Since the deployment of optical communications networks, carriers have used many mechanisms to protect fiber in the core, because of the large volume of traffic carried in the core, and the affect of a failure on the entire user community. Access links, connecting end users to the core network were not protected because they affected a small number of customers, carried relatively low bandwidth traffic and were less critical. As enterprises use ever growing bandwidth and become increasingly dependent on their network connectivity, they demand protected services. Since fiber breaks can occur anywhere in the network, including the so-called "last mile" carriers are looking today for protection systems for the access and edge network links. This paper focuses on the emerging solutions for this application, detailing the key criteria for selecting fiber protection switches: optical performance and cost effectiveness (important because the cost must be amortized over a small number of customers). It discusses
solutions to the various access network topologies and common protection schemes.
A. Queller, A. Queller,
"Protecting fiber in the access link", Proc. SPIE 6021, Optical Transmission, Switching, and Subsystems III, 60213B (9 December 2005); doi: 10.1117/12.636731; https://doi.org/10.1117/12.636731