AT&T Is Capping Upload Data Speeds (Update: It's a Defect)S

Uh, this better be temporary. We gush about the iPhone 4's hot new upload speeds, and AT&T takes it away. Mobile upload speeds in several cities, like New York, are capped at 100kbps—1/10th of what we were seeing.

That's the reportage from MacRumors forums, and we're getting the same results in New York—zippy downloads, but upload speeds are stuck below 100 kilobits per second, a far cry from the 1500+ we were seeing a week ago.

And it does appear to be regional. Placed affected since this weekend, according to the forums:

NYC, Central Jersey, Boston, Orlando, Seattle, South Jersey/Philly, Columbus, Cleveland, West Houston, Phoenix, Northern Colorado, St. Paul/Minesota, Suffolk County/Long Island, Quad Cities, South Jersey, Denver, Detroit Metro, Cincinnati, Baltimore, Salt Lake City, Las Vegas, Kansas City, Fairfax, Minneapolis

(This is why my fireworks pictures took a long damn time to upload.)

It does appear to be a regional outage/restriction, since our tests in Chicago show the kind of upload speeds expected from the iPhone 4—1237kbps.

We've reached out to AT&T for comment, but the most likely explanation is an outage or maintenance work related to HSUPA (basically, the network protocol that allows faster upload speeds, toward the 1Mbps range) in these areas. In the meantime, there's no word on when the pipes will open back up—hopefully soon.

Update: An official comment from AT&T is incoming, supposedly.

Update 2: The official cause of the problem, according to AT&T is a software defect in Alcatel-Lucent's equipment:

AT&T and Alcatel-Lucent jointly identified a software defect — triggered under certain conditions – that impacted uplink performance for Laptop Connect and smartphone customers using 3G HSUPA-capable wireless devices in markets with Alcatel-Lucent equipment. This impacts less than two percent of our wireless customer base. While Alcatel-Lucent develops the appropriate software fix, we are providing normal 3G uplink speeds and consistent performance for affected customers with HSUPA-capable devices.