Optical layer survivability - An implementation perspective

This paper looks at several aspects of optical layer protection techniques from an implementation perspective. We discuss the factors that affect the complexity of optical protection schemes, such as supporting mesh instead o f ring protection, handling low-priority traffic, and dealing with multiple types of failures. The paper also looks at how the client layer interacts with the optical layer with respect to protection, in terms of how client c onnections are mapped into the optical layer, and how protection schemes in both layers can work together in efficient ways. Finally, we describe seve ral interesting optical protection implementations, focusing on the ones th at are different from conventional SONET-like implementations.