Announcements over the past several months including VMware’s NSX, HP’s SDN SDK, and others show that Software Defined Networking (SDN) is hitting the mainstream in a large way. Conventional wisdom is that SDN is still early in the “hype cycle”, but a closer looks reveals that SDN may be a very core part of how Amazon’s AWS has managed to achieve the scale it has. Could commercially viable SDN solutions be a way to bridge the gap for competing public and private cloud vendors?
One of the advantages that Amazon’s AWS has held is the ability to massively scale its elastic compute cloud (EC2) with nearly hands-free automation. Amazon, of course, has always been very private about how it does this, but it seems clear that one of the keys has been their substantially customized version of the Xen hypervisor which (among other things) likely has implemented a form of software defined networking (SDN) for a pretty long while. Capabilities such as AWS CloudFormation, security zones, Elastic Load Balancer, and others have clearly shown that much of what used to be network hardware is implemented in their software stack. With VPC, AWS has been a leader in SDN, with strong network isolation (including overlapping IP ranges) that are obviously embedded in the hypervisor and supported by a custom hardware stack. There’s little argument that this has been a huge differentiator for AWS, not just enabling massive scale, but a steady stream of price cuts along the way.