Most sensor networks, including our previous designs, use specialised protocols to transfer data or control nodes. Web technologies such as HTTP servers are not ideal for small devices with little RAM etc but with a minimal implementation they provide a much more standard technique to communicate with nodes.

In the first year we used a small web server on each node capable of replying to GET requests with the minimal amount of data (not like normal web pages). This means a web browser attached to the network can view/setup nodes directly. The low data rate of the network also makes fetching web pages via a few hops quite slow but it is one way to introduce more standardisation.

The nodes themselves used a web POST to send the binary data out when they needed to. The satellite network link from the border router can introduce a long latency so we have made a POST proxy on the micro-PC there which passes the data onwards to the database/server. This means the nodes know their data is safe once it reaches the Estate buildings. A low-level approach to this is being investigated using Delay Tolerant Networking.

Our later deployments moved away from HTTP towards CoAP which is much more suitable for this type of network.