Stargate Network

The Stargate Network is a vast web of Stargates built by the Ancients which spans many galaxies allowing near-instant travel to other worlds for any intelligent species.

Behind the scenes
According to Joseph Mallozzi, the Destiny's gate seeding mission did not involve the Ancients trying to "set up shop in the neighborhood" and that it appeared that they were not interested in setting up a gate network similar to the ones found in both the Milky Way and Pegasus galaxies, which have DHDs.