by some as a possible successor specification. For carrier networks, lambda switching is considered the next wave (see Chapter 7, "All-Optical Networks"). End Notes 1. A comprehensive discussion of SONET was provided in D. Minoli, Enterprise Networking: Fractional T1 to SONET, Frame Relay to BISDN (Boston: Artech House, 1993). 2. Today 10-Gbps OC-192C systems are also being deployed. 3. Stephan Koffler and Lori Franklin. "Optical Networking: A Focus on the Metro Opportunity." First Union Securities, New York, June 2000. Traditional SONET Architectures 4. The excerpt that follows is from Glenn Bischoff's "Promises Made, Promises Kept," Telephony (July 9, 2001). So when ELEC 'X' decided its value proposition was going to be the provisioning of non-oversubscribed bandwidth at guaranteed transport speeds of 100 Mbps for the flat rate of $1,000 per month (including Internet connection), it was prepared for more than a little bit of skepticism. 'It is almost a too-good-to-be-true proposition," acknowledges [Va]. 'But we welcome the skepticism.' [ELEC 'X'] is very specific in terms of the companies it targets for its service: commercial end-users in multitenant office buildings, specifi- cally those that have to transport a large number of high-capacity files such as law firms and financial services/investment companies. [ELEC'X'] looks for buildings that have a comparatively large percentage of these types of com- panies. In addition, a building must have at least 100,000 square feet of office space and 30 tenants for [ELEC 'X'] to consider it a viable prospect. However, the sweet spot is 1 million square feet of office space and 67 customers, says [Ku]: 'We feel very confident we can sell into that building in a very profitable way.' Buildings must also be in central business districts and in close proxim- ity to dark fiber. 'We try to determine where we can build the most cost- effective rings,' says [Ku]. To date, [ELEC 'X'] has found 540 buildings that fit the bill and has signed up more than 3,000 customers for se