Description: By
default, an interface will be in shut-down state. We need to issue no
shutdown command to bring-up the interface. Notice that the show
interfaces command shows that the line protocol is up indicating
that the interface is now active (sending and receiving packets).
Instructions:
1. view the information about interface serial 0
2. bring serial 0 to no shutdown state
3. Now view the state of the interface serial 0
R1>enable
R1#show interfaces serial 0
R1#configure terminal
R1(config)#interface serial 0
R1(config-if)#no shutdown
R1(config-if)#exit
R1(config)#exit
R1#show interfaces serial 0
