The intelligent network (IN) architecture promises easy development and fast deployment of sophisticated telecommunication services. However, the centralization of service logic programs, call processing database, and other housekeeping functions at the service control point (SCP) node may create some bottleneck situations. The authors present queuing models for the SCP and study the behavior of the IN centered around the SCP by simulation. It is illustrated that such models can help identify bottlenecks and plan the capacity of the SCP. Although the models are not complex, useful insights into the system can be gained. The models can be reused in other studies, on the design and evaluation of congestion control schemes for IN.