Bandwidth-Efficient Protection Strategies for Multi-Protected Multi-Service Backbone Networks

Robust interoperability for DoD applications requires a robust, survivable backbone network, i.e., one that offers multiple services and that can be subjected to multiple, trans-layer failures and still maintain critical connectivity. One of the challenges in architecting such a network is engineering the required protection against multiple failures that is simultaneously bandwidth- (or cost-) efficient. In this paper, we focus on the landline component of a backbone IP-over-WDM transport network that supports multiple service types to its users, ranging from multi-wavelength optical services to sub-rate IP traffic, all in various protection and QoS categories. One category of the services is their protection level, namely, the number k of network-wide failures a service is designed to withstand. We consider services that are k-protected for a mix of various values k. Assuming the possibility of multiple node and/or link failures, we describe a node-disjoint path protection framework based on protection tiers as well as several strategies for backup capacity sharing that can be used separately or in various combinations to provide protection against multiple failures in a bandwidth-efficient or cost-effective manner. As we illustrate, these strategies when used in combination can provide significant reduction in the protection capacity requirements.