Developing quality of service management architecture for delivering multicast applications
Multicast applications have been a topic of intense research and development efforts over the past couple of years. Both the Internet Engineering (IETF) and International Telecommunication Union (ITU) have been heavily involved in providing quality of service to support multicast application requirements. Multicast applications have varying performance requirements; therefore it is necessary to design a framework that serves to guarantee quality of services. However the existing best effort services cannot provide the guaranteed service level required by multicast applications. Two solutions have already been proposed to overcome this problem. The first solution proposed the tree-based functionality approach in the multicast transport protocol providing reliability and scalability between a sender and a group of receivers. The other solution has proposed end-to-end quality of service (QoS) over the network environment using interoperation of Integrated services (IntServ) and Differentiated services (DiffServ) principles. Both QoS architectures, Integrated and Differentiated services, have their own advantages and disadvantages. With the interoperation of both architectures, it might be possible to build a scalable system, which would provide predictable services. This framework has to be supported by a multicast transport protocol to provide reliability and scalability over the nodes. The aim of this research is to develop a framework to provide reliably and scalability on nodes (tree-functionality) along with the end-to-end resources, dynamic admission control and scalability over the network (interoperation of IntServ and DiffServ) for multicast applications. The "Enhanced Communication Transport Protocol" (ECTP) transport protocol was chosen for this research. ECTP transport protocol is a multicast transport protocol with tree-based functionality to support multicast applications. ECTP transport protocol is also able to provide QoS management functionality established by Integrated or/and Differentiated services to support multicast application. With the QoS management functionality, ECTP transport protocol could provide reliability and scalability (over nodes) along with end-to-end resource, dynamic admission control and scalability over the network for multicast applications. This research is focused on the further enhancement and implementation of an ECTP transport protocol, QoS management specification. Two models have been proposed to enable ECTP transport protocol with QoS management functionality established by the IntServ or/and DiffServ principles. Model (I) enables ECTP transport protocol to negotiate end-to-end resource reservation using the standard RSVP (IntServ) signalling protocol. Model (II) enables the ECTP transport protocol to negotiate end-to-end resource reservation using the standard and aggregated RSVP (IntServ and DiffServ) signalling protocol. The "Optimized Network Engineering Tool 8.1" (OPNET) has been used in this research to implement and investigate the ECTP specifications. OPNET simulator provides a comprehensive development environment for modelling and performance of communications networks. The investigation consists of three case studies. The simulation results have proved that ECTP transport protocol with the tree-based functionality and the QoS management provided by IntServ and DiffServ interoperation produces the best performance for the traffic delay parameter over voice applications.