You know all those commercials Verizon is running with a young boy talking about “30db hot” and in which, in open-mouth wonderment, he seems to be awash in light? Well, fudgedaboutit, at least when it comes to multiple HD video on demand streams and high-speed Internet.

Not many people realize that FiOS uses a hybrid system for video. It uses both QAM (what we think of as “normal” cable) for much of its programming. But for VOD, it’s IPTV. IPTV data streams are delivered via the Actiontec routers that Verizon requires customers to use because these routers have a network interface module, or NIM, that bridges IEEE 802.3 Ethernet as we know it to the set-top boxes. The set-top boxes are connected by coax cable, of course, and a standard called MoCA (multimedia over COAX) enables them to receive IPTV. It might surprise people to know that FiOS set-top boxes get an IP address from the router just like computers do. To try to make sure that the VOD video streams do not detract from subscribers’ Internet connections, the router implements QOS for the the IPTV video streams.

Complex? You bet. And it all worked great until VZ started offering HDTV VOD.

Tonight, for the first time, I had two HDTV streams going and it killed my Internet connection. I called VZ and the first thing the guy tried to make me do was factory-reset the router. When I objected, he told me that “hundreds of customers watch multiple HTDV VOD streams while getting full bandwidth from Internet connections.” Because I insisted, he agreed to consult with a video expert.

A few minutes later, he came back on the line and admitted that FiOS can’t support more than one simultaneous HDTV video on demand stream. He didn’t blame the router. Astonishingly, he blamed the ATM switches in the central office. (ATM is old, old, old, and I can’t believe VZ implemented it in FiOS…they can’t seem to help themselves. Billions to build a new network, but they’re still using protocols from the 70s in it.)

Bottom line: when you get FiOS you get fiber, all right. But you don’t get the ability to really use its capacity. In fact, it’s easy to overwhelm it.