The Telco Challenge
The current contribution of ICT industry to the global CO2 emission is at 2% and it expected to double by 2020. In many parts of the developing world, Diesels generators power the telecom networks. The cost of running a BTS for 8 hours on Diesel accounts to be approximately 64% of the TCO of the cell site.
Look at the telecom Market in India. The mobile service tariffs in India are lowest in the world, whereas only 33% of the telecom towers get Grid power. The cost of running a tower on diesel is double than that of running it on Grid power. In developing country like India, though the volumes are high, the margins are low. The OPEX of running cell sites on Diesel generators is undue pressure of the margins. This is a real challenge for Telcos.
To make the matters worse, the huge carbon footprint of ICT sector has caught the eye of regulatory bodies. There is a lot of pressure on Telcos to go green. The cost of running a cell site on Renewable energy like solar power is 3x the cost of Grid power. So the solar energy will take some more time before it becomes key energy source for Telcos.
The Telecom Regulatory body of India (TRAI) has mandated a new policy to make Telcos green. This policy is estimated to cost a whopping 660 Billion. But there is no clarity on who will bear the cost :(
What are the reasons for power wastage?
Every electronic device needs power to run and there is nothing much that can be done about it. If we look at the relationship between power consumed and device utilization, there is no direct proportional relationship.
A typical device running at 5-15% of utilization consumes 60-90% of rated power. There is clearly a lot of power wastage resulting here.
If the Telcos could reduce this gap between power consumed and device utilization, the power bills and the carbon emission can be considerably reduced.
How SDN can help?
If we correlate the key aim of SDN of “separating control plane from the date plane” with this power management problem, it looks like SDN is the technology that will help Telcos in managing the energy demands and their carbon footprint. Let’s see how…
The power management of a device is taken care by the firmware of the device and the firmware is not changed often. Thus a device, once added to a network, the power consumption of the device is nearly constant throughout its life in the network.
- Decouple power management from the device
What if we separate the software part that managed the power of the device from the device the way we are doing it in SDN by having a separate control Plane?
Now the control has the routing algorithm as well as the power management algorithm tightly coupled. If the control plane is diverting traffic that amounts to 5% utilization of the device, the device consumes power proportionally. If the device is serving 80% of the traffic, it has all the rights to consume power proportionally higher than the device that serving only 5% of the traffic.
- Control Standby mode
Many a time, during the peak hour, the network devices are hardly serving any traffic. Why not put some devices into standby mode? The control plane of SDN computes the maximum number of devices required based on the forecasted traffic and the most power efficient devices that can serve the need. All the other devices are then put into standby mode.