most of Cisco's routers. The majority of Cisco routers run the IOS, with its familiar command-
line interface (CLI). Also, some routing cards in other devices run IOS. For example, the Route/
Switch Module (RSM) card for the Catalyst 5000 series LAN switches performs routing
functions and executes the IOS.
the code release process, features added at particular IOS revision levels, and other terminology
that will help you talk to the Cisco Technical Assistance Center (TAC), check out a current
Cisco Product Bulletin describing the Software Release Process. One such example is Product
Bulletin #537 (http://www.cisco.com/warp/public/cc/cisco/mkt/ios/rel/prodlit/537_pp.htm).
Cisco routers and switches more often. In fact, because this book purposefully was written for
an audience that already has some training and experience with Cisco routers, several of the
details in this chapter might already be ingrained in your memory. If you would like more
review, or if you are still new to the IOS, read on--the details in this section are important to
using Cisco routers and switches. This chapter reviews such topics as router components, the
CLI, and how to navigate the IOS command set using Help and key sequences for command
edit and recall.
addition to handling the logic of routing packets, the IOS controls the use of different physical
components, which includes memory, processor, and interfaces. This section of the book
reviews common hardware details.
intended for local administrative access from an ASCII terminal or a computer using a terminal
emulator. The auxiliary port, missing on a few models of Cisco routers, is intended for
asynchronous dial access from an ASCII terminal or terminal emulator; the auxiliary port is
often used for dial backup.