Definition

Over the years, advancement in technologies has improved transmission limitations, the number of wavelengths we can send down a piece of fiber, performance, amplification techniques, and protection and redundancy of the network. When people have described and spoken at length about optical networks, they have typically limited the discussion of optical network technology to providing physical-layer connectivity.

When actual network services are discussed, optical transport is augmented through the addition of several protocol layers, each with its own sets of unique requirements, to make up a service-enabling network. Until recently, transport was provided through specific companies that concentrated on the core of the network and provided only point-to- point transport services.

A strong shift in revenue opportunities from a service provider and vendor perspective, changing traffic patterns from the enterprise customer, and capabilities to drive optical fiber into metropolitan (metro) areas has opened up the next emerging frontier of networking. Providers are now considering emerging lucrative opportunities in the metro space. Whereas traditional or incumbent vendors have been installing optical equipment in the space for some time, little attention has been paid to the opportunity available through the introduction of new technology advancements and the economic implications these technologies will have.

Specifically, the new technologies in the metro space provide better and more profitable economics, scale, and new services and business models. The current metro infrastructure comprises this equipment, which emphasizes voice traffic; is limited in scalability; and was not designed to take advantage of new technologies, topologies, and changing traffic conditions.

Next-generation equipment such as next-generation Synchronous Optical Network (SONET), metro core dense wavelength division multiplexing (DWDM), metro-edge DWDM, and advancements in the optical core have taken advantage of these limitations, and they are scalable and data optimized; they include integrated DWDM functionality and new amplification techniques; and they have made improvements in the operational and provisioning cycles.This tutorial provides technical information that can help engineers address numerous Cisco innovations and technologies for Cisco Complete Optical Multiservice Edge and Transport (Cisco COMET). They can be broken down into five key areas: photonics, protection, protocols, packets, and provisioning.