The protocol provides AAA (authentication, authorization, accounting) services that form the basis for the administration of services in telecommunications. For example, they are used to make decisions about access to user services, the level of quality of service (QoS) and the price of services.
How the Diameter Protocol Works
Depending on the network architecture, the node implementing the Diameter protocol can be a client or a server.
The Diameter protocol focuses on the application layer. AAA nodes receive confirmation or denial of access for any message transmitted between nodes, and TCP and SCTP provide reliability.
Diameter is used in LTE and IMS network-side functions, including the policy and charging rules function, the home subscriber server and the online charging system elements.
What the Diameter Protocol is for
Diameter monitors which services and resources are used on the network and helps to improve the security of the domain name system. Diameter has been selected as the AAA protocol for all fixed and mobile networks since the introduction of IP-based technology. Diameter is the backbone of the Evolved Packet System (EPS) network, which supports LTE technology.
The Diameter protocol has been adopted by many standardization bodies, such as 3GPP and ETSI NFV, as the basis for all AAA functionality in NGN (Next Generation Network). Diameter supports 4G updates, such as real-time transaction functionality.