Diameter

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