ipSpace.net blog

After I published the updated netlab topology graphs article, Samuel K.

I’m too old to be fighting with windmills, but sometimes I have to get a rant off my chest.

Like OSPF and BGP, IS-IS contains a simple mechanism to authenticate routing traffic – IS-IS packets can include a cleartext password or an MD5- or SHA hash.

Someone approached me after my NOG.HR netlab presentation and said: “wouldn’t it be great if we could just start the lab from an example topology published on GitHub?”

Is it possible to deploy Precision Time Protocol across a country-wide WAN network and reach nanosecond-level synchronization between cities?

Last week, I explained how to generate network topology graphs (using GraphViz or D2 graphing engines) from a netlab lab topology.

When I was writing a blog post, I needed a link to the netlab lab topology documentation, so I searched for “netlab lab topology” (I know I’m lazy, but it felt quicker than navigating the sidebar menu).

I wrote about the optimal BGP path selection with BGP additional paths in 2021, and I probably mentioned (in one of the 360 BGP-related blog posts) that you need it to implement IBGP load balancing in networks using BGP route reflectors.

I always ask engineers reporting a netlab bug to provide a minimal lab topology that would reproduce the error, sometimes resulting in “interesting” side effects.

During integration testing, I find unexpected quirks in network devices way too often.

netlab release 25.09 introduced numerous graphing enhancements and a new graph type (IS-IS graphs), so I decided to write a series of blog posts explaining how you can generate graphs from netlab lab topologies.

On September 9th, the ansible release 12.0 appeared on PyPi.

IS-IS does not use IPv4 or IPv6, so it should be a no-brainer to run it over IPv4 unnumbered or IPv6 LLA interfaces.

Since time immemorial, I have used the ip host router configuration command to get host-to-IP mappings in networking labs without going through the hassle of setting up a DNS server.