vices use in the local metro access/metro core segment of the network, and (5) the emer- gence of new access and backbone architectures, in particular Ethernet- based wide area network (WAN) approaches. According to these same observers, there will be a "changing of the guard in companies, architec- ture, products, technologies, and business models" going forward. Major recent advances in optical technologies are poised to enable widescale deployment of broadband services. Optical networking and evolving Ethernet WAN technologies have the potential to foster a revo- lution in network design, services, and economics at least at the local metro access/metro core level. New service providers have emerged to apply these evolving technologies and position themselves to deliver new broadband services at the 100-, 1000-, and 10,000-Mbps range in the metro access/metro core portions of the network, as well as end to end, in a cost reduced fashion compared with services provided by the incum- bents. We refer to them as metropolitan area service providers (MASPs) to focus on their role at the functional level. A September 2001 front-page article in Network World magazine stated: AT&T dives into metro Ethernet AT&T will become the first of the big three wide area carriers to enter the Ethernet-based service announcement is significant because it represents the largest carrier embrac- ing a potentially disruptive technology. End-to-end Ethernet could ultimately trash the cost conversions of traditional wide area datacom services, a fact that has caught the attention of many carriers. Metropolitan Ethernet ser- vices offer users an alternative to standard SONET OC-3c or OC-12c. There Copyright 2002 The McGraw-Hill Companies, Inc. Click Here for Terms of Use. Preface are fewer hassles handing off an Ethernet connection to a metropolitan or Ethernet network, and the cost is expected to be lower. There is every reason to believe that Ethernet services will become very popular AT&T is not the first company to offer local Ethernet