How Carriers Hamstring Your Smart Phone

How Carriers Hamstring Your Smart Phone "Middlebox" study reveals slow downloads, battery drains, and security flaws.

By Christopher Mims Technology Review August 25, 2011

A team at the University of Michigan and Microsoft Research has uncovered, for the first time, the frequently suboptimal network practices of more than 100 cellular carriers.

By recruiting almost 400 volunteers to run an app on their phones that probes a carrier's networks, the team discovered, for example, that one of the four major U.S. carriers is slowing its network performance by up to 50 percent. They also found carrier policies that drained users' phone batteries at an accelerated rate, and security vulnerabilities that could leave devices open to complete takeover by hackers.

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An Untold Story of Middleboxes in Cellular Networks

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The article describes the phenomenon:

"Surprisingly, packets of data sent across this network are buffered by the carrier itself. This means that when a packet of data fails to make it to its destination-a common occurrence on noisy wireless networks-it cannot be instantly retransmitted, as it would normally be on the Internet. Instead, the sending device must wait a long time-on the order of seconds-for a time-out to alert it to the failure."

This sounds exactly like "bufferbloat", a negative effect on network performance which most have attributed to a misguided effort to reduce packet loss, not an effort to reduce total network throughput. I would not be surprised if the effect was more pronounced on mobile networks. I wonder if the authors of the study knew this, or whether this might be an appropriate time to apply the old saying "Never ascribe to malice that which is adequately explained by incompetence" (or maybe in this case excessively oversubscribed networks.)