In this lab, we are going to continue configuring our campus network.
We've been asked to use both CDP or Cisco Discovery Protocol and LLDP or Link-Layer Discovery Protocol
to verify links.
So we need to check the links between the devices and confirm that the links are correctly configured
per the diagram. We need to verify which ports are forwarding and blocking in spanning tree
and then we need to optimize spanning tree with core 1 being the root for odd VLANs and core
2 being the root for even VLANs.
So have a look at this topology package trace and makes this easy which links are currently blocking
in spanning tree.
Can you see which ports are blocking notice on call one of these ports or blocking and spanning tree
on access 1.
This port is blocking in spanning tree. Now think about the problem.
If a large amount of traffic was sent from many PCs in VLAN 10 on this access switch to this server.
How would traffic flow? Traffic would have to go across this uplink to Core 2 and then use this single
gigabit 1 0 23 link to core 1 to get to the server.
Now imagine that you had many servers here as well as many PCs on switch 2 and switch 3 trying to
get to a group of servers on the left end side. Let's say they were moving large files.
How would traffic flow? So traffic from all of these PCs in VLAN 10 20 and 30 would end up going
via core 2 and then going across the single link to core 1 to get to these servers.
These links are being blocked by spanning tree so no traffic will go from VLAN 20 to core 1 all the
traffic will go to core 2 to get to the servers on the left end side.
That's gonna be a problem because we're gonna have a bottleneck or an issue on gigabit 1 0
23 this is a gigabit port but all of these uplinks are also gigabit ports and PCs are sending
traffic at gig speeds. So if you have 100 PCs sending traffic to multiple servers this gigabit
1 0 23 link is gonna be over saturated.
In other words, there's gonna be too much traffic for that single link.
So we want to optimize our spanning tree and this topology and ensure that core 1 is the route for odd VLANs
and core2 is the root for even VLANs.
In other words core 1 will be the root for VLAN 1 VLAN 10 and VLAN 30, core 2 will be the root
for VLAN 20 and VLAN 100.
So we're going to split traffic across the core switches.
You also need to configure ether channel on the core switches so that we don't have one of these links
blocking, both of these ports should be forwarding. So to do that we're gonna use ether channel.
We also need to configure IP addresses on the core switches to enable inter VLAN routing.
Here are the IP addresses of core 1.
Here are the IP addresses of Core 2 and you need to configure IP addresses on the access switches in
VLAN 1. In the next lab
after this we'll configure IP addresses in the PCs and verify connectivity in our campus network
to ensure that things are working right.
So this is a big lab.
Are you able to do it yourself
Download the attached packet tracer file and try and configure the lab yourself or you can watch
me in the next video complete this lab.
Best way to learn is to try things so try it.
If you get stuck,
Have a look at to the videos to help you.