CenturyLink cuts PSTN power consumption by 37 percent by 'grooming' Class 5 switches

CenturyLink (NYSE: CTL) has set a goal to reduce power consumption on its public switched telephone network by nearly 22,000 megawatt-hours a year, reducing greenhouse gas emissions as more customers migrate to VoIP and mobile voice services.

Although CenturyLink is growing its IP-based voice service, this project is focused on consolidating more than 400,000 legacy PSTN subscriber lines across 50 Class 5 voice switches. As a result, CenturyLink said it will reduce PSTN power consumption by 37 percent.

According to the telco, the reduction in power consumption is equivalent to supplying nearly 2,000 homes with electricity for a year while eliminating nearly 15,000 metric tons of greenhouse gases per year.

Pieter Poll, CenturyLink senior vice president of infrastructure planning, told FierceTelecom that this initiative will focus on Class 5 voice switches in major metros where energy usage is growing as more housing and business developments are built.  

"This isn't next-generation voice, but simply taking what you have on a switching platform that is empty to some extent depending on the region that you're in," Poll said. "When these switches were full, you occupied all of the ports and now, [with] folks that randomly left with the usual transition to wireless communications, we can realize a lot of savings in power consumption by re-grooming and packing switch modules, and turn down and remove the ones that are now empty."

These goals will be met by conducting a project in conjunction with Nokia (NYSE:NOK), which will supply its fixed network professional services under its PSTN Smart Transform solution.

Nokia says that the Smart Transform solution can help CenturyLink maintain its PSTN technology, protect voice revenues, and decrease the cost to serve existing customers.

Poll said that besides making its network more efficient, the project will enable it to become a more responsible corporate citizen in the markets where it operates today.  

"This is in the larger cities where the power needs are a lot more acute and it is really part of CenturyLink's citizenship in those cities to do its part to relieve power consumption -- 22,000 megawatt hours every year -- in savings," Poll said.

By using Nokia's PSTN Smart Transform migration service, processes and tools, CenturyLink will be able to consolidate customers into an energy efficient telephone switch configuration.

Working with Nokia, which purchased Alcatel-Lucent earlier this year, makes sense as the company is the manufacturer of the 5ESS Class 5 voice switch, a common platform used by large telcos such as CenturyLink. However, CenturyLink does have switches from other vendors such as Genband -- formerly Nortel -- and other platforms.

"What's unique here about Nokia is that they have great tolling and instrumentation, especially for the 5ESS switches, which are the ones that came from Alcatel-Lucent, Lucent and AT&T," Poll said. "They are extremely familiar with that platform and it's not exclusively 5ESS, but 5ESS is dominant because if you go back to Qwest/US West that was the big metro switch of choice."

While not a wholesale removal of all of its legacy switches, the project will enable CenturyLink to groom the switch modules. Depending on the size of a particular market, the switch modules on the 5ESS switches terminate 4,000 lines, groom to a set and shut down others.

"With promoting technology we can do more collapsing of central offices," Poll said. "I want to stress this is not a removal, but rather collapsing where I have 10 modules and I only need four and we can task those four to another central office even though their presence is still there."

Besides getting power from the local power company to run the Class 5 switches, telcos like CenturyLink also have to account for other issues such as cooling and battery backup.  

"It's not just the direct power plant, but the level of cooling, the amount of batteries you're going to need in the CO to provide backup," Poll said. "Power consumption is not just the power savings itself, but there's a multiplier for other things that use power to provide power in a reliable fashion, primarily cooling and backup."  

Ultimately, this project could also create an automated platform to transition legacy switches to IP-based platforms as demand dictates that need in certain markets.

"The secret sauce here is really the grooming and movement tools that allow you to do this," Poll said. "Telcos back in the day had whole teams that worried about switch cutovers and we need an automated capability to do this. It simplifies the frame structure so when we think about next generation we have a simplified structure in how to do this."

CenturyLink may be the latest to take on a grooming project of its PSTN infrastructure to reduce energy costs, but it is hardly alone.

A Genband study revealed that although service providers continue to see their PSTN revenues decline, the cost to power legacy COs continues to rise. Today, $63 billion is spent on powering these COs.

After Hurricane Sandy, Verizon (NYSE: VZ) had to take out all of its damaged TDM-based equipment in New York, convert and re-create it to IP, for example. This gave Verizon the opportunity to reduce its network footprint and monetize the buildings with other real estate uses.

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