It feels like 2006 once again: vendors are creating fanciful and colourful presentations about software defined networking (SDN) and operators are discussing the need to move from silos to horizontal platforms and networks. In a way, almost the same story was told 6 years ago for IMS, but deployments were far smaller than expected. So is SDN following the footsteps of IMS?
Before answering this question, it’s worth looking at the telco SDN story from the beginning and why the market is a particularly interesting – and ripe – environment for SDN.
What is telco SDN?
Telco SDN seems to be everything that is described by the following mantra: network elements implemented in software running on commoditized IT platforms. Each vendor has a different implementation, strategy and even definition of SDN, and there seems to be confusion in the market regarding both the actual deployment of SDN in the telco network and the value proposition of the new technology.
For example, one vendor claims that in a true SDN, every element in the network needs to run in software (as far out as the antenna), while other vendors consider that an SDN should be implemented in the data centre for control/data plane abstraction.
In the IT domain, SDN largely refers to OpenFlow (although SDN is theoretically a much broader concept), where the control and forwarding planes are separated to enable more flexible management of traffic through software programmable routers. Virtualization is usually considered to involve running several instances of servers in the same data centre, a practice which is quite well established in the cloud market.
However, both SDN and virtualization may refer to different network aspects or techniques, which depend on vendor strategy, network environment and legacy.
To summarize, telco SDN currently refers to the replacement of network components with software running on commoditized IT platforms. Several telecom network elements are particularly interesting for this scenario:
- Legacy and out of date equipment: Instead of having to maintain, support and upgrade equipment that is enabling legacy services, SDN can replace their functionality in software which runs on standard IT platforms. Network elements that are in this category include Broadband Remote Access Servers (BRAS) and PSTN network elements.
- Processing-hungry infrastructure: Software driven elements that can allocate processing capacity real-time are very relevant, so that overprovisioning can be minimized. Such elements include video or traffic optimization gateways or anything that requires a high processing load.