Research On Scalable Multicast Admission Control

Multimedia services are more and more popular in Internet with the widely use of broadband network. It is widely accepted that multimedia services will consume most of the link bandwidth in the next generation Internet. Among multimedia applications, a large number of them are based on point to multipoint transmission. Multicast is an efficient approach to saving bandwidth for this category of application. To guarantee the quality of service for multimedia communication, admission control is required to control the online session number, so that the QoS of the admitted sessions will not be violated. For this sake, admission control has been a hotspot for years. In recent years, scalability of admission control is widely concerned, and various scalable admission control schemes are proposed. However, these schemes only consider unicast case. Admission control for multicast has become a potential bottleneck for the future vast multimedia applications. Admission control could be classified into three categories: probe-based, model-based and measurement-based admission control. Focused on scalable multicast admission control, all the three categories of admission control are studied. The work is introduced in the dissertation. The dissertation contributes in following aspects. (1) In probe-based admission control area, the dissertation finds and enhances the subsequent request problem. Probe schemes in probe-based admission control are also summarized and compared. Subsequent request problem prevents the multicast group from admitting subsequent requests in heavy loaded scenario, which do not consume any more resource of bottleneck link. This seriously influences the scalability of probe-based admission control for multicast. This problem is first found, modeled and analyzed the dissertation. An enhanced scheme using complementary probing is proposed, and validated with analytical models and simulation results. The implementation of the enhanced scheme in DiffServ network, as well as the incriminatory deployment, is also discussed. Probing scheme, which is the soul of probe-based admission control, is also summarized, and compared via analytical model and simulation results from admission correctness and dynamic group scalability. (2) In probe-based admission control area, the dissertation proposed VloQ, a virtual-topology-based network resource management mechanism, and an edge reservation-based admission control scheme for multicast. The concept of multicast virtual link is proposed in the dissertation. Using the concept, a resource management mechanism –VloQ is introduced, which could efficiently reduce the QoS states to maintain. A scalable reservation-based edge admission control scheme is proposed, which employs VloQ and a two layered distributed bandwidth broker architecture. We develop a simulation platform based on discrete control event. Using this platform, Quota management issue is investigated. (3) In measurement-based admission control area, a practical effective bandwidth algorithm is deduced for generalized homogeneous traffic, and a measurement based edge admission control scheme is proposed. Generalized homogeneous traffic, which is extended from homogeneous traffic, is more practical than homogeneous traffic. Using statistical network calculus, a practical effective bandwidth algorithm is deduced for generalized homogeneous aggregation traffic. This algorithm only requires shaper type on edge nodes, whereas the conventional effective bandwidth theory needs the knowledge of source model. A measurement-based multicast admission control scheme is proposed, which utilizes effective bandwidth algorithm and edge multicast admission control framework. A packet-based simulation platform for multicast admission control is developed. The dissertation introduced the design and development of the platform. Using the platform, simulations are designed to evaluate the proposed measurement-based admission control scheme.