An efficient link protection scheme for link-state routing networks

To enhance the network reliability without incurring significant extra overhead, we propose a novel link protection scheme, Hybrid Link Protection (HLP), to achieve failure resilient routing. Compared to previous schemes, HLP ensures high network availability in a more efficient way, and also provides other features such as load balancing. HLP is implemented in two stages. Stage one provides Multiple Next-hop Protection (MNP), where only one single Shortest Path Tree (SPT) needs to be constructed on each node to find multiple next hops for any destination. Stage two provides Backup Path Protection (BPP), where only a minimum number of links need to be protected, using special paths and packet headers, to meet the network availability requirement. We evaluate these algorithms in a wide spread of relevant topologies, both real and synthetic, and the results reveal that HLP can achieve high network availability without introducing conspicuous overhead.