Design and Implementation of DSL-Based Access Solutions

SSG Service Models

SSG can provide two flavors of implementation or service models: Layer 2 Service Selection or Layer 3 Service Selection, both of which are discussed in detail in this section.

The main difference between a Layer 3 Service Selection and a Layer 2 Service Selection is that in the case of Layer 2 Service Selection, the user has already identified his final destination before he initiates a PPP session, and that final destination remains the same until that PPP session is active. In the Layer 3 Service Selection model, the user has multiple choices of services (final destinations) that he can select from after he lands into the walled garden (local network) of the NAP or NSP. The user can then select what service he actually connects ...