Directed Diffusion: A Scalable and Robust Comunication Paradigm for Sensor Networks

This paper also talks about a coordinated communication of sensor nodes in a sensor network that requires low power. The idea is similar to the TAG paper in that no centralized server should receive all the data onces it makes a request, because this consumes too much power. Thus, they call it a data centric communication method, is basically that a requester requests the data by a named attribute, and then the request is propagated throughout the network, with nodes sending the request to its neighbors, and then receiving the data and caching it in the local nodes. The terms used in this paper i found very confusing, which made this paper very hard to read. Nodes send "interests" which are basically just requests, through the network. There is also a "gradient" which keeps track of the freshness of data that's stored in the local cache. The "gradient" also determines when to evict a data in its cache.

The testing of the paper didn't take into account of congestion. Another question i had along those lines was the issue of the caches. It seems like if a lot of requests are made through certain nodes, the data caches will be filled up very quickly, and they would need to evict data that's requested. Especially if data is cached along the path from the source to the sink, certain nodes will be in the path more than others. But overall the idea is similar to that of TAG, which is basically localized communication, and also allowing the nodes to process the data before propagating through the network to save messages which in turn saves power.