Plexxi is a start up in the network industry re-thinking networking from the ground up. A Plexxi network is different. It is cabled differently. It is thought about differently. It is integrated to other systems differently. With Plexxi, it all starts with conversations that are occurring on the network. These conversations, or relationships, occur between different systems on the network. These relationships are what Plexxi calls Affinities.
If I can recall a conversation I had with Mat Mathews, one of the Plexxi co-founders, from almost a year ago, he made an analogy comparing a Plexxi network to a Social network. The next few lines try and summarize that conversation and what Mat was conveying to me, and how I still think about Plexxi and Affinities today. Plexxi builds relationships and Affinities just like Facebook does, but with Plexxi, the relationships are all about applications in and between data centers, not between the billions of people in the world. A fun way to think about Plexxi is a network that is socially built, but socially built on communications between servers and other endpoints in the network , in which you can define different levels of importance, priority, security, and overall policy as needed and defined by you and your requirements. If a web server was talking to an application server, an Affinity link can be defined, but more commonly, that is a friend or connection in our world of social networking.
From Lots of Paths to Algorithms and PhDs
Plexxi sells network switches that are inter-connected via optical technology and are physically cabled in a ring topology (as opposed to a spine/leaf architecture). If you have 11 Plexxi switches, all in a ring topology, by leveraging the optical components, you actually get a logical full mesh of switches. No matter the size of the ring, there are MANY (dare I say infinite) ways between any two nodes on the ring. For example, you can go direct between two network switches leveraging a Layer 1 optical path, or potentially another Layer 1 optical path that terminates to a neighboring switch (to where you really want to go) and then use that switch’s MAC table to “switch” the rest of the way. The main take away to realize is – there are lots and lots of paths between any two Plexxi switches in a Plexxi ring. Since there are so many paths between any two nodes, how do you figure out which traffic goes over which path?
Well, this is where highly sophisticated algorithms come into play. Plexxi has a team of PhD mathematicians that also know how to write code, that come up with the algorithms needed to figure out which traffic should go over a particular link, and of course, ensure there is a loop free topology with back up paths ready to go. Who wants that job? The algorithms take into account real time state data learned over time as well as the relationships (affinities) that have been defined and also learned. This is pretty cool stuff and arguably stuff that may be more important than routing protocols in the future.
I’ve written about flow forwarding in the past, which is possible with SDN controller technology, but someone still needs to write the code for the flow forwarding policies. Unless you’re Google or Facebook, you probably won’t be writing your own Traffic Engineering Manager anytime soon. You’ll most likely want pre-defined algorithms --- algorithms that aren’t one size fit all, but algorithms you can implement on the network based on the profiles of applications that are being deployed and the policy you define.
Are algorithms like this the future of traffic distribution?
Note: while this post was not meant to be a detailed overview of Plexxi or their technology, I needed to give a brief overview of Affinities and algorithms and how they are being used by Plexxi to tee up a blog I have wanted to write for a while where I’ll explore the use of Affinities in a non-Plexxi network (forward thinking speculation).
Articles I recommend reading before reading my next post.
ECMP: It’s not all equal, or even normal.
Air Travel, Spine and Leaf style
The Future of Networking: Freaky Deeky Math
And videos to check out:
What is Affinity?
(1) When you know it's time to get into marketing and (2) here