On Improving the Efficiency and Manageability of NotVia

This paper presents techniques that improve the efficiency and manageability of an intra-domain IP Fast Reroute (IPFRR) technique called NotVia. NotVia provides IP fast reroute service upon any single link or node failure for all destinations in an intra-domain network. However, it has a significant computational cost to restore its state upon topology changes, which slows the recovery of the IPFRR service itself upon a topology change. NotVia also increases the intra-domain forwarding table sizes, and poses potential obstacles for network management, as routers are unaware of the links (hence the amount of traffic) that they actually protect. This paper proposes techniques that can reduce both the computational costs and the forwarding table entries dedicated to NotVia addresses and that improve the manageability of NotVia. We use simulations to evaluate these techniques on real ISP topologies as well as randomly generated topologies using BRITE. The results show that the computational costs and the forwarding table size increments dedicated to restore the NotVia state are reduced to a fraction of their previous values for large topologies, suggesting that the techniques proposed in this paper make NotVia a more efficient and easy-to-manage technique for practical deployment