phy the FCC dubbed equal access. Next time you pay a telephone bill, look at the term FCC access charge. Nope, the money doesn't go to the FCC. It goes into the owner of the access facilities. And according to FCC regulations, the owner of the access facilities in each LATA must afford equal access to any inter-exchange carrier (IXC) willing to arrange for a connection between their facilities and the local exchange carrier's (LEC) facilities. On the other side of that equation, equal access means the LEC must offer their subscribers the ability to select their long distance, or IXC. The higher levels in the hierarchy vary, depending on the size and extent of the individual long distance carriers. AT&T operates much as it did before divestiture. Others, such as MCI and Sprint, have flatter or fewer levels in their switching hierarchy. All the long distance carriers have gateways to international networks and their own shares in international transmission facilities. Piecing together two Class 1 Class 2 Class 3 Inter-LATA Traffic Inter-LATA Traffic Inter-LATA Traffic Access Tandem Class 5 ILEC 1 ILEC 2 ILEC 3 ILEC 4 Intra-LATA Traffic Intra-LATA Traffic Intra-LATA Traffic Intra-LATA Traffic FIGURE 5-8 Classical Telecom Hierarchical Architecture 5 NETWORK ARCHITECTURE, FACILITIES, AND SERVICES or more SONET links end to end creates an extension of the physical boundaries of the network with the addition of more links (Figure 5-9). All the layers are extended across the interface. Each layer becomes an extension of itself each time a SONET transmission facility is con- nected to another. Linking two or more in series along a path or route, extends the boundary or domain as defined in the facility specification. Figure 5-9 shows a block diagram of SONET transmis- sion infrastructure linked to provide continuous bandwidth that could be used to provision an E-1/T-1/J1 or E3/DS3/J3 private line. Such a facility could be used as a link in a data communications network or to connect two routers in an inter-network or intr