SDN and Virtual networking hold the key to growing hybrid clouds
While still in its early days, SDN can be an opportunity to actually improve network security
By Brandon Butler | Network World US | Published: 15:30, 19 October 2012
If the OpenStack Summit held this week is any indication, virtual networking is a hot IT topic.
A panel discussion about virtual networking in the cloud featuring representatives from HP, Big Switch and Midokura was packed to the brim. Talks by engineers from eBay and Nicira about their software-defined networking implementations in an even larger conference room were standing room only.
There could be a variety of reasons the topic seems to have piqued the interest of so many of the more than 1,400 attendees at this year's show.
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The latest release of OpenStack (Folsom), for the first time, has a virtual networking component named Quantum fully baked into the code as a core project.
The discussions have not just been about Quantum though - they've been focused more the idea that next-generation networking will be, if it isn't already, an essential part of cloud computing in general.
"To get elasticity in the cloud, you need elasticity of the network." And SDN is the way to do that, says Boris Renski, co-founder of Mirantis, a company that helps enterprises deploy OpenStack-powered clouds.
SDN and virtual network technology are their early days, admits Mike Cohen of Big Switch Networks, one of the growing number of vendors in this emerging landscape. So far, early adopters of SDN have been interested in the technology for two main reasons: First, virtualising the network by abstracting core networking functions from the underlying hardware inherently makes the data centre or network environment more efficient. It's similar, Cohen says, to how server virtualisation made computing more efficient. Second, SDN allows networks to programmatically scale, providing much more agility in controlling the network.
These features have so far appealed most to service providers who are looking to scale VLANs to create more segmented and secure multi-tenant environments, or by large enterprises that need to span different infrastructures but want to use the same networking topology.
For users, this ability to control multiple disparate sites under the same network control opens up one of the chief promises of cloud computing: elastic scaling of applications between an on-premise private cloud and a service's provider's public cloud, creating a hybrid cloud. An abstracted network makes that significantly easier, says Gavin Pratt of HP Cloud Services. This will become a necessity for enterprises truly embracing cloud computing, he says.
In the long term, even as cloud computing continues to popularise, many enterprises will not be comfortable having all of their workloads in the public cloud - they will still have on-premise applications. SDN allows users to be able to manage both of those networks through a common framework. "The implication is you will need a public cloud interconnected with the private cloud, to provide a flex-out capability," Pratt says. "To be able to do that within the same network is a huge opportunity."
SDN can be an opportunity to actually improve network security, too. "The SDN controller has a global view of the network," Cohen notes. That ubiquitous view, combined with the network intelligence being done at the edge, means there are new opportunities for the controller to monitor and enforce security policies across the entire system.
Despite this potential, the panelists on the SDN discussions agreed market adoption has been slow so far. It could take up to three to five years for SDN to be the common networking framework, Cohen says.
As it gets implemented, though, the technology will continue to improve. One area he expects to see future development in is around high-level networking functionality being controlled by SDN controllers. Layer 4-7 functions, for example, have not been as integrated as the virtual networking L2 and L3 functions, at least in OpenStack, he says.