Software-defined Networks: The Way of the Future?
The future of network optimization could lie with a concept that’s starting to gain some momentum in IT circles, namely software defined networking (SDN). It promises a much greater degree of flexibility for fitting networks more closely to business and mission needs than current hardware “tweaks” allow.
“SDN enables you to be more flexible in how you assign resources, make decisions about network traffic and, in some cases, even allows you to go down to the packet level and prioritize things there,” said Shawn McCarthy, research director for IDC Government Insights.
In SDN, the control and data planes, tightly integrated in regular networking configurations, are decoupled. That allows decisions about where the traffic is sent — something that’s governed by the control plane — to be made separately from the data plane, which physically forwards that traffic to its destination. Network administrators can control network traffic centrally, using software hosted on a separate server, without needing to physically access the network switches.
This enables network control to become directly programmable and the underlying network infrastructure to be abstracted for both applications and network services, according to the Open Networking Foundation, an industry group that is leading the development of SDN protocols and standards.
The resulting architecture “is dynamic, manageable, cost-effective and adaptable, making it ideal for the high-bandwidth, dynamic nature of today’s applications,” it said.
The deterministic nature of current networks makes it a complex and time-consuming task to add or move devices or to implement network-wide policies to respond to changes in user demand, and it’s hard to quickly scale such networks to meet fast-changing needs. That makes them increasingly unsuited to deal with current trends such as bring-your-own-device (BYOD), cloud computing and the “mega datasets” involved with big data, which all require very flexible network response.
All of that points to the need for a “new network paradigm,” the foundation said, which SDN is expected to fulfill.
Some government organizations are at least beginning to look at the issues surrounding SDN. In June, for example, the Defense Advanced Research Projects Agency (DARPA) gave Indiana University, which has one of the world’s largest SDN test beds, $910,000 to look into the critical issues and vulnerabilities associated with SDN.
“[SDN] can make networks more secure, reliable and more manageable,” said Professor L. Jean Camp, who will lead the Indiana team. “However, if the security in these networks is not done well….attacks could (also) be more affordable, more reliable and easier to manage.”
Resistance to SDN is to be expected, said Tim Braly, federal distinguished architect and senior systems engineer at networking company Brocade. That’s not least because moving the entire control place out of all devices in the network to a single set of controllers is “a big leap of faith.”
Brocade tackles the problem with a hybrid approach where traditional switching and routing can co-exist with SDN rules so that agencies can test and deploy SDN on the same hardware, and gradually build confidence in the technology. For example, he said, an agency simply can turn off the network optimization the SDN controller is providing and rely on the network hardware to be able to continue to work as it did prior to adding SDN.
But, so far, SDN is clearly in an early adopter phase, though network service providers are beginning to include some SDN solutions in their product offerings, and companies such as Google and Facebook are using SDN to help them cope with wide-ranging user demands on their services. Broader use will take time to develop, however.
“It’s early, early days yet for SDN,” said John Burke, an analyst with Nemertes Research. “Our data indicates that maybe 11 percent of US companies will have SDN in place by the end of this year, and all of it at this point will be in the data center.”
Government is obviously paying some attention to SDN, however. In a recent survey of 251 federal, state and local IT professionals conducted by the 1105 Government Information Group, nearly a quarter of the respondents said their agencies had either installed or were transitioning to SDN. Another 63 percent said their agencies were investigating or already planning for the technology.
Many agencies, under continuing budget pressures, might opt not to go with SDN just yet, Burke said. However, if they bought a traditional network optimization solution today and assumed a five-year tech refresh cycle for that, he said, “then the next time they should definitely consider the effect SDN could have on their (network) operations.”