Concept Exercise Chapter 7 Name:

Date: Class:

Cisco Exercises - Semester 2 - Networking Fundamentals

Chapter 7 IOS Images

Introduction

The default source for Cisco IOS software depends on the hardware platform, but most commonly the router looks to the configuration commands saved in NVRAM. Cisco IOS software offers several alternatives. You can specify other sources where the router should look for software, or the router will use its own fall back sequence as necessary to load software.

Settings in the configuration register enable alternatives for where the router will bootstrap Cisco IOS software. You can specify enabled config-mode boot system commands to enter fallback sources for the router to use in sequence. Save these statements in NVRAM to use during the next startup with the command copy runningconfig startup-config. The router will use these commands as needed, in sequence, when it restarts. However, if NVRAM lacks boot system commands the router can use, the system has its own fall back alternatives. The router will fall back and use default Cisco IOS in Flash memory. If Flash memory is empty, the router will try its next TFTP alternative. The router uses the configuration register value to form a filename from which to boot a default system image stored on a network server.

Concept Questions

Demonstrate your knowledge of these concepts by answering the following questions in the space provided.

Routers boot Cisco IOS software from

• Flash

• TFTP server

• ROM (not full Cisco IOS)

• Multiple source options provide flexibility and fallback alternatives

• Why does the router need an operating system?

• Why might there be different versions of router operating systems?

• Explain the process by which the router locates IOS.

• Explain the configuration register.

• Compare and contrast the boot options for obtaining IOS: from flash memory, from the network, and from ROM.

• Describe the show version command and all the information it tells you.

• Describe the process for creating a software image backup, upgrading the image from a network, and loading a software image backup.

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