The Ytarran teleportation network was a planned network of teleporters created by the Ytarrans (hence the name). Despite the obvious logistical and military applications of the network, the plan was shelved after it was shown to be linked to the Astral Plague. Even if it had not been cancelled, the network would have gone uncompleted anyway due to said plague wiping out the entire Ytarran empire.
At least two portals in the network were contructed (at Ginaron and Polaron) and VII's transit proves that they were operational. These portals were key to Epsilon's plan to eradicate organic life from the continent and were also sought after by Kua Commander, although it is as yet unclear how he knew about them.