DENVER -- Cable Next-Gen Broadband Strategies -- Some MSOs are considering a budding Society of Cable Telecommunications Engineers (SCTE) standard called RF-over-Glass (RFoG) to serve limited residential "greenfields" and local businesses opportunities, but it's becoming apparent that RFoG is viewed as stepping stone toward more advanced PON-based network schemes.

RFoG enables MSOs to pull fiber to the home or business while preserving the MSO's headend and backoffice systems. Although it doesn't offer much in the way of additional capacity or speed, RFoG does handle the operator's legacy voice, data, and video services, and supports existing Docsis cable modems, embedded multimedia terminal adapters (E-MTAs), and digital set-tops. (See RFOG Comes Rolling In , and Lifting the Fog on RFOG, and SCTE Moves on RFOG.)

Trials and deployments of RFoG are rolling in. Heavy Reading estimates that North American MSOs will pass no more than 50,000 to 100,000 homes and businesses with the technology by the end of this year.

Even if RFoG deployments begin to ramp up in 2010, it's becoming evident that MSOs will add in PON extensions to beef up the bandwidth.

RFoG "is certainly not the end-game," said Jeff Stribling, the VP of marketing and customer service at Salira Systems Inc. "There will be continuing bandwidth demands on the downstream and upstream directions. [Cable] needs a solution that scales for bandwidth. That's where PON has the advantage to take the step beyond what RFoG can do."

Although MSOs could put in RFoG or PON-based extensions to serve pockets of greenfields, don't expect them to rip out existing hybrid fiber/coax (HFC) in favor of fiber-only platforms until it's absolutely necessary. And don't expect MSOs to rapidly upgrade existing RFoG installations with PON.

"Cable operators hate to throw anything away," observed Bill Dawson, the VP of business development and product strategy, access products, at Arris Group Inc. (Nasdaq: ARRS). "Whatever RFoG solves will be used for as long as it does the job."

Cox Communications Inc. , an MSO that issued a fiber-centric RFI (request for information) last year, has installed some GPON to serve commercial customers and is currently evaluating RFoG as another way to serve businesses. As one result of that RFI, Cox has selected Calix Inc. (NYSE: CALX) as a GPON vendor. (See Cox Flirts With Fiber .)

But whatever the future holds, any architecture for business services will support a video component. "We consider video a key part to that [business] service offer," said Dan Estes, Cox's executive director of business operations and engineering.

But, on the residential side, Cox believes HFC will continue to be adequate for years to come. "There is no crisis," Estes said.

Rather than pulling fiber all the way to the residential customers, Cox is future-proofing its network by reducing node sizes and the number of active amplifiers hanging off those nodes, and expanding spectrum to 1 GHz. (See Cox Makes 1 GHz Moves .) However, Cox is looking into residential scenarios in which it might target FTTP to serve an individual "super user," so long as that customer is willing to pay the requisite premium.

Buckeye CableSystem , an MSO based in Toledo, Ohio, has employed PON for business services for several years, most recently with GPON. However, it is already starting to think about when it might make sense to switch its entire residential services platform to an all-IP environment. Today, Buckeye uses IP for voice and data, and it may only be a matter of time before it goes with IPTV, hinting at that strategy last week when it announced a deployment of switched digital video. (See Buckeye Picks BigBand for SDV .)

"The more effective IP [becomes] the more difficult it will be to sustain a QAM-based, tuner-based [video] solution," said Joe Jensen, Buckeye's EVP and CTO.

Cox, however, does not see a full IPTV migration anywhere in its near-term future. "The investment in the headends, set-tops, and the magnitude of solving that problem is more than anyone can bear," Estes said.

GPON or EPON?
But if PON is the answer for some limited cases today and could be the long-term answer, will MSOs use GPON, as Cox and Buckeye are today, or will they go with EPON, a technology that some view as more compatible with cable's existing HFC networks? (See Time Warner Cable's Fiber-licious RFI .)

Arris, Dawson says, believes EPON is more "friendly to [cable's] core transport." As such, Arris's upcoming RFoG product will have EPON capabilities, he noted.

Floyd Wagoner, director of global marketing for access networks solutions at Motorola Inc. (NYSE: MOT), isn't so sure. He say's EPON usage is relatively "isolated" to Korea, Japan, and Hong Kong, while GPON enjoys more global adoption. He believes China, where MSOs are considering PON upgrades for their old one-way cable plant, could be the difference-maker.

"It will come down to China," he said. "If China goes GPON, the world goes GPON." But Motorola isn't betting all its chips on GPON just yet. Instead, it's developing a portfolio that includes RFoG with options for GPON and EPON. (See Moto, Alloptic Tag-Team on RFoG .)

Salira also isn't willing to stake everything on one technology. "Who will win? Maybe both," Stribling said. "We're trying to provide a portfolio that addresses the needs of all the MSOs."

For Cox, the decision has been a simple one so far as it targets PON at some commercial service opportunities. It went with GPON over other options because it offered more bandwidth at the time Cox was pondering installations, Estes said.

— Jeff Baumgartner, Site Editor, Cable Digital News