ing into their own. Some of these examples have been cited above, but here we will take a closer look at each one. Incumbent Local Exchange Carriers (ILECs). ILECs include both independent "telephone" companies and the Regional Bell Operating Companies (RBOCs). In other words, these are the companies that built and own the local network infrastructure that provides the basis for most access to the Internet and other communications services. They own the copper lines, or "local loops" that serve the majority of businesses and residences - a phenomenally valuable commodity. They also control most of the central and end offices that house the switching and multiplexing equipment, distribution frames and other key elements that make up the serving infrastructure. Taken together, these elements represent the choke point for access to network services of all kinds, including the Internet. These ILECs, which held regional monopolies before deregulation, now face increasing competition from other IICs, and have been ordered to open their networks and essentially help their new competitors grow. Thus, they are a critical part of the Internet infrastructure supply chain that will be discussed in Chapter three. Their service offerings span everything from "plain old telephone service" (POTS) to complex data networking, DSL, and in some cases, video. They are not, however, permitted to offer any kind of long-distance services without approval from state public utility commissions. The requirements to gain this approval, also to be discussed in Chapter 3, are based on OSS capabilities. Some ILECs have received approval to offer long distance services in limited regions, but only after rigorous and costly OSS testing. Examples of ILECs include Verizon, SBC and BellSouth. Interexchange Carriers (IXCs) and Backbone or Network Service Providers (NSPs). The IXC and NSP groups overlap, though they aren't always the same. An IXC is what we generally call a long distance provider. There are many different types of companies that prov