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.

3.Diameter Protocol Stack Architecture


Figure 3: Architecture of Diameter Protocol Stack


The above shows the schematic of DIAMETER protocol stack architecture for application server in IP Multimedia subsystem (IMS).

  • Diameter base protocol: The Diameter base protocol provides basic services to one or more applications (also called functions) that each runs in a different Diameter instance.

  • Basic functionalities provided by base protocol are as follows: reliable transport, message delivery, Delivery of AVPs, Capability Negotiation, Error Notification, Accounting, and extensibility via new command codes and AVPs.

  • Diameter Client API (Application programming interface): This acts as the interface between the diameter base protocol and the diameter application.

  • Diameter application: Diameter application is an application specific protocol used for transfer of application specific functions and messages.

  • Diameter applications are namely as follows: NASREQ, EAP, Mobile IPV4, Credit Control and other 3GPP interfaces like Cx, Dx, Sh, Ro, Rf etc