CCNA® Cisco Certified Network Associate: Study Guide, Seventh Edition

Using EIGRP to Support Large Networks

EIGRP includes a bunch of cool features that make it suitable for use in large networks:

• Support for multiple ASs on a single router
• Support for VLSM and summarization
• Route discovery and maintenance

Each of these capabilities adds one small piece to the complex puzzle of supporting a huge number of routers and multiple networks.

Multiple ASs

EIGRP uses autonomous system numbers to identify the collection of routers that share route information. Only routers that have the same autonomous system numbers share routes. In large networks, you can easily end up with really complicated topology and route tables, and that can markedly slow convergence during diffusing computation operations.

So what’s an administrator ...