The introduction of new applications that require high bandwidth, high service availability and reliability has generated many researches in the design of efficient survivable Wavelength Division Multiplexing (WDM) networks in order to respond to the growing demands of quality-of-service in telecommunication networks. Various design methods of survivable WDM networks have been proposed in order to increase the reliability of optical networks and thus their availability. Pre-configured and reserved protection capacity is the most widespread approach, and involves a backup protection plane that will be used in case of a failure in the network. In order to minimize the investment in protection capacity and meet the targeted resiliency, a decisive design concern is to minimize the required spare capacity budget to provide 100% protection against any single link failure.

In this paper, we explore the idea of designing protection planes using structures (called p-structures) with different shapes, each with its specific recovery delays, management overhead to recover from failure, and scalability warranty, as to better answer the various required qualities of services while addressing the different protection performance and efficiency parameters. While doing so, we propose a unified framework for the pre-planned protection design using p-structures, drawn after a general shapeless p-structure scheme, from which we can derive all the pre-configured protection structures already studied in the literature. We quantitatively compare all the already studied pre-planned protection structures under asymmetric traffic, among themselves and with the shapeless p-structures. Comparisons are made possible thanks to a unified column generation modeling. It enables an analysis of the pros and cons of the different pre-planned protection schemes.