VoIP Power: BIG or BIGGER?

Sat, 06/30/2007 - 8:40pm
Traci Patterson, Web/News Editor

Operators have five-hour, eight-hour and 10-hour E-MTA batteries to choose from, and a headend to safeguard.

Subscribers have clearly come to regard cable VoIP (voice-over-IP) as a primary-line service, which compels cable operators to at least consider making sure the service stays on during a power outage, at least temporarily, and that means considering battery backup.

The question for operators used to be whether or not to include a battery. That’s been replaced by two questions: How much battery muscle is needed – a little, or a lot? And: Who’s going to pay for it?

Some cable operators are deploying batteries in their embedded multimedia terminal adapters (E-MTAs), as part of the voice or triple play subscription package, for every single one of their VoIP customers. Others deploy the batteries in just some of the E-MTAs they deploy, depending on the region or subscriber group.

And the batteries differ, as well. Some have an eight-hour standby and five-hour talk life; others have a four-hour, five-hour or 10-hour standby ability. (The times are an average estimate.)

RCN, for example, uses both eight-hour and five-hour standby batteries in its E-MTAs.

Comcast deploys eight-hour standby, five-hour talk batteries in every voice subscriber’s E-MTA. This is because its research, conducted before the launch of its VoIP service, found that when there is a power outage, it is usually for about a four-hour window, on average, says Cathy Avgiris, senior VP and general manager of Comcast Voice Services.

“The average minor power outage in the U.S. lasts less than five minutes,” says Haavard Sterri, executive director of marketing at SureWest Communications, so that eight-hour battery is almost always sufficient. SureWest has chosen eight-hour standby batteries to be placed in each E-MTA when the operator launches its VoIP service, hopefully before the end of the year.

There is no shortage of E-MTA manufacturers, and judging by their product portfolios, they’re all about giving their customers options when it comes to battery backup.

Arris and Motorola are considered the top dogs, but many others compete for market share, one being Scientific Atlanta (SA). SA’s DPC2203 two-line cable modem offers a battery-backup housing (with either one or two battery bays) on optional models. A 2200 mAh lithium-ion (Li-Ion) battery cartridge provides up to eight hours of standby. The DPC2434 two-line wireless home gateway houses a 2200 battery.

The company’s WebStar DPR2434 two-line wireless home gateway also houses a 2200 battery, but the WebStar DPX2203 two-line modem can be equipped with a factory-installed, rechargeable Li-Ion external battery pack to provide up to four, eight or 12 hours of standby operation. The WebStar DPX2203C two-line modem features an internal, cartridge-style Li-Ion battery with up to 6.4 hours of backup.

Arris’ E-MTA offerings include the Touchstone line of modems. The TM502G two-line modem and the TM504G four-line unit accept both five-hour and 10-hour standby Li-Ion backup, and the different-size batteries fit into the same enclosure. The TM501A is a two-line, non-battery-backed modem.

Motorola’s SBV5220 two-line E-MTA has two internal slots for eight-hour standby, five-hour talk batteries, but operators usually purchase it with just one battery. The SBV5121 contains no battery backup, but there is an optional external solution, the PB1000, if the operator decides to offer batteries in the future. That external solution also offers eight-hour standby, five-hour talk.

Arris’ TM502G
Arris’ TM502G

Jacob Igval, product manager at Motorola, says that the company’s E-MTAs have remote diagnostic and monitoring capabilities that can monitor the life of individual batteries. With an alarm at the operating system, operators can proactively reach out to consumers if something is wrong with a battery.

And not to be forgotten is Thomson. Its DHG535 two-line E-MTA provides battery backup, and so does its DWG855 two-line wireless cable modem. Both units contain two slots for eight-hour standby, five-hour talk batteries. Thomson’s DHG534 two-line unit does not provide battery backup. An interesting fact: Thomson has not deployed a single E-MTA with battery backup in Europe.

Self-install options for E-MTA batteries are a new and intriguing alternative, and some cable operators are looking to see if they can make it work, says Mark Howard, Arris Telewire Supply’s director of marketing. The theory is the same as with the data modem, but operators are hesitant about the difficulty of offering the option as of now.

The online availability of backup batteries is already up and running. If subscribers want to add an extra battery to their Arris E-MTA, for example, they can purchase one at The same goes for Motorola, where the batteries are available on the company’s Web site.

Of course, battery backup in the consumer premises equipment (CPE) means little if the network is down because of a power outage. John Hewitt, VP of sales at Alpha Technologies, likens cable operators’ networks to a car. In the first five years, the owner knows the car is going to start, he says, but after five to 10 years, it’s a different story.

The car owner knows at some point that the battery needs to be replaced and that he will need to purchase new brakes. And after 10 years of life, it’s unlikely that the car will become the family trip automobile of choice.

Since a lot of cable networks were rebuilt between 1999 and 2001, a large percentage of networks are just past the five-year mark. To offer a quality VoIP service, and other advanced services, there will be a heavy focus on preventative maintenance and keeping plants reliable in the next five to 10 years, Hewitt says.

Motorola’s SBV5220
Motorola’s SBV5220

“The networks are going to need more attention in order for them to be competitive with, or stay ahead of, the RBOCs’ networks,” he says. “It’s critical when you’re offering a primary-line telephone service.”

Most of the major operators are looking to increase runtime and install large generators on the headend side, Hewitt says. On high-end systems, it’s common to see redundant generators in case one fails during a power outage. “The cable operators are starting to look more and more like the telco companies,” Hewitt says.

Other operators are planning to upgrade their entire networks for adequate backup at the headend, Motorola’s Igval says.

And geography does play a role. “We’re seeing that there is definitely a disaster side to the design of cable plants today,” Hewitt says.

In areas with a higher probability of natural disasters (such as the South with hurricanes and the Midwest with ice storms, the two most disruptive disasters to cable networks), some networks will have longer runtimes. And an analysis is being conducted within the cable industry to determine the length and frequency of power outages by geographic location for this very reason.

As for right now, many products are available to strengthen operators’ headends. Alpha’s AlphaCell GXL and Gold-HP broadband batteries, which are high-performance silver alloy, increase runtime for VoIP networks. They provide 100 percent runtime capacity out-of-box, with no cycling required. The 180 GXL has the shortest typical runtime, with about 180 minutes, and the 215 Gold-HP has the longest typical runtime, with about 215 minutes.

AlphaGen portable generator
AlphaGen portable generator

The AlphaGen curbside generator system is designed for outside plant communication networks. Every system incorporates natural gas- or propane-powered engine generators, audible noise baffling, remote status-monitoring features and weather-resistant enclosures.

The AlphaGen Portable is a 3.0kW portable 36/48VDC generator system for emergency backup requiring no automatic transfer switch (ATS). It supports 3,000W of power and has an oversized fuel tank for up to 20 hours of runtime at 25 percent load, or 7.2 hours at 100 percent load.

The AlphaGen Portable Generator Trailer can store, transport and deploy 28 AlphaGen DCX3000 generators and accessories. The 16-foot-long trailer has a 10,000-pound capacity and is completely enclosed. The battery is always fully charged by a solar panel charger.

Alpha’s XM Series 2 with CableUPS uninterruptible power supply features modularity, increased output power and N+1 redundancy capability. It contains optional dual independent outputs, has flexible system control and advanced status monitoring, and it is AC- or DC-generator compatible.

And finally, the AlphaSource Galaxy 4000 is designed for data-center-grade power protection in critical environments. It features a fault-tolerant architecture to protect loads and the UPS unit during unintended faults.

SA Prisma ll XD
SA Prisma ll XD

And then there’s the cable modem termination system (CMTS) market. Motorola’s Broadband Services Router 64000 (BSR 64000) is a high-density, fully redundant, DOCSIS 2.0-compatible edge router. In the event that one power supply module fails, there is an uninterruptible transfer to a single supply.

Another headend helper comes from Arris – the C4 CMTS, a chassis that provides 99.999 percent system availability. The DOCSIS 2.0-based C4 – which is easily upgradeable to 3.0 – provides a design that sustains any system component failure without interruption of service.

BigBand Networks’ Cuda CMTS provides 99.999 percent system availability as well. The Cuda provides 1+1 supply redundancy, guaranteeing dedicated backup with no service interruption.

And last, but certainly not least, is SA’s Prisma II platform. The 19-inch-wide, modular chassis is designed to be used in a fully redundant configuration. And as with Motorola’s and Arris’ systems, there is an uninterruptible transfer to a single supply in the event that one power supply module fails.

Phone companies are compelled by statute to make sure that if the power goes out, phone service stays on. To that end, traditional telephony is line powered and backed by generators that phone companies can switch on in an emergency.

Thomson’s DHG535
Thomson’s DHG535

Cable companies have no such strictures, so their criteria are what will be sufficient for the least amount of money.

As might be expected, consumer groups and some governmental entities think cable VoIP should be just as reliable as traditional telephony.

Last September, a California bill was signed into law, and it requires the Public Utilities Commission to “consider the need for performance reliability standards,” and to develop and implement them, “for backup power systems installed on the property of residential and small commercial customers by a facilities-based provider of telephony services.”

Before Jan. 1, the commission is required to prepare and submit a report to the legislature regarding the benefits and drawbacks of such a regulation. The powering issue may not spread as quickly as the video franchise issue has in the state legislatures, but it’s definitely something that cable operators should watch out for as they continue to deploy more advanced telephony services.


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