Supporting physical interfaces up to 155 Mbps, the ATM port adapter (PA-A1) and the Enhanced ATM port adapter (PA-A3) require a large amount of switching performance and bandwidth capacity. Consequently, certain combinations of ATM port adapters and other port adapters can exceed the capabilities of Versatile Interface Processor (VIP2) models that were designed for lower performance and bandwidth applications. Therefore, in some configurations no other port adapter can be installed in the VIP2 when an ATM port adapter is installed.