In the previous video in this topology
the switches were configured with host names
and unused interfaces were shutdown.
So as an example, switch 4 was given a name of S4
and any unused interfaces were shut down on the switch.
The VTP mode was set to transparent and VLAN 10 and 20
were created on the 4 switches in this topology.
Router 1 and router 2, acting as PCs in the topology
were configured with IP addresses on their FastEthernet interfaces.
Router 3 was also configured with an IP address
in FastEthernet 0/0 as well as on FastEthernet 0/1.
The switches will also configure with IP addresses.
So the access layer switches were configured
with IP addresses in the management VLAN.
Which in this example is gonna be VLAN 1 the default.
The core switches were configured with 3 IP addresses.
1 in VLAN 1, 1 in VLAN 10 and 1 in VLAN 20.
In this video, the interfaces on the switches will be configured as either trunks
so these ports will be configured as trunks or access ports
So on the access switches, gigabit 0/2 on both switch 3 and switch 4
will be configured as an access port in the relevant VLAN
Once we’ve got this configured properly, the routers acting as PCs
should be able to ping the core switch IP addresses in the same VLAN.
So switch 1 core switch.
This interfaces gonna be configured as trunk ports.
This interface will be configured as an access port in VLAN 1
which is connected to Solarwinds network performance monitor.
In a later video, I’ll show you how to integrate NPM with this topology
using SNMP so that we can manage these switches and the routers using SNMP.
So switch 1, first thing to check is which VLANs are configured on the switch.
So I configured the commands sh vlan or sh vlan brief
sh vlan brief shows me that vlan 1 is configured.
And all these interfaces belong to VLAN 1, VLAN 10 and VLAN 20 have been configured
but no interfaces have been put into VLAN 10 or VLAN 20.
I could also do a command such as sh int gigabit 0/0 switchport
So here’s the command
and its shows me that this interface g0/0 is enabled as a switchport.
In other words, it’s a layer 2 interface not a layer 3 interface.
So it’s acting as a layer 2 switch interface rather than as a routed interface.
This switch is going to be negotiating the encapsulation
as well as the negotiation of trunking.
In other words, it’s using dynamic trunking protocol or DTP.
Now rather than using that were going to statically configure the trunk port
and access ports rather than relying on DTP.
It’s recommended that you disable DTP.
The access mode VLAN is 1.
In other words, if this port negotiates to be an access port
it’s gonna be in VLAN 1 and the native or untagged VLAN
on the trunk port when it's a trunk port will be in VLAN 1.
We can see other information here including the VLANs allowed across the trunk.
All VLANs are allowed by default.
Pruning is enabled for VLANs 2 to 1001
so conf t rather than configuring each interface individually
I’m gonna configure a range of interfaces.
So interface range gigabit is 0/0 to gigabit 0/0 - 3
so I’m gonna configure this interface
this interface, this interface, and this interface to the range command.
Notice what happens when I trying change the mode to trunk.
I’m told that the command is rejected
an interface whose trunking capsulation is set to auto
cannot be configured to trunk mode so the command failed on gigabit 0/0.
On some Cisco switches including this one
you need to specify the trunk encapsulation
before you change the mode to trunk.
this switch supports 802.1Q and ISL
and can negotiate encapsulation with the neighbor
so I want to explicitly set the encapsulation to dot1q
and now I’ll be able to type switchport mode trunk and then I can type end.
So let’s look at how the interface is changed.
Before I do that notice interface VLAN 10 and interface VLAN 20 have come up.
These are SVIs on the switch.
So sh int g0/0 switchport
You can see that the administrative mode is trunk
and the current operational mode is trunk.
I have manually or statically set this interface to trunk.
Previously the administrative mode was dynamic auto
the interface was using dynamic trunk protocol or DTP
to negotiate with neighboring switches to set up trunking.
But now we’ve configured it to manually trunk.