At the Optical Fiber Communications conference this week, Verizon Communications named the first two locations it will commercially deploy gigabit passive optical networks (GPON)--a higher-speed version of its current fiber-to-the-premises (FTTP) technology. Mark Wegleitner, the carrier’s chief technology officer and senior vice president of technology and network planning, spoke with Telephony’s Ed Gubbins about Verizon’s future migrations to GPON, IPTV and in-home customer premises devices.

On GPON and IPTV: We’ll continue using RF overlay to deliver video on GPON. It’s been a terrific service delivery package for us. It puts the broadcast channels out there. It’s a very mature technology, stabilized and available and relatively low cost. So [we’ll] stay the course, initially. [In a keynote speech at OFC,] I made the connection between IPTV and GPON because, by going up to 2.4 Gb/s [downstream] and 1.2 Gb/s [upstream], we have more than enough bandwidth to offer IPTV, including broadcast to all 32 customers. We can do this on BPON at 622 Mb/s, but it’s possible we’ll run into some bandwidth constraints; we may have to change the split from 32 to 16 to accommodate that. So we can do IPTV on BPON, but we may have to make some accommodations. If we do it on GPON, we should be clear from the get-go.

On launching IPTV: Market behavior will drive us to IPTV. It could be that it’ll be 1,000 channels, in which case maybe the time has come to go to switched digital IPTV instead of linear broadcast delivery. It could be that the multiple camera angles with sports events takes off, and that’s better served through an IPTV infrastructure, even though a certain amount of that could be done through what we call a hybrid infrastructure today. It might be that the quality of time-shifted programming and use of the [digital video recorder (DVR)]—maybe the network DVR will actually come about, and we won’t have a need for real-time broadcast delivery the way we do today. All these factors will impact the market side of that decision. The technology side of that decision is just: When can I build a scalable, switched digital IPTV system that can serve millions of subscribers cost-effectively? We’ll be monitoring that as well.

On moving [optical network terminals (ONTs)] inside the home: We've got two devices we’re installing in the home right now: The ONT on the side and the broadband home router (BHR) in the home, plus the set-top box. What if you could put those [first] two together? If you bring the BHR out to the ONT, it’s very difficult to get wireless coverage for the additional PCs in the house. They could be in the basement, or you don’t get a good shot in from the other side of the house. We’ve had mixed success, let me put it that way. There’s a possibility something like 802.11n might come along and help us in that regard. We look at that as an opportunity. We just put it on the radar right now; it’s not necessarily something we’re very aggressively pursuing. Similarly, we could take the ONT and move it to the BHR, which is sitting on the desk usually next to a PC, where it’s connected to the first PC through Cat 5 wire. Yeah, there are some powering implications, but they’re not particularly troublesome. We can power laptops; the cable industry is powering indoor NIDs today for voice services. The battery and power can still plug into the wall outlet and, in fact, there’s probably easier access to a wall outlet from that desktop than there is where we’re putting ONTs today. But it does mean you've got to bring the fiber in, and you've got to find a way to route it--either through the walls or around the molding or something like that--to a combined ONT/BHR inside the house. It’s just something we want to make sure we fully explore.

On multivendor OLT/ONT interoperability: ONT interoperability is a requirement we've had for some time. It isn’t one we push really hard. First, we don’t want to deprive suppliers of the economics of providing both ends of the PON system. Second, it’s much easier to buy both pieces of equipment from the same supplier because you're pretty much guaranteed it will work. It’s not just a question of getting communications channels to talk to each other; it’s also the maintenance of the two devices. There’s a coupling of the OLT and the ONT from a maintenance perspective. At a minimum, we’d expect the number and variety of ONTs we’ll ultimately need--to serve small businesses, [multi-dwelling units (MDUs)] and [multi-tenant units (MTUs)]--will be so great that no OLT manufacturer will want to do them all. Therefore this concept of interoperability will probably come into play sooner or later. There are standards--G.983 for BPON, G.984 for GPON--that define the way to make an OLT work with an ONT. While it isn’t going to be a slam dunk, it isn’t going to be that hard to do, in my estimation.

On multimedia over coaxial cable (MoCA) technology: MoCA is the approach we’re going to use for the time being. It’s got a lot of legs to it. We want to make sure we can get 100 Mb/s around the house. It won’t be the only approach we use or necessarily our main approach forever because there are other technologies potentially out there that could be used as well. We’ve always kept an eye on HPNA 3, which might have a place in our network one day. We think [ultrawideband technology] is particularly promising in the near future but not right now. We think ultrawideband could play a fairly significant role if it continues to develop the way we see it developing thus far. Though MoCA is our choice right now, I think that’s still worthy of a lot of investigation.

On GPON and high-definition TV (HDTV): RF overlay between BPON and GPON is virtually identical. You’ve got HDTV in one and the other in about the same quantity, depending on how we want to allocate bandwidth in that 860 MHz. When it comes to interactive HDTV, or HD [video on demand], increased [bandwidth] will play a role in being able to deliver that easier. But we can even deliver that on BPON. It’s just that more downstream [bandwidth] makes it easier.

On WDM-PON: We’re not counting on it in our network for another 3 to 5 years. There has been some deployment worldwide that we continue to monitor. But we think GPON's got a pretty solid interval for deployment here. It’s a capable platform; we’ll continue to use it. When and if WDM-PON and 10-Gb/s PON come along, they’ll go through the same evaluation process we used on GPON.