Upper-Layer Dynamic Interfaces over Static ATM Overview

To create dynamic interfaces over Asynchronous Transfer Mode (ATM), you create the static layers of the interface first, and then configure them to support a dynamic interface by means of autodetection. Figure 1 shows an example of the interface stack for a dynamic IP over ATM 1483 interface.

Figure 1: Configuring an ATM 1483 Interface to Support Dynamic Interfaces

On receipt of a packet, the router creates all dynamic layers above the ATM 1483 layer, starting with the lowest dynamic layer. For example, in the case of a dynamic Point-to-Point Protocol over Ethernet (PPPoE) interface, the router creates the PPPoE interface first, then the Point-to-Point (PPP) interface, and then the IP interface.

If any layer of the dynamic portion of the interface column fails to be created, then the interface creation fails and the connection is denied. All dynamic layers above the ATM 1483 subinterface are destroyed, starting with the highest dynamic layer.

When you configure a dynamic interface, you must assign (or create and assign) a profile to the interface. Profile creation and assignment topics are discussed in depth in Dynamic Interface Configuration Using a Profile.