Optical Network Control: Architecture, Protocols, and Standards

4.1. Introduction

4.1.1. Overview

With a plethora of natural and man-made disasters that could affect telecommunication links and nodes, protection and restoration of telecommunication services is necessary not only to satisfy regulatory requirements and/or service level agreements (SLAs), but also to provide service differentiation. Before utilizing any particular form of protection or restoration, the time frame for the corrective action and the implications of failing to restore service within a particular time frame should be considered. In [Sosnosky94], Sosnosky reviewed the impact on public switched telephone network (PSTN) customers of progressively longer restoration times. This work is summarized in Figure 4-1.

Figure 4-1. Restoration ...