In this paper, we evaluate the performance of zone-based registration. First, we propose a mobility function for single zone-based registration. And we establish the circumstances of multiple zone-based registration, which is based on the mobility function for single zone-based registration, and perform simulation programs for the circumstances. Using the simulation results, we obtain optimal N, the number of multiple zones which minimizes signalling traffic in radio channels. Results show that in most cases optimal N is 2. Multiple zone-based registration has less signalling traffic in radio channels than single zone-based registration and zone-based registration must be implemented as multiple zone-based registration.