MOVING ON OUT

The push toward next-generation networks is driving the use of smaller plant solutions that serve both fiber in the loop and the CO, pushing the need to distribute power to better serve subscribers. As networks become more data-intensive, carriers will start swapping out centralized power systems in favor of distributed architectures.

Say goodbye to large centralized power plants? That's unlikely in these tough economic times. But as the telecom industry moves toward next-generation networks, the need for large, centralized power plants will diminish.

Small, distributed plants that put power close to the subscriber have been in evidence for quite a while — more than 10 years, according to Skyline Marketing Group. But it's becoming more prevalent as carriers migrate their networks from circuit-switched to packet networks and from copper to fiber optics.

Next-gen networks demand greater amounts of power in smaller, denser arrangements that not only serve COs but also outside plants. As telecom networks become more data-intensive, those power systems are evolving to meet the need for greater power.

There are engineers that favor centralized power arrangements vs. distributed power arrangements and vice versa. Both have their advantages, but there are also trade-offs.

“It's more a matter of preference and circumstances,” said Mike Buskmiller, senior product manager for Tyco Electronics Power Systems. “We have some customers who serve financial institutions that are extremely concerned about reliability and uptime. [One] customer has a distributed architecture in three points in a room.”

Though a centralized system is easier to maintain and operate because it's all in one place, it provides a single point of failure. A distributed power arrangement eliminates this single point of failure and reduces downtime if power failure were to occur. “Zero downtime has become a crucial element for most enterprises,” said Farah Saeed, industry analyst for Frost & Sullivan.

And deciding to use a distributed architecture is also more economical. “We've seen a shift to distributed [power] where upfront costs are lower,” said Roger Stonecipher, senior product manager for Tyco Electronics Power Systems. “You just pop in a new bay as your network grows.”

While eliminating failures and reducing costs seem good enough reasons to move to distributed power, the telecom industry's use of more bandwidth-intensive applications such as DSL, digital loop carriers and fiber optics also requires that power be placed closer to the user. In addition, network access equipment and data management equipment is moving closer to the end user.

This distributed architecture is a more efficient way of managing traffic. As carriers make the move to an IP-based model and more data gets put on those lines, a distributed architecture allows for optimal switching so that information can be more easily routed.

“It's really based on how networks are evolving,” said Bill Felix, senior vice president for worldwide network technology, engineering and plant for Qwest Communications. “It's related to DSL and lots of these other newer services [being rolled] out that have the capability to do what is done in those large [central] offices today. Hence, you will end up with a distributed architecture over time in that it's much more efficient to provide switching and intelligence at the first point you can.”

Barry Papermaster, vice president of sales for Emerson Energy Systems, agreed. “You literally have hundreds of boxes distributed throughout the building,” he said. “Now the processing power has migrated out from one big box, and very often it's migrating out toward where the end users are.”

And power is migrating, too. Because distributed power is getting placed closer to the end user, if there is a failure, there's less impact on the carrier's network. There are also economies of scale when deploying distributed power. “You can come up with a cookie-cutter design and deploy it as needed and then time-phase capital expenditures with the growth of the network,” said Steve Vechy, director of marketing for Enersys.

Bandwidth-hungry businesses and residential users searching for more data, voice and video services are pushing for more distributed power architectures because these services need more power closer to the end user. “The more sophisticated the network, the higher the priority given the powering portion of the network because of the direct link between the power system and the overall network reliability,” said Eric Wentz, vice president of marketing for Alpha Technologies.

Today, however, the majority of carriers using centralized power arrangements are not likely to swap out an entire system based on cost factors alone. “Really, it's an economics decision,” said Dan Baeza, general manager for BellSouth. “To set up distributed battery locations for the purpose of providing power would be somewhat costly. It would require monitoring. It would require a commercial feed to charge the batteries, and you can do all that in the CO fairly readily.”

To date, most carriers have a centralized power system, with the exception of remote terminals in the CO that use their own batteries. What is driving distributed power is the building of next-generation architectures where, in the long term, the network will be a fiber-based, all-packet and all-optical network. For example, BellSouth is building such a next-generation architecture.

But building such a network such as this takes time, and the current recession also is affecting the pace at which carriers are evolving their network architectures. “Building a network such as this is a journey rather than a destination,” Baeza said. “A number of factors have to be balanced, [including] the speed it can be constructed, the economic value and the economic value statement that we can make to our customers.”

Right now carriers are likely to swap out and replace battery and power systems as needed. According to John Celentano, president of Skyline Marketing Group, even though there's been a lot of new power installations during the past couple of years, carriers are more likely to tweak and update what they have rather than completely replace whole battery power units (see sidebar, below). “Unless the conditions of the batteries are such that they don't have any choice [but to replace them],” Celentano said. “For the time being, it's safe to say that a lot of carriers are making do with what they have, and unless they're forced to replace the batteries, they'll probably let it ride for a period of time.”

But the cable industry seems to be stepping up where telecom has lagged. “Telecom has really slowed down,” said Roger Ianetta, senior product manager of the DC networking group for American Power Conversion. “People are vacillating between going on interim solutions or next-generations solutions, which has allowed the cable companies to step in.”

In the end, the decision for a service provider to migrate its network from a centralized power architecture to a more distributed power architecture depends on the specifics of a particular carrier. “There are no hard and fast rules,” Wentz said. “It ends up being a network designer's responsibility to balance the needs and objectives of the network with the overall parameters associated with that given network or service area.”

SMALLER PLANTS, SMALLER BATTERIES

Though a distributed power architecture has been chosen for a network, the work's not over. There is also the decision of what type of battery to use because power requirements in distributed setups are higher in terms of thermal range, power densities, remote monitoring and proactive battery management.

According to Roger Ianetta, senior product manager of the DC networking group for American Power Conversion, the use of distributed power will help alleviate excessive heat issues associated with greater power needs. “You need thermal control, and you need to thermally manage those [outside plant] enclosures,” he said.

So the move from a large centralized power plant to smaller plants out in the field has altered the types and sizes of batteries used in telecom. Because batteries within the CO must carry large loads for longer periods of time if there is a utility power outage, flooded batteries are the batteries of choice.

“The power requirements have changed. We're [still] talking UPSs and 48 V systems,” said Charlie Potter, specialist in real estate operations for Verizon Communications. “But switches are smaller, and current requirements are much less. And since floor loading [is changing, you] can use smaller cables.” Verizon is moving toward a distributed power arrangement in its new facilities, Potter said.

Outside plants, generally located along a sidewalk in a neighborhood, require smaller, more densely packed batteries that resemble car batteries, which are placed in cabinets. “We responded by reconfiguring [batteries] to fit into as small a space as possible and to be easily integrated into an existing or some other existing systems,” said Keith Jungermann, Panasonic MSE business unit manager.

Sealed batteries, on the other hand, require less maintenance, are more environmentally resistant and are designed to work out in the field.

Because there has been a market demand for wireless networks and more telecom equipment, battery configurations have improved. These batteries are designed to survive longer, perform well under extreme conditions and reduce future costs.

Flooded batteries, for example, have longer durability but are harder to manage in outside plants — thus the shift to valve regulated lead acid (VRLA) batteries. But VLRA batteries are estimated to survive only five to seven years.

While there has been some talk of replacing batteries altogether, no one is close to doing so. “Batteries end up providing and filling a critical role with regards to providing backup power in the network, but batteries have limits,” Wentz said. “And some networks end up requiring additional backup power or more power than what a battery-only power system can end up providing.”
— Amalia D. Parthenios