Cisco's IOS (Internetwork Operating System) is the operating system that Cisco has been developing for many years for use in their routers and switches. IOS is a package of routing, switching, internetworking and telecommunications functions tightly integrated with a multitasking operating system. Originally IOS used an integrated kernel, but more recently the new version of Cisco IOS called IOS XR has been released that uses a 3rd party real-time operating system microkernel (QNX). This new kernel offers modularity and memory protection between processes, lightweight threads, pre-emptive scheduling and the ability to independently re-start failed processes.



This book, on the 'Fundamentals' of the operating system is very complete. The first few chapters talk about the basics of the operating system itself including its architecture, infrastructure, installation and the like. The remaining chapters talk more about using the OS. This includes things like security, configuration control, routing and switching.



The book is intended for the individual actively managing a Cisco network and provides a basic understanding and details of its use.