Embers of Empires
A jump gate is an enormous ring floating free in space. When it is activated, it can connect to another ring within its operating distance. While the rings are connected, anything traveling through the ring will instantaneously emerge at the other end point.
Operating a ring requires a huge expenditure of energy, and the connections can only be maintained for a short time. Systems with rings have elaborate traffic control systems, and queue ships into groups. Rapid transport across the galaxy require multiple trips through gates, and while each trip takes no time, the traffic control protocols slow the process considerably. A typical turnaround is six hours, but on some systems can be much much longer.
Not every world has a gate. Some worlds can only be reached by directly traveling there. This process is slow, and not without some peril. While warp space itself is fairly safe, entry and exit are not. Gravity has a profoundly large effect, and any debris hit while accelerating and decelerating can be devastating. As a result, most ships don’t go transluminal unless they are well away from the system star.
Traveling around a star system is usually done via subluminal drives. It’s slow. It can take days to move between planets, and up to a week to move out far enough to use the transluminal drives.
Portable jump drives
These are extremely rare. The technology can’t be replicated by Omnipotech (not for lack of trying), and is only in a few of the ships remaining from the Thousand Year War. Rumors persist that some bio-ships can develop this ability, but this has yet to be proven.
A typical journey uses transluminal drives to get to the nearest jump gate, then by repeated gate jumps to get as close to the target world as possible, then transluminal drives to finish the journey. Jump gates form a kind of highway system through the galaxy.
Since the war, many worlds that are far off of the gate network have lost contact with the rest of the galaxy.