Here is what I wrote on March 1, 2003 on the subject of "Wireless Mesh Networks." Robert Poor is CTO of Ember Corporation. He contends that point-to-point or point-to-multipoint networks typical of industrial wireless communications systems have limited scalability and reliability. "In contrast, wireless mesh networks are multihop systems in which devices assist each other in transmitting packets through the network, especially in adverse conditions. You can drop these ad hoc networks into place with minimal preparation, and they provide a reliable, flexible system that can be extended to thousands of devices." The article is pretty technical and contains several illustrations and a case study about the deployment of a wireless mesh network in a water treatment plant. Check this column for Poor's conclusions or read this Sensors article if you have more time.