A network is a load of physical hardware - things like switches, routers, and servers. All the devices in a network consume electricity and have embodied carbon. The internet is a network of such devices. It's typically run off the local energy mix or grid, however clean or dirty that is. As a result, any data sent or received over the internet emits carbon. The quantity of data sent and the distance it travels affect how much carbon is emitted. Networking is the sixth principle of sustainable software engineering.