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AT&T Users Already Complaining About Inaccurate Meters
Measuring From DSLAM Inflating Usage Numbers?
by Karl Bode 04:29PM Tuesday Mar 22 2011 Tipped by gvd See Profile
While the consumer response to AT&T's T-Mobile is generally negative, AT&T's fortunate in that the deal at least has shifted media attention away from AT&T's recent decision to start charging DSL and U-Verse users overages. Over the years as we've watched ISPs (especially in Canada) embrace metered billing, so enamoured with the potential new revenue -- they often forget to make sure their usage meters actually work (see: Cogeco. Bell), Judging from posts in our forums by AT&T users, AT&T's effort on this front so far isn't any better. Comparing AT&T's new meter system to their firewall and router logs, several users note that AT&T's meter is off -- by as much as hundreds of gigabytes:
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AT&T's data appears to be wholely corrupted. Some days, AT&T will under-report my data usage by as much as 91%. (They said I used 92 meg, my firewall says I used 1.1 Gigs.) Some days, AT&T will over-report my data usage by as much as 4700%. (They said I used 3.8 Gig, dd-wrt says I used 80 meg. And no, this day wasn't anywhere near the day they under-reported.)

AT&T's data doesn't add up. If I take AT&T's data, and add up the individual day's usage as provided by them the totals don't add up to the automatically calculated total for that date range! For example, for my account from February 18th to March 17th, AT&T says the total usage is 221GB down, 12.8GB up, 234GB total. But if I actually add up the individual days from feb 18th to march 17th, the totals are 206GB down and 11.95GB up, 217GB total! That's an 8% difference just adding up the daily totals!
Another user in the thread suggests that the discrepancy is because AT&T is measuring usage at the DSLAM, thereby creating unrealistic totals that incorporate PPPoE and ATM overhead:
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This is the problem. DSLAM's are layer 2 devices in the OSI model. Unlike Uverse which uses IPDSLAM the counters for an ATM based DSLAM are going to include the PPPoE overhead and ATM overhead. Conservative estimates would put PPPoE and ATM overhead at 30%. Of course it all depends on the type of data sent and the size of the packets. If AT&T is indeed pulling it's usage statistics from the DSLAM then they are billing customers for the overhead injected by their use of PPPoE (1500 - 8 = 1492) and for the overhead necessary to transport a packet over ATM (due to the minimum 53 byte atm cell size).
We've asked AT&T for confirmation and comment. While many ISPs say they want to be able to bill like a utility, you'd be hard pressed to find any that want to be regulated like one. In particular, no ISP wants government regulators confirming their meters are accurate, and no regulators in North America have the courage to demand it, leaving consumers alone to fend for themselves and try and keep their carriers honest. We'll note that AT&T is already facing a lawsuit for allegedly artificially inflating data usage and over billing wireless users.


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tim85254

join:2010-07-15

3 recommendations

Relevant state department of weights and measures...

Every deathstar user that doesn't have the option to quit should all write the attorney general in their respective state pointing out this inaccuracy.

These meters tie directly to the bill. They should not be treated any differently from the scale in the deli (has a state certified sticker that its accurate) or a gas pump.

Every bill that's inaccurate should be disputed too. Not just through the deathstar's complaint channels, but through attornies general.

Every time. Every bill. Make UBB cost these greedy bloodsuckers more than they ever dreamed it could.

That's the way to nip this usage-based-billing BS in the bud. When the attorney general of every state afflicted with the AT&T cancer raises questions of whether their meter could be certified - I bet that's when some suit at AT&T realizes "Oh, wait a minute, this is going to be really expensive to implement."