In the Milky Way galaxy alone, there are many hundreds of nodes in the wormhole network that links the civilisations of the One Time. Most of the nodes are spread out along the galactic arms, though this pattern isn't a physical requirement, just a preference based on stellar density.

The nodes spread between habitable worlds, though the definition of habitable can vary from one culture to the next. Many colonies are entirely orbital, encircling gas giants or rock worlds with shining cities in space. Others are terrestrial, with towns and cities spread along coastlines and river basins, sometimes home to billions of sentients.

The distance between nodes tends to vary according to the age of that part of the network. Initially, wormhole gates are sent to habitable worlds, or those rich in useful resources. The navigation and selection of the gate ships is not entirely understood, since most of them date back to earlier generations, but they seem to be more than capable of finding suitable candidate worlds. These worlds will often be a few thousand lightyears apart, with a flight time of 50 to 100 years.

As a colony world expands and its technology approaches the norm for the One Time culture, so it begins to construct gate ships of its own, and populate neighbouring worlds. These ships aren't as capable as the large ships of the ancients, so their range is more limited, but a small network of nodes tens of lightyears apart sprouts out around the main node.

Within the Milky Way galaxy, the dominant cultures are the Tlal, the Kin and the Scree. The Tlal control the central core of the galaxy, and refuse entry to anyone else. They also manage many of the major nodes across the galaxy. The Kin have been the principle gate builders in the outer arms, and it was one of their gates which connected Earth to the One Time. The Scree are mostly colonists here, and generally avoid getting involved in politics unless it directly involves them.

The Rekila - Earth Arm

The part of the network where Earth is located begins at the social hub of Rekila in the Scutum-Centaurus arm of the galaxy, spreading along the Orion-Cygnus arm for a distance of around 15,000 light years until it reaches (and ends at) Earth.