In this paper, a detailed burst header packet (BHP) processing model is presented to characterize the BHP processing time at the switch control unit of optical burst switching ring network. The distribution function of the total BHP processing delay, which is used to configure offset time, is derived based on the proposed model by using central limit, large deviation, and phase-type distribution theorem-based methods, respectively. A simulation platform that takes the practical processing delay of BHP into consideration is developed to evaluate the efficiency of the proposed model and mechanisms. Different distribution function-based offset time configuration mechanisms are analyzed and compared with the fixed offset time configuration mechanism in terms of burst loss ratio for insufficient offset time and average offset time deviation. The results show the validity of our model.