Greg Bernstein

IP-centric control and management of optical transport networks

Previous techniques for the management and control of optical transport networks are proving inadequate in todays rapidly evolving multivendor environments. This article examines the issues and challenges involved in developing a standardized optical network control plane. The control of optical transport networks is decomposed into provisioning models, a circuit provisioning process based on signaling, a neighbor and service discovery process, and a topology and resource discovery process. Unique properties and challenges of optical transport networks are explained in the context of these functions.

The optical network control plane: state of the standards and deployment

The notion of an optical control plane has rapidly ascended from being a mere concept to a detailed set of protocol standards developed with broad industry participation. In this article we present a brief overview of optical control plane architecture and the associated protocols. We then examine the business drivers and inhibitors behind the optical control plane effort, the current state of the standards, interoperability status, and the open issues that need to be resolved before widescale deployment of this new technology can begin.

Signaling for fast restoration in heterogeneous optical mesh networks

With the advent of optical mesh networks, certain new protection schemes have been defined. This encompasses both local span and end-to-end path protection. But the implementations of these protection schemes have so far been based on proprietary mechanisms developed by each vendor. This has made it virtually impractical to construct a heterogeneous network with interoperable mesh protection schemes. Also, while the notion of a standard IP-centric control plane for optical networks based on Generalized Multi-Protocol Label Switching (GMPLS) has gained wide acceptance, the work in this area has so far focused exclusively on connection provisioning rather than restoration. This paper defines standard, IP-based signaling protocols for restoration in optical mesh networks. These protocols focus on a new local span protection mode and end-to-end shared protection. The main requirements on these protocols are simplicity and speed. The signaling mechanisms described in this paper are complimentary to the GMPLS provisioning mechanisms.

Standards update: routing for optical networks

We focus on a component of the optical control plane: routing. We give a quick overview of what routing functionality can mean in the optical control plane and compare that with routing in IP networks. We also look at this functionality from the point of view of a carrier running an optical network. We point out some areas of potential disagreement and give an update of the status of optical routing at the various standards bodies.