This read-write up/down/testing INTEGER is the desired administrative state of the interface; all interfaces start in the down(2) state at system initialization and are subsequently changed to up(1) or testing(3) through management action or retained configuration. An admin uses this to deliberately administratively shut down or test a specific DS0 channel without physically disconnecting it. For example, setting this object to down(2) for a noisy DS0 channel would take it out of service administratively while investigation continues.