Providing quality of service to internet applications using multiprotocol label switching

The growth of the Internet and the range of applications it now supports has created a need for improved traffic engineering techniques. One protocol which shows promise in this regard is Multiprotocol Label Switching (MPLS). MPLS inherits a mix of attributes from earlier protocols such as IP and ATM, and potentially combines the simplicity of IP and the Quality of Service (QoS) capabilities of ATM. MPLS is now a mature standard widely deployed in the Internet. This thesis concerns the development of new mechanisms that can further extend the MPLS capabilities for traffic engineering. Web service remains a key application in today's Internet. The traffic demands at popular Web-sites and the requirements of redundancy and reliability can only be met by using multiple Web servers. A new solution to Web server load balancing based on MPLS is presented in this thesis. This solution features a novel Web switching architecture featuring switching at layer two. An extended solution for providing differentiated Web services is also proposed . It has been implemented in a soft MPLS router using the Linux operating system. The performance of soft routers is significantly affected by the packet processing time. An MPLS-based framework to increase the average packet size and consequently reduce the traffic frame-rate is described in the thesis. This has been implemented in a Linux-based soft router and its performance evaluated experimentally. As transmission rates continue to rise, such aggregation techniques will be needed if packet processing time is not to become a bottleneck. The switching technology at the core of tomorrow's Internet, featuring GMPLS and optical switching using , perhaps, optical burst switching technology, will not work efficiently with short packets. A new class of scheduling algorithms is also described, intended for deployment in MPLS networks. Their operation is based on an analogy with the workings of the human heart. This class of algorithms achieves the optimal fairness for packet based schedulers and has low hardware complexity. It can be combined with the packet aggregation mechanism above to provide an effective interface between the edges of tomorrow's Internet and its high-speed core

Scalable QoS routing in MPLS networks using mobile code

In a continually evolving Internet, tools such as Q u a lity o f Service ro u tin g must be used in order to accommodate user demands. However, deploying and developing QoS routing in the legacy Internet is difficult. Multiprotocol Label Switching (MPLS) facilitates the deployment of QoS routing, due to its separation of functions between the control and forwarding plane. Developing QoS routing raises scalability issues within very large networks. I propose overcoming these issues by using topology aggregation and distributed routing based on modem techniques such as active networks and mobile agents. However, topology aggregation introduces inaccuracy, which has a negative impact on QoS routing performance. To avoid such problems I propose a hierarchical routing protocol, called Macro-routing, which by using distributed route computation is able to process more detailed information and thus to use the most accurate aggregation technique, i.e. Full-Mesh. Therefore, the protocol is more likely to find the best path between source and destination, and can also find more than one available path. QoS routing, which is used for finding feasible paths that simultaneously satisfy multiple constraints, is also called multiple-constrained routing and is an NP-complete problem. The difficulty of solving such problems increases in a hierarchical context, where aggregation techniques influence the path computation process. I propose a new aggregation technique which allows the selection of multiple paths that satisfy multiple QoS constraints. This reduces the probability of a false negative, i.e., of the routing algorithm incorrectly reporting that no path satisfying the constraints exists. This aggregation technique is called extended full-mesh (EFM) and is intended for use with the Macro-routing protocol. Deploying these protocols in the Internet will allow multi-constrained routing to be practically implemented on large networks