Honey Bee Algorithm for Allocating Servers
December 26, 2007
I came across an interesting article in The Hindu (see the story from GaTech news; I couldn’t find the link on The Hindu website) today which described work done by Sunil Nakrani and Craig Tovey, researchers in GaTech, on using a decentralized profit-aware load balancing algorithm for allocating servers for serving HTTP requests for multiple hosted services on the Web. The interesting, thing is that the algorithm is based on how Honey Bees in a bee-hive decide where to collect nectar from. I decided to take a look at the paper.
Essentially, the forager bees collect information about how profitable a particular nectar source and how much is the cost involved in collecting from that source (round trip time). Based on a composite score, they perform a waggle-dance which essentially indicates what is the value of performing foraging where they have been. The inactive foragers can thereafter figure out where to go look for nectar.
The researchers modeled it in the server space by having an advert-board, where servers post profits from serving a request and the time required to serve it. Thereafter, the other servers can choose which colony (or service) they wish to be a part of. Existing servers can also move to another colony based on a probability determined from a look-up table indexed by the ratio of their profits by the profits of their colony.
Their results indicate that they do quite well compared to optimal-omniscient strategy (which knows the pattern of all future web requests) and better than existing greedy and static assignment strategy. Shows that we still have a lot to learn from nature!
One thing that flummoxed me though was that the original paper seems to have been published way back in 2003 (see Tovey’s publication page). I wonder why it got press publicity only now.
[The paper also cites a Harvard Business Review paper titled Swarm Intelligence: A whole New Way to Think About Business]