Following is a list of known wormhole types:
Mankind discovered natural hyper travel accidentally by stepping through a naturally stable wormhole opened between our solar system and Alpha Centauri. Since then, scientific progress allowed mankind to locate, explore and replicate (at small scale and for short distances) these anomalies to its own gain.
Wormholes are natural (or artificial) occurrences that bind 2 points of space together, making travel between them quasi-instant.
Class A (natural) – Stable wormholes.
These wormholes have an apparently unlimited life span and tie 2 fixed points of space together.
Maximum jump distance 5 light-years
Class B (natural) – Unstable, patterned wormholes.
These wormholes modify the points they connect by changing their frequencies. However, the points (destination and start) that they connect can be predicted and calculated periodically.
Maximum jump distance 10 light-years
Class C (natural) – Unstable, un-patterned wormholes.
These wormholes change their operating frequencies so much that their destination, or even the times in which they open or close are impossible to predict. Use of this kind of wormholes is extremely dangerous.
Maximum jump distance 15 light-years
Class D (generated) – Temporarily stable wormholes.
Also known as hyper clouds, these wormholes are man-made, for intra-system travel. Ships with wormhole generators can virtually teleport around for short distances, with severe penalty to their energy supplies. There is no way for a ship (by using current technology) to travel distances longer than 1 light year by using a self-generated wormhole. Inter-system travel is still done through Class A wormholes.