Verizon is preparing to introduce an advanced fiber-to-the-premises (FTTP) architecture that will produce faster Internet services, and set the table for future IP-based video services, including more bandwidth-intensive high-definition television (HDTV) fare and expanded video-on-demand (VOD) capabilities.

Verizon's present FTTP deployments are based on BPON, an ATM-centric architecture that produces shared speeds of 622 Mbps down/155 Mbps up. BPON capacity limits, coupled with the relative nascence of IPTV technology, led Verizon to initially use a cable-like RF overlay to distribute most of the programming for its FiOS TV service.

With the more advanced GPON architecture, Verizon will be able to provide shared downlinks of 2.4 Gbps.

Although GPON provides higher capacity, it can leverage OLTs (optical line terminals) that serve 64 customers. BPONs use 32, meaning the bandwidth is split 32 ways. A GPON can split the bandwidth 32 or 64 ways. On a dedicated basis using the 64-split model, that means one home can get 37.5 Mbps on average, but likely much more than that (100 Mbps-plus) on a shared bandwidth basis.

The telco has already selected three GPON vendors: Alcatel, Motorola Inc., and Tellabs. Verizon said it will deploy Alcatel GPON gear first.

"In addition to the ability to boost our broadband Internet speeds on fiber, this new technology will enhance the video-on-demand capabilities of our existing FiOS TV product on fiber, and sets the stage for an all-IP TV offering in the future," said Paul Lacouture, Verizon's EVP for network and technology, in a statement.

Verizon also hopes a GPON strategy will give it more bang for the buck. According to ballpark estimates from industry experts, the per-customer costs for the BPON central office is about $330, and the network terminal unit, which is affixed to customer homes, is about $260. In volume, GPON costs will be similar, though Verizon believes the move to GPON will reduce costs linked to the electronics portion of the FTTP platform by about 25 percent.

In February, Verizon Vice Chairman & President Lawrence T. Babbio Jr. said targeted per-home or per-business costs for BPON-based FTTP in 2006 are $890. That figure, which includes aerial and underground FTTP, averaged $1,400 at the start of 2005, he said.

Verizon has not said specifically when or where it will begin to deploy GPON, though it should start sometime before the end of the year, a company spokesman said.

Verizon, which expects to have close to 6 million homes passed this year with FTTP, also doesn't expect to change-out or retro-fit its existing BPON systems with GPON technology for some time. BPON, the spokesman said, will provide enough capacity for video and broadband services for the "foreseeable future," despite the additional headroom supplied by GPON.

Moving forward, Verizon said it plans to pass an additional 3 million homes with FTTP each year for the next "several years."

So, why didn't Verizon just go with the faster GPON platform from the beginning? That technology was only "marginally available" and GPON standards were just being set in stone back when Verizon launched the FiOS effort, according to Clifford Holliday, the president of B&C Consulting Services, and an analyst and writer for Information Gatekeepers. Additionally, BPON fit nicely with Verizon's existing ATM backbone, which reduced conversion efforts significantly right off the bat, he noted.

Still, if Verizon decides to retro-fit its BPON systems, "they're not in a bad situation," Holliday said, noting that they won't have to change-out the fiber infrastructure, but will have to replace the terminals on sides of homes and the unit in the central office.

"They (those components) are all accessible, so [Verizon] doesn't have to worry about the customer being home. They'll be able to upgrade where they need to pretty readily."

In addition to Verizon, an eventual move to GPON could be in the cards for other telcos due to the bandwidth demands of increasingly popular services such as HDTV.
"The fact is, [GPON] is the only thing they can really do to provide the bandwidth that they'll need," especially in the 2006 to 2010 timeframe, he said.

BPON and copper-based VDSL technologies, which AT&T is using for its "U-verse" IPTV service, "just won't cut it," Holliday said. "Our forecast is that ultimately they'll all be going to GPONs."

Companies that have invested in VDSL technologies would likely disagree with that assessment. Ikanos Communications, for example, just released an "IPTV optimized" VDSL2 chipset designed to produce symmetrical speeds of 100 Mbps.

But HDTV, particularly multi-tuner HD-DVRs, will have a voracious appetite for bandwidth, Holliday explained. Without advanced compression, watching one HD channel while recording another will absorb about 40 Mbps. And that's just one television. The average home has 3.5 TVs, though most are of the standard definition variety.

"You're going to see a requirement for 35 Mbps to 45 Mbps to the home real quickly in terms of digital provisioning," with current compression schemes, Holliday said, adding that the figure does not even factor in what's required for high-speed Internet services. Bandwidth for IP voice, meanwhile, is simple overhead, and barely registers on the overall bandwidth requirement graph.

More detail on those bandwidth estimates will be revealed in a forthcoming report from Information Gatekeepers that attempts to answer the simple, but important question: "How much bandwidth is enough in the access network?"