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AT&T Finally Deploying Bonded VDSL
Though the goal's to extend reach, not speeds
by Karl Bode 03:23PM Thursday Jul 15 2010
AT&T's decision to run FTTN instead of FTTH has remained a sticking point, with AT&T's top U-Verse speed (after video) sitting at 24Mbps downstream and 3 Mbps upstream for customers within range. While that speed is (at least downstream) nothing to laugh at, it's quickly being overshadowed by Comcast deployment of 50Mbps DOCSIS 3.0, which is now available in more than 80% of Comcast markets (with 100 Mbps to come).

Pair bonded VDSL was supposed to be AT&T's retort, with AT&T enlisting a second copper pair to each house to increase U-Verse's maximum delivery range and speeds. But after telling us we'd see a 2007 launch, deployment was delayed due to modem chipset issues. More recently we've seen some of our users told the technology was almost ready, and now AT&T tells us that deployment is finally here.

According to AT&T, they're starting to deploy pair bonding this week with plans to hit every market in all 22 AT&T states. AT&T is saying that bonded VDSL will help them reach more customers by extending service another 1-2,000 feet from the VRAD. With this extended reach, AT&T says they'll be able to pass 30 million homes by end of 2011, up from around the 24 million mark now. Note that AT&T originally promised to reach 30 million homes much earlier, but scaled back U-Verse ambitions.

Despite recent statements (apparently for political show) that AT&T was testing 80 Mbps, AT&T is saying their pair bonding won't actually result in speed boosts for performance. Bonded VDSL can technically provide a slight speed boost of around 25-30%, but it might wind up being assigned to HD video, and not necessarily broadband speeds. That means the very fastest speed AT&T offers (assuming you're even in range) will be 24/3 Mbps. Comcast and cable companies embracing DOCSIS 3.0 should appreciate that.

The good news though is that if you were just out of range of AT&T's U-Verse -- that might be changing soon. To offer bonded VDSL, AT&T needs to assign two DSLAM ports to each customer, and deploy a special residential gateway outside the house that can terminate two pairs -- assuming they're available. This still doesn't address AT&T's competitive lack of high-end speed, though AT&T's likely assuming they can either deploy a faster DSL variant down the line.

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