLA negotiation scheme introduces scalability problem for the bandwidth broker (BB). In this paper, we introduce the concept of 'pipe' as a viable solution for this scalability problem. We propose a simple threshold-based updating scheme for the pipe which incurs an acceptable updating overhead for the BB while maintaining a high utilization of the pipe. We study the performance of the threshold-based updating scheme and compare it with an ideal updating scheme. The ideal scheme is theoretically optimal as it uses future knowledge for periodically updating the pipe capacity. The performance of the threshold-based updating scheme is very close to the ideal updating scheme.