SDN's role in the cloud

Software-defined networking offers a problem-free interface between cloud computing and the network.

Read time 4min 10sec

In addition to servers and storage devices, a key building block relied on by cloud computing platforms to deliver services is the corporate network infrastructure.

In order for users to take advantage of the benefits of cloud computing technologies, these platforms need to easily integrate with corporate network infrastructures - and the software systems running on them.

Managing the interplay between the cloud and the network is central to the delivery of data, the management of its flow and the promotion of the all-important technologies underpinning business analytics.

With actual servers and storage devices having been virtualised and moved out of the corporate environment into the cloud, an abstraction layer between the physical network infrastructure and the cloud environment has been created.

This gap has to be effectively managed if the challenges of multi-tenancy and the control of network services are to be successfully met and an application-driven approach to integrating the network and the cloud is to be realised.

The emergence of virtualisation has also placed increasing emphasis on the data centre and members of its management staff, who are tasked with having to create and configure virtual machines remotely, and subsequently, configure network addresses or firewall rules in response.

Cloud concerns

Up to now, approaches such as virtual LAN technologies have been used to address these issues. However, they were heavily reliant on manual policy configuration, which led to management complexity and other efficiency- and support-related issues.

Against this backdrop, software-defined networking (SDN) technology is increasingly seen as the most accepted route to the nirvana of a problem-free interface between cloud computing and the network.

SDN is defined as an approach to network building that allows system administrators to quickly provision network connections on the fly instead of manually configuring policies.

SDN is able to address the simultaneous needs for virtualisation, management, mobility and agility in modern network environments.

The SDN concept centres on the decoupling of the network control system that makes decisions about where data traffic is sent (the control plane) from the underlying system that forwards traffic to the selected destination (the data plane).

SDN control software is able to marshal network resources and target commands at specific devices to initiate the appropriate configurations. Network policy management, security, traffic engineering, access control and other functions can all be addressed through a set of configurable applications in the SDN controller.

SDN thus allows for an entire network to be managed through intelligent categorisation, orchestration and provisioning.

Making sense of SDN

A clear understanding of the various SDN technology models and their objectives is critical if cloud services are to be correctly applied within an organisation, and the advantages of cloud computing optimised.

These include the promise to significantly lower the cost of building and configuring - and reconfiguring - high-capacity networks while dramatically improving their speed, efficiency and availability.

While SDN does have its detractors who claim it is currently too complex a technology, respected industry analysts are predicting massive uptakes in SDN technology by 2016.

One of the reasons for their optimism is that new-generation applications need new service-level responsiveness, implemented instantaneously across huge numbers of network elements, in order to function effectively.

SDN is able to address the simultaneous needs for virtualisation, management, mobility and agility in modern network environments, at the same time tackling the reliable delivery of new applications and services in the cloud.

Currently, the Open Networking Foundation's OpenFlow protocol - a vendor-neutral standard communications interface - and the Linux Foundation's new OpenDaylight project, are two open source initiatives geared to promote SDN on a global scale.

An important SDN advantage is its ability to simplify the work of application developers, who no longer have to get to grips with the intricacies of networking control, but rather use an SDN tool to help with planning the right paths through a network, based on a specific application's requirements.

In future, cloud computing environments controlled by SDN will be maximised for the applications they run with the benefits spilling over into corporate and mobile networks of all sizes.

With the technology rapidly gaining marketplace acceptance, the Open Networking Foundation's vision of SDN as the catalyst needed to transform historic static networks into flexible, programmable platforms is about to be realised.

Today, more industry analysts are recognising the value of SDN's role in assisting network platforms to scale massively to support the enormous data centres and the dynamic, highly automated and secure cloud environments of tomorrow.

Martin May

Regional director (Africa) of Extreme Networks.

Martin May is the regional director (Africa) of Extreme Networks. The author of the book: “Everything you need to know about networking”, he is a leading authority on infrastructure security using NAC, IDS/IPS and other network-based technologies. With experience gained in Russia, Germany, UK, the US and various parts of Africa, he is directly involved with system design and implementation at enterprise level. His emphasis is on the evolution in network architectures brought about by the concept of cloud computing. May hosts regular workshops assisting South African dealers and resellers to understand the implications, complications, opportunities and international trends surrounding the cloud. A proponent of social networking for business, he is active on Facebook and makes extensive use of YouTube.

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