Swarm Intelligence Routing for MANETs: Bees (2/2)
Dumb parts, properly connected into a swarm, yield smart results.
Bees, just like ants, use effective mechanisms for collecting food. Their behavior has inspired algorithms used to find optimal routes within MANETs/WMNs. Some of their best examples are BeeAdHoc and BeeIP.
The Idea behind bee-inspired routing for MANETs
Bees fly – ok we all know that. While flying lets you get to a food source faster, it also demands larger ammounts of energy. This means that bees can’t just go flying around looking for food: they need to save as much energy as possible.
For such reason, looking for food includes different procedures (and actors as well). First, a small number of bees fly to find food. When a bee finds a source, it returns to the hive with some of it. At this point, the bee ‘dances’ to get the attention of the other bees as they gather. Then, the bee shows them a sample of the food (it actually pukes it… Alright sorry, you didn’t need to know that). Finally, they can decide wether they’re going for more food or not. By following this procedure, bees reduce the (global) ammount of energy spent searching for food.
Here’s a video that explains it better:
Applying bee-behavior into MANET routing
Bee ad hoc routing works with Agents. Each node is treated as a hive. There are three types of agents: scouts, foragers and swarms. Scouts are basically (broadcast) packets that are sent to discover new paths, an ack-scout is sent back as a unicast to acknowledge a successful path. They also recruit foragers when the scout is back to the hive. Foragers receive the data packet from the transport layer and deliver to the destination. They use the metaphor of dance once they return to the source node. Swarms or Beewarms are used for explicity transporting foragers back to their source when there is no ACK in the transport protocol (eg. UDP). Consider the routing table as a dance floor where the bee agents provide the information about the quality of path they have traversed (watch the video!).
As of its architecture, it is basically divided in 3: *The packing floor : Interface to higher level layer transport layer; *Entrance: Interface to lower level MAC; *The dance floor: The hearth of the hive, maintains routing information (foragers).
I find very interesting how nature can give us ideas to create and innovate in topics such as MANET routing. By observing and emulating bee behavior in food search and production, a complex -yet effective- routing algorithm can be built for limited-battery devices that communicate inside a mobile ad-hoc network.
Here’s a more detailed explanation.