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Inventor of OpenFlow SDN Admits Most SDN Today Is Hype
darthcamaro writes "Every networking vendor today is talking about Software Defined Networking (SDN). The basic idea is that the control of the underlying networking hardware is abstracted by software. Martin Casado helped to come up with the whole topic with his 2005 Stanford thesis (PDF). Eight years later after selling his startup Nicira to VMware for $1.2 Billion, Casado sees the term SDN meaning everything and nothing to all people. From the article: '"I actually don't know what SDN means anymore, to be honest," Casado said. Casado noted that the term SDN was coined in 2009 and at the time it did mean something fairly specific. "Now it is just being used as a general term for networking, like all networking is SDN," Casado said. "SDN is now just an umbrella term for, cool stuff in networking."'"
Certainly not all of them; but I'm pretty sure that the box they are all plugged in to is, pretty much, using a software layer to abstract the ugly details of dumping traffic between them over a really, really, fat internal bus of some flavor.
And, in many cases, a single fiber is(thanks to software) being sliced up into a bunch of little VLANs to create a logical topology that (while it is ultimately constrained by the physical one) is substantially different than the physical topology, especially once you count aggregated port groups, redundant links, and so on.
'SDN' doesn't mean jack in part because everything except your 20 year old 10Mb hub is already doing some amount of software trickery(even dumb switches keep track of which MAC(s) are on which port, and anything with 'managed' in the title can do quite a bit more), with varying levels of ASIC vs. general-purpose-CPU and varying levels of correlation between the logical topology and the physical topology.
There just isn't a nice bright line(at least in terms of real-world use cases, obviously a VM chattering to itself over a loopback interface is 'software' and a passive ethernet tap is 'hardware') between what is 'software defined' and what isn't. They all obviously depend on hardware to execute the software; but the amount of additional logical complexity slopes up surprisingly smoothly.
So the only benefit to "SDN" whatever it is that I can tell is that it will could possibly allow source routing. The existing protocols basically will route your packet the shortest hop way or another under guidance of some other metric, unless you set up the router to do some hacks (I hear). The setting up part is done by a human, a network engineer, and the SDN folks think that it shouldn't be done by a network engineer, it should be done by end point software because the network engineer is a human so he is slow and therefore a lesser being than the software engineer, who thinks he knows better. The other reason is that the router vendors are slow in making features available (who needs testing) or fixing bugs in the routers, so the SDN guys think they can write software that does the same thing better and faster.
One application of being able to source route is to trunk over multiple slow links, which normally won't happen with typical routing protocols which will give you one of the routes, usually the lowest-latency link though that is purely up to configuration. Trunking would give you the whole net's bisection bandwidth. Until someone else wants to do the same thing at the same time. "What, there's other software engineers who have machines connected to the Internet?"
Another is on-demand QoS. The killer app is probably to build a DDoS infrastructure foothold into nation states' critical systems. Imagine having wire-rate SDN routers being able to reflect and replicate from within the network.
From what I can tell it is the idea of having all of the routing centralized at one location with nodes which just accept the commands to route certain src and dst streams. It is different because the software defines the routing on a server in a logical representation for centralized management while the nodes are just really hardware appliances.
It is a nice idea to reduce cost, but in my opinion this is where you would never want to do something like this because it allows way too much power in a central authority.
It would be a Chinese government dream network though and the NSA/CIA would piss themselves that ever happened.
(i.e. In such a system the distributed BGP internet would just go away.)
I am totally against it, and I think everyone will be after they see what the real intent is: To bring network layer control through software to a central authority, which isn't possible right now, and once done, shut it down whoever isn't in the 1%.
-Hack
Got Geometrodynamics? Awe, too hard to figure out? Too bad.