The book is a foundational subject matter reference for network engineers. IOS software management is a key aspect of network design and support that affects availability, security and performance. The book starts with an explanation of the IOS life cycle, hardware support and file naming conventions. The audience will learn an effective methodology for selecting IOS release version and feature set package. The steps include feature set requirements, Cisco Feature Navigator, IOS release version, bug scrub and interoperability matrix. The upgrading of IOS code is more complex now with the additional hardware available and stack configuration. There are step-by-step procedures to upgrade the most common Cisco Catalyst switches and routers. The book explains how to connect to network devices and configuration modes for initial setup. In addition there are standard IOS commands to configure interfaces, system management, campus switching, routing and security. The techniques for troubleshooting IOS problems are discussed that include password recovery and fixing corrupt image files. The most common show commands are listed for managing and troubleshooting devices. There is a CCNA level quiz with 100 questions to summarize the subject matter.