Every network designer faces two major design obstacles when designing IP routing in a large network:
Designing a scalable solution tuned to the specifics of the selected routing protocol.
Designing a network that works well over switched WAN networks (X.25, Frame Relay, or ATM).
Switched WAN networks pose additional challenges on top of the usual set of problems found in large-scale network design due to their specific technology. All of these networks present a multi-access subnet to a router but offer no additional features, such as multicasting, usually found on the LAN networks.
The scalability issues of EIGRP were discussed in several chapters in Part II, "Designing Enterprise EIGRP ...