Increased Video traffic necessitates AT&T to cap DSL Internet + U-Verse

According to, AT&T will implement a 150GB monthly cap on DSL customers and a 250GB cap on subscribers to U-Verse high speed Internet access starting on May 2, 201. AT&T will charge overage fees of $10 for every additional 50GB of data, with two grace periods to start out — in other words, the third time you go over the cap, that’s when you’ll get charged.

AT&T explains it will only impact two percent of consumers who use “a disproportionate amount of bandwidth,” and poses the caps as an alternative to throttling transfer speeds or disconnecting excessive users from the service completely. Customers will be able to check their usage with an online tool, and get notifications when they reach 65 percent, 90 percent and 100 percent of their monthly rates.

For more information:

Here’s the AT&T statement attempting to justify the data caps and overage charges:

“We are committed to providing a great experience for all of our Internet customers. Less than 2 percent of our Internet customers could be impacted by this approach – those who are using a disproportionate amount of bandwidth. We will communicate early and often with these customers so they are well aware of their options before they incur any additional usage charges.

The top 2 percent of residential subscribers uses about 20 percent of the bandwidth on our network. Just one of these high-traffic users can utilize the same amount of data capacity as 19 typical households. Lopsided usage patterns can cause congestion at certain points in the network, which can slow Internet speeds and interfere with other customers’ access to and use of the network. Our new plan addresses another concern: customers strongly believe that only those who use the most bandwidth should pay more than those who don’t use as much. That’s exactly what this does – and again, 98% of our customers will not be impacted by this.”

Opinion: I expected data caps to happen late last year, with all the video streaming, uploads and downloads. Apparently, most of the streaming is from people streaming Netflix videos to their converter boxes- TVs.

Note, that ATT’s U-verse and ADSL-based Internet access are completely different transport architectures:

  • U-verse is all IP over Ethernet (frame format) with fiber to the cabinet/node and VDSL2 to the subscriber- shorter copper loop than conventional DSL Internet access.
  • ADSL Internet is IP over PPP over ATM AAL5 over ADSL (or ADSL2+) from the CO or Digital Loop Carrier to the subscriber (much longer copper loop).

Here’s an article comparing triple play delivery networks, highlighting AT&T U Verse (based on an IEEE ComSoc SCV officer tour of AT&Ts U Verse Labs in San Ramon, CA last summer). Readers may find it informative if not enlightening:

As far as we know, Comcast is NOT capping its high speed Internet traffic- either for residential or business customers. And they offer higher speeds than AT&T U-Verse or DSL Internet.

Note:  The author has had AT&T (SBC, Pac Bell) DSL based Internet access since 2001, which was only upgraded to 2.5 M bit/sec a few years ago. It is much slower than DSL access in other countries, let alone what Comcast and other MSOs are offering for the same service.

Author Alan Weissberger

By Alan Weissberger

Alan Weissberger is a renowned researcher in the telecommunications field. Having consulted for telcos, equipment manufacturers, semiconductor companies, large end users, venture capitalists and market research firms, we are fortunate to have his critical eye examining new technologies.

9 replies on “Increased Video traffic necessitates AT&T to cap DSL Internet + U-Verse”

Thanks for writing this article, Alan. Comcast has a 250 Gbyte limit that is somewhat elastic in terms of enforcement. What happens is that one will get a call if they exceed 250 Gbytes. They will warn you that you need to cut back. If it happens twice in a 6 month period, then you will be subject to termination.

They suggest that 99% of the users never hit the 250 Gbyte mark. It also isn’t clear whether or not the 250 Gbyte includes the aggregate of both the upload and download or whether it is just the downstream.

I don’t know anyone who hits this Comcast data limit. Was it due to Bit Torrent FCC ruling which was subsequently reversed by US Federal Court?

I am sure the original Bit Torrent-FCC ruling and the data caps were related, as timing was such that the order came out August 1, 2008 and the bandwidth policy was put in place on October 1, 2008.

According to Comcast 1% or less reach the limit. I consider my household to be a heavy user and we have only hit 50+ Gbytes per month, thus far.

What a load of c***.
Caps are a cash cow for these companies.
Plus they know people who can watch tv for free online won’t pay big bucks for their ppv.Or even cable.
Better be careful with your internet minutes!!!!
I thought those days were over….

An IEEE ComSocSCV Discussion Group member writes:
In the DSL based Internet access model, the data is transmitted over twisted pair to the DSLAM in the telco central office. The amount of traffic flowing on the twisted pair does not affect their costs. Their costs with data traffic only from the DSLAM on. The telco does not see an impact on their infrastructure until they get to the CO. The CO is their first sharing point.

Same with uVerse – they use VDSL into the VRAD, where they go to fiber. Actually in the case of uVerse they might be doing some concentration at the VRAD so their costs would start to rise at that point. The VRAD is their first sharing point.

The cable situation is different because sharing starts right at your house.

So unless I am missing something, the lower cap should be on vVerse, not DSL. But uVerse is a premium service, so maybe that is why they cap it higher.

As we know, pricing, caps, etc are based on perceived value, not cost! (ie SMS selling price!)

Even Larry Lessig has come out in favor of usage based pricing. Without it you have the tragedy of the commons. (and you have sloppy network access protocols like the first generation of the iPhone.)

Alan’s Reply: I certainly can’t justify ATTs DSL/ U Verse based pricing policy. What you write about shared data traffic is correct. All DSL copper loops are dedicated pt to pt links rated at a top transmission speed. But the DSLAM/ VRAD uses statistical multiplexing such that the sum of the peak rates of all the DSLs <<< the uplink/downlink of the multiplexer.Congestion occurs when to many individual DSLs are streaming/ downloading/ uploading videos or large files. This occurs at the network node where the MUX is located, either in the cabinet (U Verse) or central office (ATM over DSL based Internet access).One motivation for data caps is to reduce individual line rates to alleviate potential congestion at the network node. With more and more folks streaming, uloading and downloading videos, incidents of congestion would otherwise increase.At the Mar 9 ComSocSCV meeting, it was revealed (by ASSIA Inc) that the Downstream: Upstream traffic ratios for all types of DSL access is now about 2:1 (vs 8:1 a few years ago). This implies that both the mux uplink as well as the downlink might experience congestion.

Great explanation of why AT&T (and soon other) DSL based Internet providers may impose data caps and overage charges!

Netflix is not at all pleased about AT&T’s decision to cap data use on fixed Internet connections

Consumers Union objects to AT&T data caps:
“The data usage caps and subsequent overage charges will limit consumer choice and add to the ever-increasing costs of Internet access for consumers,” wrote Consumers Union policy counsel Parul Desai.

The caps is a must to keep the quality of AT&T broadband service in my opinion. So, users should really careful to review their needs when choose a Broadband service in future.

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