Back pressure

A pressure that can cause water to backflow into the water supply when a user's water system is at a higher pressure than the public water system.

A system resource monitoring feature on Exchange 2007 transport servers. When a monitored system resource, such as hard disk drive utilization or memory utilization, exceeds the specified threshold, the Exchange transport server stops accepting new connections and messages, and concentrates on delivering existing messages. When the utilization of the monitored system resources returns to normal utilization levels, the Exchange transport server is allowed to accept new connections and messages. [Exchange 2007]