Resilience for IP-over-DWDM backbone networks

Given the extensive growth in Internet traffic and increasing emphasis on service quality, one of the most crucial elements of IP backbone network design is to provide resilience to serious failures such as fibre-optic cable breaks. In previous years, the unit of bandwidth granularity for many IP backbone networks has grown from STM-1 (155 Mbit/s) through to STM-16 (2.4 Gbit/s), with STM-64 (10 Gbit/s) backbone circuits becoming prevalent. The increased concentration of traffic makes the IP backbone extremely vulnerable to failure, meaning a key challenge is to engineer embedded resilience into the network. This paper considers such issues and discusses various trade-offs associated with different levels of protection in an IP backbone network.