Carrier Network Architectures and Resiliency

Abstract

In this chapter we investigate carrier network architectures, and how and where resilience is provided by commercial telecommunications carriers in today’s optical networks. Much of the content is generally unpublished and we provide the reader a unique insight into this topic through our privilege of working for decades on the inside of different telecommunications carriers. To provide a fuller understanding of this complex topic, we first describe the typical partitioning of terrestrial networks into their metro-access, metro-core, and intermetro segments and then describe the multilayered structure within each of these segments (Sect. 11.2). Within these constructs, we describe where and how network resiliency is provided against a modeled set of potential outages and other network impacting events (Sect. 11.3). To better understand how the resiliency techniques deployed in various layers and segments are engineered, we discuss how end-to-end services are pieced together across these segments to provide their needed network quality of service and availability. Finally, to even better understand why today’s network resiliency techniques have been deployed, we take the reader through a historical evolution of how and why key resiliency technologies and methodologies were developed and deployed, including why some phased out (Sect. 11.4).