Review of Cisco IOS for Routers and Switches, CCNP Certification in Delhi Gurgaon India

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As small networks grow and become more complex, greater functionality and control over
network components, delivered through more sophisticated network devices such as switches
and routers, become critical. Most Cisco hardware platforms implement Cisco IOS Software,
including switches and routers. This software enables network services in Cisco products,
including carrying the chosen network protocols and functions, controlling access and
prohibiting unauthorized network use, and adding interfaces and capability as needed for
network growth. You use the command-line interface of the Cisco IOS Software to enter the
configuration details into the Cisco switches and routers that implement the network
requirements of an organization. To understand how to configure the more complex protocols
and functions of Cisco routers and switches, you need to understand the basics of IOS Software.
This chapter briefly reviews some of the key elements of the Cisco IOS Software, provided as
an aid for the configuration details in this book. The chapter is in no way intended to be
comprehensive and assumes that the reader has Cisco IOS familiarity or has completed the
Interconnecting Cisco Network Devices (ICND), Part 1 materials.
If you find this chapter to be lacking or you do not feel comfortable with the commands and
content presented here, please refer to Authorized Self-Study Guide: Interconnecting Cisco
Network Devices, Part 1 from Cisco Press.
 Objectives
Upon completing this chapter, you will have reviewed how to configure and manage a Cisco IOS
device. This ability includes being able to meet the following objectives:
■ Implement a basic switch and router configuration
■ Understand the modes and features of Cisco IOS
Cisco IOS Software is implemented on most Cisco hardware platforms, including switches and
routers. This software enables network services in Cisco products, including carrying the
chosen network protocols and functions, and adding interfaces and capability as needed for
network growth.

This is designed as a review of prerequisite knowledge. It is a review of the Cisco IOS
command-line interface (CLI) structure and the Cisco IOS commands used to create a basic router
and switch configuration. You will use these commands in an introductory lab that will serve as
the initial configuration for all the subsequent lab activities.
Cisco IOS CLI Functions
Cisco IOS Software uses a CLI as its traditional console environment to enter commands. This
section reviews the functions of the Cisco IOS CLI.
Although Cisco IOS Software is a core technology that extends across many products, its
operation details vary depending on the internetworking devices that are involved. To enter
commands into the CLI, type or paste the entries within one of the several console configuration
modes. In terminal configuration mode, each configuration command entered is parsed as soon as
you press the Enter key.
If the syntax has no errors, the command is executed and stored in the running configuration, and
it is effective immediately, but the command is not automatically saved to NVRAM.
Cisco IOS Software uses a hierarchy of commands in its configuration-mode structure. Each
configuration mode is indicated with a distinctive prompt and supports specific Cisco IOS
commands related to a type of operation on the device.
As a security feature, Cisco IOS Software separates the EXEC sessions into the following two
access levels:
■ User EXEC: Allows access to only a limited number of basic monitoring commands.
■ Privileged EXEC: Allows access to all device commands, such as those used for
configuration and management, and can be password-protected to allow only authorized users
to access the device.