Software Defined Networking (SDN)
By Wray Castle
SDN (Software Defined Networking) is an approach to data networking in which the control functions are decoupled from the physical infrastructure. This allows network administrators to support a dynamic, manageable and cost-effective network making it ideal for the high-bandwidth nature of today’s applications.
SDN addresses the fact that the static architecture of conventional networks is not suited to the dynamic computing and storage needs of modern data centres, campuses, and network operator environments.
A communications protocol known as OpenFlow is considered as an enabler of SDN. OpenFlow enables remote controllers to determine the path of packets through the network of switches and routers. This separation of the control from the forwarding allows for more sophisticated traffic management than is possible using traditional methods. OpenFlow allows switches and routers from different manufacturers (often each with their own proprietary interfaces and programming languages) to be managed remotely using a single, open protocol. OpenFlow allows remote administration of a switch’s packet forwarding tables, by adding, modifying and removing packet matching rules and actions.
The key computing trends driving the need for a new networking concept include:
- Changing traffic patterns: Applications that commonly access geographically distributed databases and servers through public and private clouds require extremely flexible traffic management and access to bandwidth on demand.
- The ‘consumerisation of IT’: The BYOD (Bring Your Own Device) trend requires networks that are both flexible and secure.
- The increase of cloud services: Users expect on-demand access to applications, infrastructure, and other IT resources.
- ‘Big data’ means more bandwidth: Handling large data transfers requires massive parallel processing that is fuelling a constant demand for additional capacity and ‘any-to-any’ connectivity.