I don't think there are any affordable ip based lighting solutions. In the US, Z-Wave is probably the most affordable, but one would have to add an ip based gateway to bridge the Z-Wave network and the local area network. Non of these gateways are opensource and the Z-Wave protocol is also non-public.
For most things I rely on serial control and use serial port servers such as the Lantronix WiBox so that serial communications are over the network.
For most things I rely on serial control and use serial port servers such as the Lantronix WiBox so that serial communications are over the network.
example but is very simple.