rvice. Of those cus- tomers, about 60 are currently receiving service. Each city has a hub (except for New York, which has two). Each hub connects to a series of physical rings; each ring connects up to eight buildings. The rings are typically no more than 10 to 15 kilometers in circumference. To make the connections between the buildings and the hubs, [ELEC 'X'] leases metro dark fiber on an indefeasible right-of-use basis for 20 years, with a 10-year option, which [Va], [ELEC 'X']'s vice president of marketing, says gives the company all the rights of owner- ship and saves it money at the same time. In each building, [ELEC 'X'] sets up two OC-48 dense wave division multiplexers in a figure-eight configuration; one wavelength provides capacity of 2.5 Gbps in a clockwise direction, while the other does the same in a counterclockwise direction, without the use of optical amplifiers. The wavelengths are physically diverse and protected at Layer 3. The resulting 5 Gbps of capacity is enough to supply a maximum of 46 customers in each building with non-oversubscribed clear-channel 100 Mbps access back to the hub site. If [ELEC 'X'] signs up more than 46 cus- tomers in a building, all it has to do is drop in a few more wavelengths, says [Ku], the company's chief technology officer, who adds that [ELEC 'X']'s archi- tecture is quite different from that used by other optical Ethernet providers. 'A more typical advanced network configuration would run a single gigabit Ethernet ring consisting of two fibers with a single Ethernet connection that Chapter 3 is shared among a number of buildings,' he explains. 'We are only using one strand of fiber to serve eight buildings, SO we are using our capital very effi- ciently.' In all, it is a pretty simple deal, concludes [Ku]. 'The biggest challenge is getting the laterals into a building,' he explains. 'It is a slow process because it involves getting permits, digging up streets and dealing with regulatory issues. That is the real work in the trenches.' According to [ELEC 'X'],