Fiber Distributed Data Interface (FDDI) is a high speed local area network operating at 100Mbps using a fiber optic ring transmission medium. The purpose of this paper is to build a Petri net model for the FDDI media access control (MAC) protocol. This model is hierarchically integrated into the Petri net model of the two-phase commitment (2PC) algorithm. By simulating the composed Petri net model we evaluate the latency of the 2PC algorithm. The FDDI model is validated by comparing the data obtained from performance measures and the numerical results derived from simulation.