A Closer Look at ROADM Contention

ROADMs provide the wavelength-switching capability in the optical layer of most transport networks. As the need for greater network configurability grows, ROADMs continue to evolve to provide greater flexibility. More specifically, ROADMs that provide colorless, directionless, gridless, and contentionless operation are on the roadmap of many equipment vendors and service providers. The first three of these properties are easy to define. ROADM contention, however, can take on many forms, which has led to some misconceptions regarding the contentionless property. We examine ROADM contention in more detail in order to provide greater clarity regarding contentionless ROADMs.