Loop-free alternates and not-via addresses: A proper combination for IP fast reroute?

The IETF currently discusses fast reroute mechanisms for IP networks (IP FRR). IP FRR accelerates the recovery in case of network element failures and avoids micro-loops during re-convergence. Several mechanisms are proposed. Loop-free alternates (LFAs) are simple but cannot cover all single link and node failures. Not-via addresses can protect against these failures but are more complex, in particular, they use tunneling techniques to deviate backup traffic. In the IETF it has been proposed to combine both mechanisms to merge their advantages: simplicity and full failure coverage. This work analyzes LFAs and classifies them according to their abilities. We qualitatively compare LFAs and not-via addresses and develop a concept for their combined application to achieve 100% single failure coverage, while using simple LFAs wherever possible. The applicability of existing LFAs depends on the resilience requirements of the network. We study the backup path length and the link utilization ...

• Type: Journal
• Year: 2010
• Where: CN
• Authors: Michael Menth, Matthias Hartmann, Rüdiger Martin, Tarik Cicic, Amund Kvalbein
• Keywords: CN 2010, Discusses Fast Reroute, IP FRR, LFAs