The service-switching approach is similar to an IP switching architecture. Instead of switching the IP packets according to the IP routing tables, the switching is done according to the IP service layer. This presents a whole new concept for servicing Internet access.

Figure 8 illustrates this architecture.

Figure 8. The Access Service Switch Concept

As Figure 8 reveals, to enable a flexible service-switching functionality, the service-switch system is designed in two layers:

• the hardware layer—that complies with the first and second layer of the open systems interconnection (OSI) model—i.e., the DSL and Ethernet physical layer and the data link layer (DLL)
• the functional software layers—which implement the service-layer software concept and enable switching to the required functionality by controlling the hardware layer

Figure 9 demonstrates the mechanism that enables such service.

Figure 9. The Service Switch in Action

Once customers launch their browsers for a new service, the traffic is intercepted by the service switch that now controls the user traffic and activity (see "1" in Figure 9). The internal service switch that has HTTP service capabilities replies with a menu/portal that reflects the service profile (ISP selection, bandwidth, billing, etc.) defined by the service provider (see "2"). The user selects the required service by clicking the related requests in the menu/portal and applying a password (see "3"). After an authentication cycle ("4" and "5"), the service switch allocates the desired service (see "6") and creates the connection (see "7"). From then on, the service switch switches the IP packets (green line in Figure 9) according to the service profile. Accounting records are periodically sent to the RADIUS server for billing purposes (see "8").

As it can be seen, the service switch reflects a new dynamic, self-configured, and flexible model for creating a real residential IRB.