Stanford biologist and computer scientist discover the ‘anternet’

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On the surface, ants and the Internet don’t seem to have much in common. But two Stanford researchers have discovered that a species of harvester ants determine how many foragers to send out of the nest in much the same way that Internet protocols discover how much bandwidth is available for the transfer of data. The researchers are calling it the “anternet.”


Deborah Gordon, a biology professor at Stanford, has been studying ants for more than 20 years. When she figured out how the harvester ant colonies she had been observing in Arizona decided when to send out more ants to get food, she called across campus to Balaji Prabhakar, a professor of computer science at Stanford and an expert on how files are transferred on a computer network. At first he didn’t see any overlap between his and Gordon’s work, but inspiration would soon strike.

“The next day it occurred to me, ‘Oh wait, this is almost the same as how [Internet] protocols discover how much bandwidth is available for transferring a file!’” Prabhakar said. “The algorithm the ants were using to discover how much food there is available is essentially the same as that used in the Transmission Control Protocol.”

Transmission Control Protocol, or TCP, is an algorithm that manages data congestion on the Internet, and as such was integral in allowing the early web to scale up from a few dozen nodes to the billions in use today. Here’s how it works: As a source, A, transfers a file to a destination, B, the file is broken into numbered packets. When B receives each packet, it sends an acknowledgment, or an ack, to A, that the packet arrived.

This feedback loop allows TCP to run congestion avoidance: If acks return at a slower rate than the data was sent out, that indicates that there is little bandwidth available, and the source throttles data transmission down accordingly. If acks return quickly, the source boosts its transmission speed. The process determines how much bandwidth is available and throttles data transmission accordingly.

It turns out that harvester ants (Pogonomyrmex barbatus) behave nearly the same way when searching for food. Gordon has found that the rate at which harvester ants – which forage for seeds as individuals – leave the nest to search for food corresponds to food availability.

A forager won’t return to the nest until it finds food. If seeds are plentiful, foragers return faster, and more ants leave the nest to forage. If, however, ants begin returning empty handed, the search is slowed, and perhaps called off.

Written By: Bjorn Carey
continue to source article at engineering.stanford.edu

4 COMMENTS

  1. I can’t comment about the substance of the article, but the blue gelatinous material in the photo reminded me of the gift I received a few years back: an ant farm with harvesters. It was a fascinating spectacle to behold each day as the ants made their tunnels. I remember the last ant alive who lived about 30% longer than all the others. Perhaps there is a simple, known answer for his (presumably) longevity; I wished it could have been analyzed. I still think of that ant!

    Mike

  2. Nitpick.  TCP/IP is not a file transfer protocol.  It is streaming protocol.  FTP or sometimes HTTP is a file transfer protocol piggybacked on top of TCP/IP.  TCP/IP is not quite a clever as anternet.  It just sends out a new packet as soon as an ack returns.  It has a “window”.  It can send out N packets before it blocks waiting for an ack.  It is actually somewhat more complex than that.  It is one of the greatest ideas in computing.  It is very simple as protocols go, incredibly extensible, robust, and if the lines are good quality, quite efficient.

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