FOSDEM is a truly unique experience and arguably the best open source conference of the year. It is a weekend event organized by open source enthusiasts to promote the widespread use of free and open source software. Each year, during the semester break at Université libre de Bruxelles, thousands of developers from all over the world gather to share ideas and collaborate on open source software.

FOSDEM is unlike any other conference I have ever attended. It is free and open to everyone. Registration is not necessary, nor is it possible. I had my first FOSDEM experience in 2016 and have attended every year since then. Each year, I strive not only to engage with the community as an enthusiastic participant but also to help with the organization and content of the event. After all, FOSDEM is by the community for the community, and the more you put into the event, the more you will get out of it.

This year presented new challenges. Due to COVID, travel to Brussels and meeting in person, as is typically a highlight of the FOSDEM experience, was of course not feasible. Fortunately, the FOSDEM community responded by rallying to put together a great platform for an online event using a wide variety of open source tools and a lot of hard work. It was amazing to experience how fast the online FOSDEM platform came together and how well it worked. This in itself was a tribute to the open source community and validation of the amazing power of open source software and the community that drives it.

Software Defined Networking devroom

I do not deserve credit for the amazing platform on which FOSDEM was hosted, but I did pitch in as one of the organizers of the Software Define Networking (SDN) devroom. The devroom has had a great lineup of talks by excellent speakers in past years, and it lived up to its reputation again this year. Topics included Kubernetes, VPP, XDP, eBPF, Wireguard, and more.


The abstract, presentation, and recording for each session is available through the SDN devroom. I encourage you to browse them all. However, I’d like to call attention to a few of my personal favorites.

Calico/VPP : All You Can Eat Networking, Bringing Kubernetes Goodness to your Hungriest Workloads

By: Aloys Augustin and Casey Davenport

There are classes of workloads that are notoriously hungry when it comes to networking. Think big data, storage, analytics, 5G, virtual network functions, then encrypt it all at 40Gbps line rates. Kubernetes and the Kubernetes network model are increasingly seen as essential to help manage these workloads at scale. But the cost of containerization and container networking can be hard to swallow for workloads that are often used to having dedicated NICs and physical hardware. The novel approach taken by the team was to cook up a feast that is a fusion of two worlds: combining Calico, the popular cloud native Kubernetes network plugin, with VPP, an ultra fast and scalable user space packet processing software. This talk lifts the lid on what has been cooking and the key ingredients that made it possible to offer an all you can eat buffet for your hungriest workloads.

More info and the complete recording are available.



Fast Wireguard Mesh: VPP + wgsd + wg = ❤, Interconnect your services with taste

By Benoit Ganne

This talks shows how to leverage VPP, wgsd and WireGuard to build a dynamic, fast and secure overlay network to interconnect service nodes wherever they are: on-prem, in public clouds or behind NATs. VPP is one of the fastest and most versatile open-source networking dataplanes running on general purpose CPUs, implementing network services such as routing, bridging, ACLs, cryptography and more. wgsd is an open source project maintained by Jordan Whited that implements DNS Service Discovery for Wireguard endpoints and automatically interconnects them through a mesh of Wireguard tunnels. WireGuard is a new VPN technology created by Jason A. Donenfeld that is gaining popularity thanks to its simplicity.

More info and the complete recording are available.


Optimizing External Kubernetes Traffic with Cloud Native SD-WAN, the Bridge Between DevOps and NetOps Worlds

By Lori Jakab

Kubernetes is becoming the platform of choice for more and more application developers. As applications become more complex and more distributed, they may span multiple Kubernetes clusters, or a combination of Kubernetes and on-premise workloads. While internal traffic within a Kubernetes cluster is handled by the CNI plugin, the external traffic between these workloads, or from workloads to end users, is often carried over a Software Defined Wide Area Network (SD-WAN), which is used for traffic optimization. The Cloud Native SD-WAN (CN-WAN) open source project was created to help SD-WAN deployments identify Kubernetes applications and optimize traffic based on application requirements, thereby bridging together DevOps from the Kubernetes cloud native world with  NetOps from the SD-WAN world.

CN-WAN enables developers to annotate their applications and specifying the type of network traffic generated by the Kubernetes workload. This information is then published into a service registry. The NetOps configuring the SD-WAN can take these annotations and develop network optimization policies with the clear knowledge of the traffic type they intend to optimize.

This presentation describes the components of the solution, the interfaces between the components, and how you can adapt this solution to different SD-WAN products and service registries.

More info and the complete recording are available.


Enjoy, and see you next year?

I am sure you will enjoy these and the rest of the great content in the SDN devroom. I also hope FOSDEM will return to being an in-person event in 2022 and that you join us next year in the SDN devroom for more great talks, lively discussion, and of course… Belgian beer!


Lori Jakab, Aloys Augustin, and Benoit Ganne contributed to this blog. Thank you!

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Charles Eckel

Principal Engineer

Global Technology Standards