Correlative update system

The correlative update system is a program with DHDs that tell when a Stargate has changed it's address. Because of stellar drift, the update system will cause a Stargate to randomly dial the other stargates to update it's location to inform them of where they are.

Ba'al used the update system to send Avenger to the other Stargates, effectively shutting down the Stargate network. Nerus later discovered a means of disabling the correlative update system, which Ba'al then intended to use to rebuild his empire.