In our lab, we will use VIRL, as in the previous chapters, because our goal is to illustrate a network topology. We will use five IOSv network nodes along with two server hosts:

If you are wondering about my choice of IOSv as opposed to NX-OS or IOS-XR and the number of devices, here are a few points for you to consider when you build your own lab:

• Nodes virtualized by NX-OS and IOS-XR are much more memory intensive than IOS
• The VIRL virtual manager I am using has 8 GB of RAM, which seems enough to sustain nine nodes but could be a bit more unstable (nodes changing from reachable to unreachable at random)
• If you wish to use NX-OS, consider using NX-API or other API calls that would return structured data

For our example, I am going to use LLDP as the protocol for link layer neighbor discovery because it is vendor-neutral. Note that VIRL provides an option to automatically enable CDP, which can save you some time and is similar to LLDP in functionality; however, it is also Cisco proprietary:

Once the lab is up and running, proceed to installing the necessary software packages.