The Extranet refers to the entirety of the interplanetary, interstellar and intershperical digital communications network. In practice, it refers to whatever fraction of the network is nearby enough for the communications lag to be deemed tolerable.

The Extranet is a decentralised network building on many layers of smaller independant networks, outlined below.

Planetary Networks (Worldnets)

These networks are the fastest and easiest to set up, with communication being facilitated by physical data cables connecting networked computers to each other. For the purposes of the Extranet, these are the smallest unit the net is devided into. Communications within a worldnet may or may not be considered Extranet communications depending on the region.

System Networks (Starnets)

These networks connect the various worlds, stations, industrial sites and space vessels within a single system. The most commonly used methods of data transport in these networks are tight-beam communications lasers and jump drive equipped data carriers moving physical data-carrying objects directly between major network nodes in a decentralised connection pattern.

Sector Networks (Sectnets)

Sectnets are comprised of a series of hubs serving as storehouses for information, which is arranged, compiled, and transmitted via various methods to the various starnets. A sectnet is rarely accessed directly by the average user except in the systems wherein such servers and services are present. Specialized data drones spend their entire operational lifetimes travelling from hub to hub, downloading and uploading data to conserve parity between the various sectors.

Sphere Networks (Spherenets)

The overarching infrastructure of the localized networks is grouped into one semi-standard nomenclature. The spherenet is not a single entity but many. Each of the constituent sectnets and their summary starnets in a sphere comprise a spherenet. It refers universally to the entire media and sharing environment of a sphere's various, interconnected networks.

The Galactic Network (Extranet)

Because it can take many years for all the individual networks to be updated with contemporary data, the extranet is the umbrella terminology for the galactic media that sends and receives the most relevant data available. That is to say that the communications equipment, data drones, hubs, and servers utilized are, in fact, the extranet proper. It is also the colloquialized sum of the networks.

To access the extranet is to access a starnet in common, modern parlance.

However, the Galactic Network at large is much more than merely an intellectual property. Within each connected sphere is a recognized set of mirrors which represent the latest data warehouses of each polity, species, or region. These are maintained under careful scrutiny and feature the greatest level of cyber security and error correcting possible to avoid malicious use.

Any communication above worldnet level will have to deal with a significant amount of lag, which may or may not be a significant issue depending on the task at hand. There exist several ways of dealing with this lag, such as extensive mirroring, caching, the 'keep talking' principle and the use of envoy programs.