Cisco routers are the industry standard, to which all other routers are compared. Whether you love them or hate them, you still must live with them. While they're generally robust and reliable, when a Cisco router breaks someone needs to fix it. If you're in IT, when they say someone they mean you.
This book provides a brief introduction to Cisco routers, with a tight focus on what you need to know to get the router up and working in the shortest amount of time. Reading this book once will give you the knowledge on how your router and internet circuit work. Leaving it on top of the router for reference during a crisis will give you a step-by-step guide to troubleshooting when things go wrong.
Once you understand routers, managing switches isn't much harder. This 2nd Edition will help you upgrade, manage, and operate Cisco switching hardware, from the tiny 12-port models to the monster backbone devices.
Most Cisco books with real technical content are heavy enough to stun a moose with. This book is small enough to read in a couple of hours and light enough to carry around in your laptop bag.