On Nov 6, 2012, at 2:07 AM, yashwanth kp wrote: > But now since the hosts (h0,h1) and hosts(h2,h3) are in different subnets, > can they still communicate? > I tried and they are able to ping each other.. > But i thought since they are in different subnets they will not be able to > communicate.. > So how do i simulate different AS interconnected by switches? > can different SDN based AS interconnect by switches communicate with one > another without the need for an additional component?
Subnets are an aspect of traditional L3 routing. But you have an all-OpenFlow network -- it has no traditional L3 routers in it, so there aren't really any subnets unless you write code to make them. Using the simple learning switch components (e.g., l2_learning), you can stick one OpenFlow island with a controller next to another OpenFlow island with a different controller, and things will just work. This even works with l3_learning. But these work by learning where every individual destination is. To oversimplify things, this doesn't scale that well, so large networks (like the internet) don't work that way and instead work by by aggregating addresses at several levels (e.g., subnets). You can implement similar things in OpenFlow, but you have to write the code for it. I'm not clear on exactly what you mean by an "SDN based AS". Are you trying to reinvent interdomain routing using OpenFlow? Implement an AS in OpenFlow? Link an OpenFlow network in one AS with an OpenFlow network in another AS via a tunnel? Something else? SDN is flexible; you can make networks do all sorts of things if you're willing to write the code... Good luck. -- Murphy
