Call Setup Scenarios

Several general call scenarios can occur and they pertain to all cellular systems.
A few perturbations of the call scenarios are discussed here that are
driven largely by fraud-prevention techniques employed by individual operators.
Numerous algorithms are utilized throughout the call setup and processing
scenarios, which are not included in Figures 2-5, 2-6, and 2-7.
However, the call scenarios presented here provide the fundamental building
blocks for all call scenarios utilized in cellular.