Attilla de Groot

Author Archives: Attilla de Groot

EVPN on the host for multi-tenancy

As an SE at Cumulus, I’m involved in designing and implementing data center networks for MSPs and enterprises. While doing so, I have to be aware of how Cumulus can integrate our solution with solutions from multiple other vendors depending on the solution that is needed. While I’m not a software engineer or protocol developer myself, I’m interested in deploying these solutions in real world environments. Cumulus Linux is a standard Linux environment, and as a company, we use and develop on open-source tools and solutions. In this blog, I would like to address a common requirement in data center networks: multi tenancy, and how this can be achieved in the Linux ecosystem, open-source software and various other tools, specifically with EVPN on the host.

Multi tenancy use-cases

There are two major ones that are often deployed:

• Virtual machines
• Container environments

Virtual machines in the Linux ecosystem are mostly KVM deployments and in many cases deployed in combination with Openstack. There are different multi tenant architectures, but the most common one is to build an overlay network with VXLAN between the hypervisors. To reach resources outside the specific tenant environment, dedicated network nodes are being used.


While this architecture is Continue reading

SHA 2017 – bringing 100 gigabit to the tent

Every 4 years since its start back in 1989, a hacker/security conference takes place in the Netherlands. This summer, the eighth version of this conference, called Still Hacking Anyway 2017 (, will run between the 4th and 8th of August. The conference is not-for-profit and run by volunteers, and this year we’re expecting about 4000 visitors.

For an event like SHA, all the visitors need to connect to a network to access the Internet. A large part of the network is built on Cumulus Linux. In this article, we’ll dive into what the event is and how the network, with equipment sponsored by Cumulus, is being built.

What makes SHA 2017 especially exciting is that it is an outdoor event. All the talks are held in large tents, and they can be watched online through live streams. At the event site, visitors will organize “villages” (a group of tents) where they will work on several projects ranging from security research to developing electronics and building 3D printers.

Attendees will camp on a 40 acre field, but they won’t be off the grid, as wired and wireless networks will keep them connected. The network is designed Continue reading