13.1 The command line and operating system
You were introduced to the Cisco CLI (command-line interface) in an earlier session, but you may have met some things there that you found a little baffling. In this part you’ll look at the CLI in greater detail and unravel some of its mysteries.
Watch the video below, which is a little over 3 minutes long. This video introduces you to the Cisco operating system and explains what happens when it is booted up.
Activity 1 Think about
1. The following output shows part of a response to the command show ip interface brief. Explain what is meant by the term ‘unassigned’ in the IP address column.
Router#show ip interface brief
Interface IP-Address OK? Method Status Protocol
GigabitEthernet0/0 192.168.1.2 YES manual up up
GigabitEthernet0/1 unassigned YES unset administratively down down
GigabitEthernet0/2 unassigned YES unset administratively down down
Vlan1 unassigned YES unset administratively down down
From the output, you should have noticed that for the interface GigabitEthernet0/0 there was an IP address in the ‘IP-Address’ column. From this you should have been able to deduce that ‘unassigned’ simply means that an IP address hasn’t yet been configured on those interfaces that ‘unassigned’ appears alongside.
2. Which of the following are Cisco IOS functions?
Checking the router hardware
Loading the config file
Sending a ping to all connected devices
Loading any default settings if there is no config file
Enabling a config file to be created and saved
Warning the user of any security threat.
The correct answers are a, b, d and e.