High Quality Content by WIKIPEDIA articles! The Generic Cell Rate Algorithm (GCRA) is an algorithm that is used in Asynchronous Transfer Mode (ATM) networks to measure the timing of cells on Virtual Channels (VCs) and or Virtual Paths (VPs) against bandwidth and jitter limits contained in a traffic contract for the VC or VP to which the cells belong. Cells that do not conform may then be re-timed (delayed) in traffic shaping, or dropped or reduced in priority in traffic policing. Nonconforming cells that are reduced in priority may then be dropped, in preference to higher priority cells, by downstream components in the network that are experiencing congestion. Alternatively they may reach their destination (VC or VP termination) if there is enough capacity for them, despite them being excess cells as far as the contract is concerned: see priority control.