VMware's next network virtualisation targets: ELEPHANTS and MICE

Nicira guru Casado says SDN is Close Encounters, not Armageddon

VMware's software-defined networking (SDN) Daddy Martin Casado has likened the technique to the film “Close Encounters of the Third Kind”, not the meteor-headed-for-earth scenario of “Armageddon”.

Speaking to The Register at vForum Australia, Casado said he likes the Close Encounters analogy because SDN is already here and running at the likes of Amazon Web Services, Google and Azure, even if they don't expose it to users.

“A large percentage of the world's workloads are doing it already,” he said. “This is a ten year trend that has nothing to do with VMware or Nicira.”

In other words, the aliens are here and we need to get used to it.

'There will always be physical networking,” he added, which rules out the Armageddon scenario. “What we are seeing is functionality like security, billing, visibility and performance optimisation is going to the software layer. It is a new layer between the OS and hardware that adds functionality.”

“I do think that because this is transformative and disruptive, traditional vendors are on their heels, but I think that is because there is a big change happening.”

That change is SDN's ability to greatly reduce the time needed to configure networks, a task he feels consumes too much time and therefore hampers innovation. Big cloud players can't tolerate that and Casado thinks you probably shouldn't either, but does acknowledge that SDN is not for everyone, partly because SDN is new and partly because smaller shops may not need dynamic network configuration.

But Casado thinks the ability for networks to self-configure is compelling because it can mean networks learn how to speed traffic.

“In the data centre there are normally two types of traffic,” he explained. “There is very bursty traffic with very small flows, we call those 'mice'. Then there are very long load traffic, which are 'elephants'.”

“It turns out that for most performance problems you have elephants stepping on mice. If a user perceives a problem you have a very long flow stepping on a short flow.”

With SDN, “One of the things we can do is identify these flows close to the edge. So I can say this is elephant flow and optimise within the data centre fabric, mark it as an elephant flow, identify it as such and make sure it does not step on the mice.”

Casado said that elephants and mice are problems he finds personally interesting at present and are the kinds of thing he is considering as he plans future versions of NSX, VMware's SDN product that reached general availability last week.

Work is of course under way on the new version, but Casado said he thinks future iterations of NSX will not feature much code coming back from the open source version in the hands of OpenStack. VMware's version, he said, will probably outpace its open source spawn, although not for lack fo support: VMware has doubled the number of people working on OpenStack since it acquired Nicira, he said. ®