Leave-in-Time: A Service Discipline for Real-Time Communications in a Packet-Switching Network

Leave-in-Time is a new rate-based service discipline for packet-switching nodes in a connectionoriented data network. Leave-in-Time provides sessions with upper bounds on end-to-end delay, delay jitter, buffer space requirements, and an upper bound on the probability distribution of endto-end delays. A Leave-in-Time session’s guarantees are completely determined by the dynamic traffic behavior of that session, without influence from other sessions. This results in the desirable property that these guarantees are expressed as functions derivable simply from a single fixed-rate server (with rate equal to the session’s reserved rate) serving only that session. Leave-in-Time has a non-work-conserving mode of operation for sessions desiring low end-to-end delay jitter. Finally, Leave-in-Time supports the notion of delay shifting , whereby the delay bounds of some sessions may be decreased at the expense of increasing those of other sessions. We present a set of admission control algorithms which support the ability to do delay shifting in a systematic way.