Diameter
Read this article about the history of Diameter and why it was developed. What preceded Diameter as an authentication protocol? While you do not need to understand how Diameter authenticates, you should have a general idea of its authentication process.
6.Diameter Client API
6.1.Initialization API
Initialization API used to initialize the DIAMETER Client stack which performs in the
registration of the stack with TCA, allocate the memory for the stack resources and
configuration of the stack.