Today many network operators and suppliers are developing control plane technologies for applications in the emerging optical network called All-switched Network in which multi-chassis optical switches (called Switch Chassis Systems) play an important role. In this paper, we present ways to evaluate the scalability of the control plane of a Switch Chassis System (i.e. SONET/SDH OC-48 cross-connect, non-blocking switching system with 256 OC-48 connections). A stochastic network model is developed for studying the scalability of the control plane of the system. Through the numerical analysis of simulations, we can derive the scalability of the control plane of the system with a scalable scenario in which the required mean system delay (QoS) can be maintained.