To overcome the rigidity of the traditional data centre network, software-defined networking (SDN) is emerging as one of the most hyped concepts in IT. As enterprises incline toward network virtualisation and data centre consolidation, and seek greater network efficiency and cost control, SDN is emerging as the ideal solution to underpin the transition, says Research and Markets, which notes that by 2018-2019, 35%-40% of overall network spend will be on SDN.
SDN is intended to support business agility and improve efficiency and productivity, among other things. But because the exact definitions and benefits are poorly understood by enterprises, too many vendors have simply been rebranding old solutions under the SDN banner. But SDN is not just about being programmable and having APIs available.
SDN and software-defined data centres (SDDCs) are different. They are game-changers, which is why there are now many global vendors focusing their R&D on this emerging technology. Software-defined networking and data centres allow enterprises to get more work done in the same amount of space in the data centre, and cuts out the need to continue buying special-purpose hardware. It's only really SDN if it delivers agility, real efficiency gains and productivity benefits.
Getting there
The world is still in the early stages of adoption of the SDDC, with enterprises still assessing which vendor vision to follow and what roadmap to follow to the SDDC.
A major hurdle is the virtualisation of networks. Although administrators have been using virtualised servers and storage for years, virtualising the network raises a whole new series of questions.
Traditional network equipment bundles the decision-making logic (the control plane) and the packet delivery mechanism (the forwarding plane) into a single box.
With new SDN technology, these functions are separated. The boxes still move data, but the decisions are made by software running on general-purpose computers. For years, a fully virtualised network has been considered a legitimate possibility, but there have been concerns over managing state changes, access control lists, and counters in logical networks with thousands of virtual nodes. SDN is proving to be good at solving these particular challenges, making it possible to build fully virtualised networks completely decoupled from the underlying hardware.
Seeing the benefits
SDN relies on well-defined APIs that allow enterprises to customise software to extend its functionality beyond what is available out of the box. For example, load balancing can be handled with software and provisioned in a 'service chain' along with other networking services, such as firewalls. These services run on commodity hardware that can be re-sized as appropriate. The underlying physical network is simplified, and redundant tools can be eliminated because resources can be moved around as needed.
Adjustments to the network can be made in real-time through software applications, rather than having to frequently replace or reconfigure physical devices in the data centre. In addition, logically separate entities can be housed on a single device, even if they have conflicting requirements.
The end result: SDDC
Data centres have enjoyed the benefits of compute and storage virtualisation for many years. SDN brings effective virtualisation to the network, paving the way for the SDDC. In future, says Gartner, expect to see the emergence of software-defined architecture too.
A true SDDC has broad programmability across all elements: compute, storage, and networking. Consumable services are decoupled from hardware and implemented as abstractions that, for all practical purposes, behave just like their old-fashioned physical counterparts. But they're free from old-fashioned physical constraints.
The SDDC delivers benefits in several important areas:
* Today's applications have more complex infrastructure requirements, which can be a challenge when also trying to ensure quality of service. The delicate balance of meeting each requirement without harming another process is improved by the level of abstraction made possible by the SDDC.
* Because resources are provisioned on demand, developers are free to focus on the business functionality of applications without undue concern about whether the network can respond - the network in an SDDC automatically reacts to changing application requirements.
* Combining a more consolidated and centralised control framework on top of commodity hardware means there are fewer specialised physical components that can break down and inhibit operations. It also improves visibility.
* With a reduced need for specialised network equipment, companies employing an SDDC will likely see reduced capital and operational expenditures.
A fully software-defined data centre will be a game-changer for those companies that successfully execute the vision, but it shouldn't really change the end-user experience. Software-defined everything creates abstractions up and down the technology stack that make it easy to swap and replace individual elements.
Just as cloud and big data have reached maturity and widespread deployment as part of an IT strategy, the SDDC is likely to define the corporate network in the years to come. Companies should overlook the growing pains of the technology and start planning how and when to make the transition.
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