In asynchronous transfer mode (ATM), the description of a traffic characteristic of a source endpoint. Traffic parameters include peak cell rate (PCR), sustainable cell rate (SCR), maximum burst size (MBS), maximum frame size (MFS), and minimum cell rate (MCR). A traffic descriptor is the entire set of traffic parameters associated with a source endpoint. See also ATM, endpoint, MBS, MCR, MFS, PCR, SCR, and source.