Note to proponents of any particular home networking technology: Don't get too comfortable, and prepare for battle. Handicapping the race between various home networking technologies vis-à-vis the IPTV market has become increasingly difficult, as vendors and carriers throw support behind different camps and switch alliances faster than reality show combatants.

Last week, the Multimedia over Coax Alliance (MOCA) picked up two significant endorsements when Siemens' customer premises equipment group and Alcatel joined the coalition. Because Alcatel holds the primary supply contract for AT&T's rollout of its U-verse video service, Alcatel's endorsement further legitimizes a technology that already has plenty of support in the cable industry. It also has backing from Verizon.

For Alcatel, it was a matter of making sure it has all its bets covered, said Steve Kemp, senior director of product marketing for the vendor's access division. “It's like a lot of standards: you'll have lots to choose from,” he said.

MOCA, however, appears to be losing support from an early proponent: 2Wire. The vendor, which recently sold a significant equity stake to Alcatel and AT&T, released the latest version of its residential gateway with support for the Home Phoneline Networking Alliance (HPNA) version 3, but not MOCA. HPNA uses in-home twisted pair, while MOCA — as its name implies — uses existing coax to ship data and video around a house.

“We've found that MOCA still isn't an open standard that you can write silicon to,” said Jaime Fink, director of product marketing for 2Wire. “It also was surrounded by difficult business practices.”

Carriers are keeping all options open. “The engineers have two choices, and that's a great place to be,” said Jeff Weber, vice president of product and strategy for AT&T, which recently joined HPNA but is testing both technologies.

Don Granger, president of BellSouth Entertainment, said the carrier is field testing IPTV in 250 homes in Atlanta using HPNA, MOCA and even some Home Plug Powerline Alliance equipment, which uses in-home electrical lines to transmit data and video.

“What we're looking at is what's the most cost-effective and least disruptive to the customer,” he said. “You have to look at the complexity of each individual household.”