Load Balancing in Hop - by - Hop Routing with and without Traffic Splitting

This dissertation presents an exploration on solving traffic load balancing problems concentrating on the IP layer in hop-by-hop networks. The first part of the traffic load balancing research is focused on bandwidth-sensitive routing for premium class traffic in Differentiated Service (DiffServ) networks, where bandwidth usage of the premium class traffic is critical not only for the traffic itself, but also for other classes of traffic with lower priorities in the same network, such as the assured or best effort traffic. If the traffic in a network is splittable, then the second part of the load balancing research is intra-domain traffic engineering in the network, where the bandwidthsensitive routing solutions in the first part can be used to achieve better traffic load balancing results in this part. Hop-by-hop routing is the base routing paradigm in today’s Internet. It is routing-table-driven and destination-address-based. This means, firstly, each node (router) in such a network constructs its routing table independently using its own topology information about the entire network; secondly, each node looks up the next hops in its routing table for incoming packets based on their destination addresses. No flow information or source address information is used while forwarding. Therefore, an important issue in a hop-by-hop network is the avoidance of forwarding loops. Since each node makes routing decisions independently, the used routing algorithm should be consistent so that the forwarding loop-freedom is ensured. Most of existing routing schemes are based on the Dijkstra’s algorithm, by applying different weight functions. In the first part of this dissertation, a fundamental relation between weight functions and the routing consistency of Dijkstra-based algorithms is explored theoretically, and this forms the basis for the rest of this dissertation. Quality of Service (QoS) provision is one of the key issues for today’s Internet Service Providers