SDN and the software defined data centre: Opportunities and challenges ahead

James has more than a decade of experience as a tech journalist, writer and editor, and served as Editor in Chief of TechForge Media between 2017 and 2021. James was named as one of the top 20 UK technology influencers by Tyto, and has also been cited by Onalytica, Feedspot and Zsah as an influential cloud computing writer.


Imagine you had just arrived at London Euston railway station and wanted to walk to Leicester Square. A map from a well known search engine provider reliably informs us that it is roughly a 30 minute jaunt, but if you did not have that option, you could ask passers-by for directions ad nauseam at each junction until – assuming you do not get duff advice – you reach your destination.

This represents a good analogy for the state of more traditional networks – ‘move to the next hop in the network and a decision is made’ – versus software defined networking (SDN) with a controller, according to Michael Allen, EMEA VP and chief technical officer of digital performance monitoring company Dynatrace. He sees SDN, and its closely allied brethren, the software defined data centre (SDDC), as the next flavour of virtualisation, but it remains a little out of reach for large enterprises.

“Very, very few enterprises are doing it today, [but] many are looking at it,” Allen tells CloudTech. “It has the eye of the CTO office, it is the next wave of virtualisation, there’s a lot of promise behind it… [but] I have not seen one large enterprise introduction where we’re having to actually plug into an SDN-enabled network. So I think it’s still very much at the hype point.”

This view of the software defined data centre is shared by the analyst houses. A report from Gartner in September argued that, long term, it would be crucial for IT organisations – by 2020, the programmatic capabilities of an SDDC would be required for three in four Global 2000 Enterprises looking to deliver a DevOps and hybrid cloud approach.

Allen makes the comparison with cloud two years ago as to where software defined computing is today. “With cloud, I see so many large enterprises doing that today, putting mission critical platforms on public cloud,” he explains. “That’s where I see SDN today. When we talk about data centre virtualisation, it first started off with rationalisation, and then consolidation of workloads, and then we started to move into the more dynamic nature of it.

“I think today when we’re looking at SDN we’re starting to see more of the static nature of that, VPNs, and the tunnels being set up,” he adds. “The dynamic nature of it in terms of the control, of the intelligence – maybe that’s a couple of years out.”

Recent research appears to back that statement up. A report from 451 Research released last month argued software defined infrastructure (SDI) was a key growth area for the enterprise data centre – yet only one in five organisations polled (21%) said they had achieved SDI. Allen argues the survey results are not particularly surprising, but sounds a note of caution if it could be taken a step further.

“I think still today, we’re just starting to see in the last 12 to 18 months some of the initial SDN players who are kind of startup players now start to be acquired by the larger networking and optimisation players,” he says. “For the enterprises, it’s both a benefit for all of the promise having everything virtualised brings…but if we look at the complexity that dynamic virtualisation or VM migration had on trying to manage that software defined data centre, this for me is probably even worse than the complexity of just virtual machines moving around.

“If they’re in that ‘blueprint’ rigidity that keeps machines sensibly arranged with regards to physical infrastructure, you could have virtual machines running in the same web server, app server, or fabric stack,” Allen adds. “You’re not only dealing with the dynamics of the server virtualisation controllers, but you’re also dealing with the SDN controller’s decisions as well.

“So I think it’s going to be an even bigger headache for people to manage application user experience, application performance, as the network becomes more dynamic and less predictable.”

This is where Dynatrace aims to help in the form of greater visibility in the network. With the release of the latest version of its Data Center Real User Monitoring (DC RUM) software, Dynatrace aims to deliver end user and performance monitoring for software defined networks and, in time, speed up organisations’ transition to more service-oriented IT. The growing trend of shadow IT means the IT department needs to get some power back, according to Allen.

“Because we have visibility on all users, all transactions and all applications, whether it’s internally hosted, cloud hosted or third party, it allows IT to get a little bit back in control,” he explains. “We’re providing visibility getting control of all those services. What’s changed this week? Are there new services the business is using? Where are those services hosted? Are they compliant with corporate policy?

“If organisations put too many machines into a virtual LAN, you create a broadcast domain across the network that can actually end up slowing things down – if that domain is too large and too distributed, then it can cause massive issues for the physical infrastructure,” says Allen. “So providing end user performance visibility…takes those meaningful measures, like having a stopwatch sitting on the edge of the end user, and then when that performance is slowed being able to correlate it, not just to produce data that humans then have to look at, but to automatically do anomaly detection on that data.”

And so back to our intrepid traveller at Euston, who has decided to ditch the walking plan and go to Leicester Square by car, armed with a trusty sat nav. A roadblock has caused the software to recalibrate – and here the analogy provides a glimpse into the future challenges of software defined computing. “When you’re in a traffic jam on a road system, everyone’s sat navs behave the same,” says Allen, “so what might appear a quick route very quickly becomes highly congested – they’re not aware of the other traffic going on. I think that’s going to be a challenge moving forward. We’ve got these hybrid networks where SDN is being rolled in, but it’s not fully governing everything.”

The future of SDN and the SDDC is clearly bright – but there are still a few kinks to iron out before we get there.

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