Virtually all service providers have a large installed base of legacy SONET/SDH equipment from multiple vendors. This equipment is not suited to the dynamic telecommunication networks of today. As spare capacity on networks dwindles and older equipment approaches the end of its service life, operators must decide whether to continue investing in outdated, inefficient equipment that does not meet the requirements of today's packet-based, dynamic networks, or transition to a new mode of operation that helps capture additional market share and drive higher revenue while lowering costs.