Book excerpt: Authorized Self-Study Guide: Building Scalable Cisco Internetworks (BSCI), Third Edition, is a Cisco-authorized, self-paced learning tool for learning how to design, configure, maintain, and scale routed networks that are growing in size and complexity. This book also provides complete coverage of the BSCI exam topics, and supplemental online appendixes include helpful aids, background material, supplementary details, and a summary of the Cisco IOS router commands used.