AuthorsA. F. Hansen
TitleFast Reroute in IP Networks
Publication TypePhD Thesis
Year of Publication2007
Date PublishedSeptember
PublisherUniversity of Oslo
Thesis Typephd
ISBN NumberISSN 1501-7710

More and more applications with stringent requirements to delivery are being offered through the Internet. Typical examples are real time applications like voice over IP, IP TV, and business critical applications. If a component in the network fails, it is important to be able to route the traffic on other resources very rapidly. For IP networks, this is currently not the standard. The IP re-convergence process that is specified in the most common link state routing protocols does not operate in a time-scale that is compliant with the new type of applications. The IP protocols are continuously being deployed in different kinds of networks. Wireless networks and special purpose networks like sensor networks serve as present examples. These networks may require even stronger requirements to resilient routing due to higher frequency of failures than what has been common in traditional IP networks. The main theme for this thesis has been to develop and evaluate schemes that offer fast reroute around failed components in packet networks. First, we propose and evaluate a scheme named Resilient Routing Layer (RRL). RRL builds backup paths based on spanning sub-topologies of the network graph. RRL is not tailored for any specific routing or forwarding paradigms. We also propose a set of schemes that are based on link weight manipulation in multiple logical IP topologies. These schemes are tailored for link state based routing in connectionless IP networks. They serve as a supplement to IP full reconvergence in order to provide recovery in a suitable time-scale. Several schemes are developed and optimized according to different properties. We also propose a scheme named IPRT that relies on destination based backup next hops. IPRT bounds the additional state requirements compared to the schemes based on multiple topologies. The schemes are evaluated according to a set of functional properties and critical performance metrics, both in fixed and wireless networks. In addition, the thesis gives a thorough comparison with the most related schemes. 3