By Dimitris Mavrakis

It feels like 2006 once again: vendors are creating fanciful and colourful presentations about SDN and operators are discussing about the need to move from silos to horizontal platforms and networks. In a way, almost the same story was told six 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 commoditised 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. Virtualisation 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 virtualisation may refer to different network aspects or techniques, which depend on vendor strategy, network environment and legacy.

To summarise, telco SDN currently refers to the replacement of network components with software running on commoditised IT platforms. Several telecom network elements are particularly interesting for this scenario:

Enter NFV

In order to address the cacophony of different definitions for telco SDN, operators have setup the Network Functions Virtualization (NFV) forum which is described by the following:

Key operators, including AT&T, Telefonica, Deutsche Telecom, Vodafone, France Telecom and Verizon Wireless and several vendors including Alcatel Lucent, Cisco, Huawei, IBM, Juniper Networks and NSN are founders of the NFV forum. An interesting departure from the standard membership model of telecom bodies is that IT vendors have joined, indicating that there is considerable potential in the telecoms environment.

The member list of the NFV forum can be found here and the white paper outlining the mission of the NFV here.

Why now?

SDN and NFV arrive at an appropriate and interesting time for carrier networks. The following reasons are key factors for the increasing interest in telco SDN:

On the other hand, telco SDN currently has some serious challenges to overcome:

Is telco SDN the new IMS?

Telco SDN essentially promises the same thing that IMS promised six years ago: horizontalisation of the network without clear revenue opportunities. However, telco SDN (and the NFV) have serious advantages over IMS: SDN is already being implemented in the IT domain and operators and vendors will have learned from their involvement in IMS. Also, SDN is attempting to enter the market by converting practices and technologies from the IT domain so that they can be applied in the telecoms environment. Contrary to this, IMS was a completely new – and very optimistic – concept.

The future is brighter for telco SDN. Although vendors may be currently marketing it similarly to IMS, operators will surely make sure that outcomes of the NFV address their key concerns – and tone down vendor hype.