The Diameter Protocol - An Introduction

DIAMETER is an authentication, authorization, and accounting (AAA) protocol [1] which was created to replace RADIUS [2]. It consists of a Base Protocol defined in RFC 6733 (obseletes RFC3588) [3] and applications such as Cx/Dx, Gx and S6a extend the base protocol by adding new commands and Attribute Value Pairs (AVPs).

A good resource on the Diameter protocol can be found here.

Protocol highlights of Diameter

DIAMETER Applications

Example Diameter Command codes

  • AA-Request/Response (AAR/AAA) 265
  • Diameter-EAP-Request (DER/DEA) 268
  • Abort-Session-Request (ASR/ASA) 274
  • Accounting-Request (ACR/ACA) 271
  • Credit-Control-Request (CCR/CCA) 272
  • Capabilities-Exchange-Request (CER?CEA) 257
  • Device-Watchdog-Request (DWR/DWA) 280
  • Disconnect-Peer-Request (DPR/DPA) 282
  • Re-Auth-Request (RAR/RAA) 258
  • Session-Termination-Request (STR/STA) 275
  • User-Authorization-Request (UAR/UAA) 300
  • Server-Assignment-Request (SAR/SAA) 301
  • Location-Info-Request (LIR/LIA) 302
  • Multimedia-Auth-Request (MAR/MAA) 303
  • Registration-Termination-Request (RTR/RTA) 304
  • Push-Profile-Request (PPR/PPA) 305
  • User-Data-Request (UDR/UDA) 306
  • Profile-Update-Request (PUR/PUA) 307
  • Subscribe-Notifications-Request (SNR/SNA) 308
  • Push-Notification-Request (PNR/PWA) 309
  • Bootstrapping-Info-Request (BIR/BIA) 310
  • Message-Process-Request (MPR/MPA) 311
  • Update-Location-Request (ULR/ULA) 316
  • Authentication-Information-Request (AIR/AIA) 318
  • Notify-Request (NOR/NOA) 323
  • More Information

    More details on Valid8's Diameter Load Tester solution can be found at and Valid8's Conformance test solution can be found at


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