Diameter protocol was created on 1998 to be a successor of RADIUS protocol, the main goal was to create a protocol more secure and implemented on signalling network.
It can use TCP or SCTP at transport layer and as TLS and DTLS for transport layer security and it has a fail over mechanism using internal watchdogs.
It has another mechanism to discover peers and configure them in order to maintained the sessions bindings.
Diameter communicate as a client and a server
Diameter Protocol RFCs
- First RFC 3588
- Additional Updates RFC 5729, 5719, 6408
- The RFC 6733 made all other obsolete.
RFC 6733 Specifies
- Protocol Format
- Peer Connection
- User Sessions
Types of Nodes
Any device using the Diameter protocol stack.
A Diameter client is any device who trigger a request to a server requesting information about the user and its level of access on the local or roaming network (AAA).
Types of Diameter Clients
Handles AAA requests
Route messages without change them
Route a message and can change it
Just simple redirect the traffic
Converts into another protocol
DEA Diameter Edge Agent
Located at border network
DRA Diameter Routing Agent
Core network providing routing capabilities
Convert into another protocol
DSC Diameter Signaling Controller
Groups DEA / DRA / IWF into one single device.
Diameter type of Messages