This is one of multiple videos discussing Layer 3 switching. In a previous video I showed you how to
configure the switch for inter VLAN routing.
I demonstrated how to configure multiple interfaces in different VLANs and then enable Layer 3 functionality
on the switch to allow it to route from one VLAN to another.
Another function of a layer 3 switch is to run routing protocols.
So in this example what I'll do is connect the two switches together on gigabit 1/0 and
will enable a routing protocol between these two switches.
In addition, I'll bring another PC into the topology and in this example we'll put this PC into a seperate
VLAN. What I'll also do is make the ports between the switches routed ports rather than switch ports.
So this link will act as a routed link.
In other words, layer 3 link rather than a layer 2 link. I'll start up the additional switch and I'll
configure the third PC with an IP address
and let's say the 192 168 0 subnet and click Save and I'll start that PC up. I'll open up a console
to the new switch.
As well as the new PC.
So the second switch will take a while to boot.
While it's booting I'll configure the first switch in the topology.
So on the first switch interface gigabit 1/0.
I'm gonna use the command no switch port to make this routed port.
The interface has come up now because the other switch has booted. I'll configure an IP address on this
port in the 10 1 10 0 0 range.
So notice now show IP interface brief this port acts differently to the other ports to router port.
So we have the IP address shown directly on the interface.
On the second switch hostname switch 2, gigabit 01 needs to be configured as a routed port.
So interface gigabit
1/0 no switch port IP address 10.1.10.2
ping 10.1.10.1 which is switch 1.
So switch 2 can now ping switch 1 show VLAN brief, switch 2 currently only has VLAN 1 or create another
VLAN let's say VLAN 20 or let's create one called VLAN 192 and then I'll create an SVI
of 192 reconfigure this PC with a default gateway of 192 168 0.1. So IP address 192
168 0.1/24
and I need to no shut this SVI.
So show IP interface brief.
We've now got the IP address configured on SVI 192 but we need to put the physical interface into
that VLAN. So show IP interface brief SVI is configured.
This interface has been configured in VLAN 192 and we can prove that by doing show
interface gigabit 00 switch port it belongs to a 192.
So show IP interface brief, interface has now come u. So PC 3 now should be able to ping switch 2 which
it can but these PCs over here will not be able to ping this PC and vice versa until we enable a routing
protocol between the switches. So on switch 1, I'll enable EIGRP and simply enable it on all interfaces
and disable automatic summarization. I'll do something very similar on switch 2 enable EI
GRP needs to be an autonomous system 100 in other words the same autonomous system as the other router
and disable auto summarization.
We can see that a neighbor relationship is established.
So switch 2 has an EIGRP neighbor relationship with switch 1. So switch 2 should have learnt
about routes from switch 1 which it has learnt about network 10 120 304 050 which are the
subnets on these VLAN interfaces. We can see that by using the command show IP interface brief notice
the IP addresses on the SVIs they were advertised through EIGRP and switch 2 has learnt that.
So in this typology now PC 3 should now be able to ping PC 2 as an example. So here's PC 3 can it
ping 10.1.5.1?
Yes, it can.
What about PC 1 which is 10 121?
Yes, it can.
Let's do a trace route to 10 121.
What we should see is that it hits switch 2 which it does then it should hit switch 1 which it does
and then it should get to the destination which is PC 1 which it does.
So that's an example of how you configure layer 3 switches with routing protocols to allow routes to
be advertised from one layer 3 switch to another.
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I wish you all the very best.