|Authors||T. Cicic, A. F. Hansen, A. Kvalbein, M. Hartmann, M. Menth, R. Martin, S. Gjessing and O. Lysne|
|Title||Relaxed Multiple Routing Configurations: IP Fast Reroute for Single and Correlated Failures|
|Afilliation||, Communication Systems|
|Publication Type||Journal Article|
|Year of Publication||2009|
|Journal||IEEE Transactions on Network and Service Management|
Multi-topology routing is an increasingly popular IP network management concept that allows transport of different traffic types over disjoint network paths. The concept is of particular interest for implementation of IP fast reroute (IP FRR). First, it can support guaranteed, instantaneous recovery from any single link or node failure as well as from many combined failures. Second, different failures result in routing over different network topologies, which gives better control of the traffic distribution in the networks after a failure. The authors have previously proposed an IP FRR scheme based on multi-topology routing called Multiple Routing Configurations (MRC). In this paper we present an enhanced IP FRR scheme which we call ``relaxed MRC'' (rMRC). rMRC simplifies the topology construction and increases the routing flexibility in each topology. This makes rMRC better suited for successful load distribution after failures and handling of correlated failures. According to our experimental evaluation, the number of backup topologies required to provide protection against the same failures is reduced in rMRC compared to MRC, hence reducing state in routers. In addition, the backup paths are shorter, and the link utilization is significantly better. The paper also presents how rMRC can provide recovery from multiple correlated failures without compromising much on the number of backup topologies required and the path lengths.