AbstractCSMA protocols have been extensively studied under the assumption of an equilibrium condition. The results obtained in this manner provided useful insight for the development of packet radio and local area networks for the transmission of bursty data. The integration of isochronous and bursty traffic in the same network may, however, make the equilibrium assumption unrealistic, for example when fixed‐length frames are defined, only a portion of which is devoted to the transmission of bursty data according to a CSMA protocol. In such cases, it is necessary to study the protocol behaviours in fixed‐length time segments. This paper presents a technique for the analysis of slotted CSMA protocols in such an environment. Definitions for the transient throughput and transient average packet delay are introduced, and closed form expressions are derived for non‐persistent and 1‐persistent CSMA and CSMA/CD protocols with arbitrary distribution of the packet length. Numerical results help in the visualization of some interesting phenomena, peculiar to the CSMA operations in finite‐length