- [Instructor] Every network-connected device
requires IP addressing to transmit information
across an entire network.
Some devices like Layer 2 switches maintain IP addresses
for remote administration,
while Layer 3 devices maintain addressing
for routing packets between subnets.
Most networks utilize IPV4 Addressing
to facilitate this functionality.
I'm going to begin by adding
an IP address to an interface on a router.
I'll start by moving all the way to the interface mode.
As IP addressing for a routed interface
is done directly on the interface itself.
From user exec mode,
I'll enter privileged mode enabled.
From here I'll enter global configuration mode and fig team.
Global config mode allows me
to make configuration changes to the router.
From here, I'll enter
interface configuration mode, interface gi0/1.
I'm now able to apply IPV4 Addresses
for this router's interface.
IP address 192.168.88.55.255.255.255.0
So this command structure is IP address
the IP address followed by the subnet mask.
Cisco routers default to their interfaces.
Being in a shutdown state,
I'll enable the interface by entering no shutdown.
Most commands are negated by simply adding
the word note to the beginning of them.
As you can see,
the console popped up information displaying that
the interface is now up.
I'll return to privileged exec mode
by either typing exit twice
or I can simply enter Control + Z.
From here I'll enter a show command
to first verify the interfaces configuration.
show run interface gi0/1.
I'll get the same information
if I typed show running config,
but this way I don't have to parse through
the entire configuration.
Looking for interface gi0/1 config,
I can get additional information
by typing, show interface gi0/1.
This will not only show my configured IP addressing,
but it will also show the state of the interface
up or down along with counters for traffic and errors.
And finally the speed and duplex of the interface.
With this being alive port on the network,
I can also utilize the Ping command at test connectivity
to the other hosts on the land.
Ping 192.168.88.1.
According to my command, you can see the period where
the ping didn't actually successfully transmit.
That's because it initially has
to do an AARP lookup for that address,
but then the exclamation points showing that it actually
did complete successfully, configuration is indeed good.
That's the ping completed.
IPV4 Address configurations
are very similar on Cisco's switching line,
though there are some minor differences.
Interfaces on some catalyst switches
can operate as either Layer 2 or Layer 3 ports.
This is all controlled with the "switchport" command.
If it is enabled, then it's a Layer 2 interface.
If no "switchport" is enabled on the port,
then it acts as a standard Layer 3 interface on this 35, 50
I can configure port 44 to be a routed port
with IP 192.168.55.1/24
first enable, which I'm already in enable mode.
Then (config)#int fa0/44
no switchport IP address 192.168.55.1 255.255.255.0
for verification, I can enter
the interface show run command, show run interface fa0/44.
It's also possible to assign an IP address directly
to a VLAN on a switch.
This also allows for remote administration
via that interface on a Layer 3 switch.
It also allows routing between sudden it's on various VLANs.
To do this, an engineer creates a logical interface
known as a switched virtual interface
or SVI and assigns a dressing to it
as if it were a physical interface.
This is done quite easily
by simply entering interface configuration mode,
utilizing the desired VLAN ID.
In this example, I'll add IP address 192.168.15.1/24
to VLAN 15, (Config)#int vlan 15.
That interface VLAN command creates the virtual interface.
Now, IP address 192.168.15.1
subnet mask, 255.255.255.0 enter.
Now no shut the interface.
I can now verify the configuration
with show interface vlan 15.
Right next to adding a host name or password,
adding IP addresses are one of the most
basic required skills for anyone pursuing the CCNA.