The Æthernet is an method of instantaneous, intergalactic, ansible communication. It is the standard around which the HubNet and the many other subnets exist.
Hubs are not small enough to be personally portable, and require a fair amount of maintenance to keep them in working order.
Æthernet encryption is managed within each hub by a LeGuin device. During downtimes hubs will coordinate to other hubs within their network via swarm machine learning to generate an increasingly unbreakable encryption algorithm. The result is that Æthernet encryption is nearly unbreakable, but messages are longer and nobody is really sure how the encryption works anymore.
Æthernet hubs are not multithreaded and so send and receive messages one at a time. In networks with multiple hubs this is negligible, but if a colony with a single hub is suddenly bombarded with data the hub and its LeGuin device may short-circuit.
While the power consumption of an Æthernet hub is not difficult for stations and cities to supply, it is a prohibitive amount for colonies until they have advanced power generation in place.