In ITU-T standards for asynchronous transfer mode (ATM), a class of traffic supported by ATM Adaptation Layer 1 (AAL1). Such traffic is connection-oriented constant bit rate (CBR) Class 1 Class 2 Class 3 Class 4 Class 5 High-Usage Group Regional Center Sectional Center Primary Center Toll Center End Office traffic that must be timed between the source and the sink. Class A traffic is stream-oriented and intolerant of latency. See also
AAL,
AAL1,
ATM,
CBR,
connection-oriented,
ITU-T,
latency,
sink,
source, and
stream-oriented.