Aziz Mohammed

DiffServ experiments: analysis of the premium service over the Alcatel-NCSU Internet2 testbed

In the Internet2 community, there is a heightened level of activity both in the development of advanced applications that require quality of service (QoS) for operating effectively and the enabling network infrastructure over long distances. As members of this community and leading technologists in Internet, Alcatel and North Carolina State University (NCSU) have jointly launched a fully operational virtual Lab between Alcatels Research & Innovation Center in Richardson, TX and NCSU campus at Raleigh, NC across the Internet2 national backbone network. We report the first set of results from a Differentiated services (DiffServ) field trial over this large-scale testbed involving network equipment from Alcatel and other third party vendors. Results of the experiment show that DiffServ is capable of delivering the premium service using its expedited forwarding per hop behaviour (EF PHB) for a large class of bandwidth starving applications. However, it is found that DiffServ needs some additional mechanisms to efficiently deliver similar services for jitter and delay sensitive applications, especially in a severely congested network.

A traffic congestion detection mechanism for QoS using RTFM architecture and IDC

Congestion detection and control mechanism is an integrated function of any quality of service scheme to provide differentiated services during network congestion. This paper presents a new approach to congestion detection and avoidance based on real-time traffic flow measurement and the statistics of index of dispersion for counts. This approach passively monitors the underlying network traffic flow, and detects or predicts the network congestion without relying on transport-layer protocols or feedback signaling. An experimentation of applying this scheme in a validation testbed is presented with results illustrating the effectiveness of the approach in practical scenarios.

DiffServ experiments: evaluation of some approaches to quality of service control over the Alcatel-NCSU Internet2 testbed

Technological communities that are formed on the basis university, industry and government partnerships are developing and deploying advanced network applications and technologies, accelerating the creation of tomorrows Internet. Alcatel and North Carolina State University (NCSU) have jointly launched a virtual Lab between Alcatels Research & Innovation Center in Plano, TX and NCSU campus at Raleigh, NC across the Internet2 national backbone network. The objective of this co-operative work is to conduct a large-scale field trial in the currently deployed state of the art QoS technologies and investigate areas of improvement. Results from phase one of our work in a Differentiated services (DiffServ) experiments over this testbed involving network equipment from Alcatel and other third party vendors show that DiffServ is capable of delivering the premium service using its expedited forwarding (EF) per-hop behaviour (PHB) for a large class of bandwidth starving applications. However, it is found that DiffServ needs some additional mechanisms to efficiently deliver similar services for jitters and delay sensitive applications, especially in a condition of severely congested network. The situation is even more complicated when one considers resource-sharing environments beyond the extreme cases of EF and best effort (BE) only. The second phase of our work involves investigating empirically and through simulation, a fine-grained new integrated scheduling scheme to extend the DiffServ with a variety of adaptive queue management (AQM) solutions and study their effect on end-to-end (e2e) DiffServ experiments involving not only EF/BE but also assured forwarding (AF) traffic.