The metro region has enjoyed a great deal of technological attention in the last 18 months because service providers have realized that this region of the network has an enormous unmet need, and the service providers, along with their manufacturer partners, have the wherewithal to address it. The metro business market relies heavily on LAN technology, largely the various flavors of Ethernet (traditional 10-Mbps, 100-Mbps Fast Ethernet, and 1,000-Mbps Gigabit Ethernet) for the transport of corporate data among workers in one or more locations. The problem they face today is the result of changing corporate work models. More and more, the concept of the single, monolithic corporate headquarters building is going away in favor of numerous smaller work locations that are located closer to the customer and closer to suburban areas where employees live, illustrated in Figure 6-13. The need to share information among the people in those locations has not changed (in fact, driven by the awareness of the strategic value of shared information and interest in knowledge management, it may actually be greater), so cost-effective solutions are needed to provide a way to transport Ethernet traffic across the metropolitan area. SONET and SDH have emerged as clear contenders for this responsibility, and manufacturers have announced Ethernet-to-SONET/SDH-to-Ethernet products that meet the demand.

Figure 6-13: The metro environment.