TL&DR: The new release of netsim-tools includes unnumbered interfaces, configuration modules, and OSPF configuration.

In mid-March, we enjoyed another excellent presentation by Dinesh Dutt, this time focused on running OSPF in leaf-and-spine fabrics. He astonished me when he mentioned unnumbered Ethernet interfaces being available on all major network operating systems. It was time to test things out, and I wanted to use my networking simulation builder to build the test lab.

Job#1: add unnumbered interface support to netsim-tools.

I also wanted to have OSPF configured on all devices without logging into them and typing like a mad monkey. I was thinking about adding configuration modules (OSPF, BGP, EVPN…) to network topologies for a long while. This was a perfect opportunity to put the framework in place.

Job#2: add support for extensible and configurable configuration modules.

Finally, after implementing the unnumbered interfaces and configuration module framework, it was time to develop a basic OSPF configuration module.

Job#3: add support for OSPF routing configuration. It allows you to configure OSPF process ID, node-level and per-link areas, and link costs.

Building a full-blown OSPF test network became a simple process (details coming in another blog post):

• Describe desired network topology in YAML file.
• Run netlab create script to create Ansible inventory and Vagrantfile.
• Start the lab with vagrant up. Wait… Wait some more…
• Deploy device configurations with netlab initial command. The playbook deploys initial device configurations as well as any configuration modules (OSPF in my example).
• Start doing the real testing instead of wasting time building and configuring a lab.

Finally, no job is finished until the paperwork is done. I probably spent way more time writing the documentation than code, but in the end, it paid off. While “wasting” time on documentation, I figured out (and fixed) a few quirks in the system. I also made parameter inheritance much more flexible than what Ansible inventory groups could do.

Finally, Job#4: Commit, merge, push. Hope you’ll find the new release useful and install and use it ;) – if you do, I’d appreciate hearing from you. You could also open a GitHub issue if there’s something you’d like to see in an upcoming release (no promises, though).

Revision History

2021-07-12

Replaced old CLI commands with netlab CLI introduced with release 0.8.

2021-10-13

A bit of polishing