Minimum buffer size for overflow avoidance in ATM CBR/VBR connection multiplexing

Connection admission control (CAC) functions in asynchronous transfer mode (ATM) networks require that a traffic descriptor (TD) be specified at connection setup. Existing standards define rule based traffic parameters, from which worst-case proof bounds for cell arrivals of a compliant connection can be derived. The purpose of this letter is to establish the minimum amount of buffer space actually required to avoid buffer overflow in a multiplexer loaded by constant bit rate (CBR) and variable bit rate (VBR) connections, meaning that any smaller buffer can be overflowed with positive probability. The relevance of this result is to provide a definite benchmark for possible resource savings assessment of statistical multiplexing schemes.