Verizon FiOS TV: Network Architecture

Verizon uses a network design that looks similar to traditional cable but includes such telco-like touches as duplicate headends and Sonet rings. In addition, the carrier is using a combination of traditional radio frequency (RF) carriage as IP. At the core of the network, the company has set up two super headends (SHEs), one in Temple Terrace, Fla., and another in Bloomington, Ill. The SHEs will both take in the same national content from an array of traditional cable networks. In the event of failure, one SHE will be able to provide content to all sites. From the SHEs, video is sent over Verizon's Sonet to hub offices where local off-air networks as well as required public, educational and government channels are injected. For example in the case of the Keller launch, content will come from a hub office in Carrollton, Texas.

Video-on-demand (VOD) will follow a similar path with some being stored at the hub office on local servers. However, from the hub office, linear programming from the cable networks will be sent to local central offices and over the FTTP network using RF technology while all VOD content and the interactive program guide will come into the home over IP. Unlike SBC Communications and BellSouth, which have committed to launching all-IP video networks, Verizon believes mixing formats is more appropriate given the state of the technology.Cable TV providers typically have a 860-MHz channel to serve each house, and have to divvy up that capacity if they want to add services such as video on demand, Internet access and VoIP.

Verizon delivers three wavelengths of light to each house: a 860-MHz video channel; a 622Mbps channel for voice, data and video on demand; and a 155Mbps return channel for voice and data (the 622M and 155Mbps channels are shared by up to 32 households).Using different channels means Verizon can more readily accommodate changing demands without sacrificing one option to offer another.Unlike cable operators it doesn't use up digital channel capacity to also offer voice, VOD and information services, which consume 10 times the bandwidth of video channels. Verizon is offerring analog because there is a group of people who don't want to have a set-top on every TV set. They want that TV set in the kitchen or the basement to be able to get basic cable channels on a cable-ready TV.

Verizon does surrender some of its 860 MHz of RF capacity to provide 24 channels of analog, but provides all other service — voice over IP, information services and VOD — via IP streams that don't consume any channel capacity. That's a distinct advantage over cable companies. Companies such as AT&T, which is offerring IPTV over a fiber-to-the-node network, can't deliver multiple HD channels as Verizon will be able to over its FiOS FTTP network. By using IP streams within the home network, Verizon will soon be able to offer its TV customers multi-room DVR capability that can record two HD channels simultaneously, while delivering two others for immediate viewing.

Foreseeing the future, Verizon, AT&T and BellSouth have participated jointly in a Gigabit passive optical network (GPON) request for proposal (RFP). GPON will offer 10 times as much capacity as compared to current capacity. The current ATM-based passive optical network (PON) can deliver up to 100 MB/s of capacity. Considering the future interactive applications GPON will be boon for IPTV deployment. Verizon is using the MOCA — multimedia over coax cable — specification for routing signals in the home and will integrate MOCA into set-top boxes by the second quarter 2006. (MOCA certainly deserves one post on this enigmatic blog :)) Isn't it)While Verizon's network is costing about five times more to build than AT&T's, it will offer almost limitless bandwidth. AT&T's network, on the other hand will initially offer about 15Mbps to 20Mbps. And even though advances in DSL technology will allow it to push up these speeds, it will always be more limited than Verizon's fiber network.

Because of this limitless bandwidth, Verizon is using MPEG-2 encoding (not MPEG-4 AVC or Windows Media, which require half the bandwidth or less); allowing it to implement TV with today’s lower-cost MPEG-2 gear. The potential is there to have two different multi-stream PVR-enabled set-top devices in separate rooms, to simultaneously watch one high-definition program while recording another--a total of four program streams, even if one or more of them were in high-definition. Inside the home, Verizon will be using three different Motorola set-top boxes — one standard definition, one that includes a high-definition decoder and one with an integrated digital video recorder. The company will use existing in-home coax to transmit between the optical network units on the side of the home and TVs for both linear and VOD programming. Video entering as an IP stream will be sent to Motorola's set-tops using Multimedia Over Coax (MOCA) technology. Those set-tops, based on the vendor's DCT cable line, also are something of a hybrid because they can receive QAM video but also IP because of the integrated MOCA technology.

Set Top Box (STB)

The Motorola QIP family of set-tops features both traditional RF video, using quadrature amplication modulation (QAM) and IP video, and incorporates the multimedia over cable (MoCA) specification for sharing content within the home over existing coaxial cable. The dual QAM-IP capabilities are an important part of Verizon's FiOS offering, since the company is using RF to deliver basic cable programming and IPTV for its video-on-demand and other advanced services.

Finally: Moolah

The way Verizon sees it, the market for pay TV and online music and gaming adds up to $120 billion per year, or about $29 billion worth of opportunity within the geographic footprint the company serves.