Abstract
A link failure in a network results in interruption of service for many end users. Currently, routers observing a link failure, recompute their routing tables to find new routes around the failure. However, the network drops packets in the transient period starting at the time at which an attached link fails to the time the routing tables are recomputed. This effect is significant in the high bandwidth backbone networks and more critical when voice calls are supported on IP networks. In this thesis, we aim to reduce the packet losses during this transient period. We propose a simple alternate/deflection routing scheme activated by the routers at the time of link failure until new routes are computed. Each node computes a map for each of the linksconnected to an alternate link, which will be used to forward packets during the transient period when the former fails. The alternate link maps are computed in such a way that deflection of a packet on an alternate link can be done irrespective of the final destination. The proposed scheme will make the backbone networks more robust and help in meeting the Service Level Agreements promised to the ISP's by the backbone network. The thesis presents our proposed scheme of Alternate/Deflection routing. Simulation data is presented to show the performance of our scheme.
Vellanki, Siridhar (2003). Improving service availability during link failure transients through alternate routing. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -2003 -THESIS -V45.