Relate to the internet and IP/DNS

[nicklasb]

It could be considered a no-brainer to just add WiFi and UMTS as media and just start sending packets.
However, communication within Robusto is point-to-point, low energy and can gain significantly from being clearly isolated from the perils, complexity and data volumes of the internet.
It also cannot in any way depend on Internet connectivity or WiFi routers to function, and that would be quite easy to do by mistake.
Gateway:
For example, UMTS is therefore implemented as a service gateway, and provides clear services, like posting files using OATH2 or messaging using MQTT. These are services it shares not only with WiFi, but with an ethernet connection (given the LANs are WAN-connected of course).
Bridge:
For more private networks, a function would perhaps be to forward or ingest pubsub events to/from Signal K, or provide a simple web page with information.

So probably WiFi, Ethernet and UMTS should all rather implemented as LWIP suppliers to a service gateway or brigde.