Donal O Duibhir was trying to get me to present at INOG for ages, and as much as I’d love to get to Ireland we always had a scheduling conflict.

Last week we finally made it work - unfortunately only in a virtual event, so I got none of the famous Irish beer - and the video about alternate universes of public cloud networking is already online.

Maximilian Wilhelm had great fun turning my usual black-and-white statements into tweets, including:

Pete Lumbis started his Cumulus Linux 4.0 update with an overview of differences between Cumulus Linux on hardware switches and Cumulus VX, and continued with an in-depth list of ASIC families supported by Cumulus Linux.

You can watch his presentation, as well as the more in-depth overview of Cumulus Linux concepts by Dinesh Dutt, in the recently-updated What Is Cumulus Linux All About video.

After describing Cisco SD-WAN fundamentals and its network abstraction mechanisms, David Penaloza explained the components of Cisco SD-WAN solution and its architecture, including in which plane each element operates and its assigned role in the overlay network.

It’s amazing how many people assume that The Internet is a thing, whereas in reality it’s a mishmash of interconnected independent operators running mostly on goodwill, misplaced trust in other people’s competence, and (sometimes) pure dumb luck.

I described a few consequences of this sad reality in the Internet Has More than One Administrator video (part of How Networks Really Work webinar), and Nick Buraglio and Elisa Jasinska provided even more details in their Surviving the Internet Default-Free Zone webinar.

After setting the stage clarifying the current Cisco SD-WAN deployment scenarios, David Penaloza focused on definitions and fundamentals that must be considered before dealing with solutions that hide and abstract complexity like overlays, routing, and network virtualization from the network administrator.

David Penaloza decided to demystify Cisco’s SD-WAN, provide real world experience beyond marketing hype, and clear confusing and foggy messages around what can or cannot be done with Cisco SD-WAN.

He started the first part of his Cisco SD-WAN Foundations and Design Aspects webinar with a quick look beneath the surface of shiny marketing and corporate slidess.

It’s amazing how many people still believe in Security Fairy (the mythical entity that makes your application magically secure), fueling the whole industry of security researchers who happily create excruciatingly detailed talks of how you can use whatever security oversight to wreak havoc (even when the limitations of a technology are clearly spelled out in an RFC).

In the Networks Are Not Secure (part of How Networks Really Work webinar) I described why we should never rely on network infrastructure to provide security, but have to implement it higher up in the application stack.

When I’ve seen my good friends Christopher Werny and Enno Rey talk about IPv6 security at RIPE78 meeting, another bit of one of my puzzles fell in place. I was planning to do an update of the IPv6 security webinar I’d done with Eric Vyncke, and always wanted to get it done by a security practitioner focused on enterprise networks, making Christopher a perfect fit.

As it was almost a decade since we did the original webinar, Christopher started with an overview of IPv6 security challenges (TL&DR: not much has changed).

After describing the FRRouting architecture, as well as recent performance optimizations and usability enhancements, Donald Sharp concluded the FRRouting webinar with detailed deployment guidelines.

After decades of riding the Moore’s law curve the networking bandwidth should be (almost) infinite and (almost) free, right? WRONG, as I explained in the Bandwidth Is (Not) Infinite and Free video (part of How Networks Really Work webinar).

There are still pockets of Internet desert where mobile- or residential users have to deal with traffic caps, and if you decide to move your applications into any public cloud you better check how much bandwidth those applications consume or you’ll be the next victim of the Great Bandwidth Swindle. For more details, watch the video.

After covering configuration and performance optimizations introduced in recent FRRouting releases, Donald Sharp focused on some of the recent usability enhancements, including BGP BestPath explanations, BGP Hostname, BGP Failed Neighbors, and improved debugging.

After the “shocking” revelation that a network can never be totally reliable, I addressed another widespread lack of common sense: due to laws of physics, the client-server latency is never zero (and never even close to what a developer gets from the laptop’s loopback interface).

After introducing FRRouting architecture, Donald Sharp dived deep into configuration and performance optimizations, including asynchronous data plane, next hop groups, and commit-and-rollback.

After introducing the fallacies of distributed computing in the How Networks Really Work webinar, I focused on the first one: the network is (not) reliable.

While that might be understood by most networking professionals (and ignored by many developers), here’s an interesting shocker: even TCP is not always reliable (see also: Joel Spolsky’s take on Leaky Abstractions).

After a brief overview of FRRouting suite Donald Sharp continued with a deep dive into FRR architecture, including the various routing daemons, role of Zebra and ZAPI, interface between RIB (Zebra) and FIB (Linux Kernel), sample data flow for route installation, and multi-threading in Zebra and BGP daemons.