IMS Diameter Stack

a powerful software tool

The Softil Diameter Toolkit is a powerful software tool designed for the development of IMS Diameter-compliant network elements. It includes all the required development components, including a set of quick start sample applications that demonstrate efficient API usage, a GUI test application and detailed documentation.

Key highlights

IMS 3GPP and TISPAN Compliancy

Implements all major IMS interfaces and is IETF RFC 3588-compliant. It allows seamless integration with IMS-based IP networks (3GPP and TISPAN).

Flexible Modular Architecture

Used to develop both client and server applications. It is equipped with API hooks that allow the application layer to control call flows and objects inside the Toolkit for enhanced application capabilities.

A part of the complete IMS Development Environment

A critical component of Softil’s IMS Developer Suite, which includes all the signaling and media protocol toolkits and products to easily and cost-effectively meet the IMS challenge.

Did you know?

Softil’s Diameter Stack has over a dozen IMS Interface modules.

The user application is built on top of one or more Signaling Toolkits, and is plugged on top of the STUN NAT Traversal stack. The STUN NAT Traversal stack enables STUN negotiation and uses signaling and RTP stacks for the actual call/dialogue.

The Diameter stack provides multiple layers of APIs including:
  • High-level APIs that hide the complexity of the protocol and enable rapid development of applications
  • Mid- and low-level APIs that expose the internals of the protocol and allow for more power and customization based on application requirements
  • The Diameter stack follows the protocol’s layered architecture and has a Diameter Base engine which runs over any reliable transport (TCP, TLS, SCTP, IPSec). All the specific IMS Diameter applications plug in as separate modules above it


The Diameter Stack is rich with features, including:
  • Internally Multi-Threaded
  • Multi-Instance
  • Multi-core optimized
  • Full Capability Exchange
  • Watchdog Messages support
  • Session Initiation and Processing
  • Session Timers
  • Session Termination and Extensibility
Over a dozen internally supported IMS interfaces including:
  • Sh – Interface between an AS (SIP AS or OSA CSCF) and an HSS
  • Dh – Interface between an AS and an SLF
  • Rf – Offline Charging Interface between an IMS Network Entity or an AS and CCF
  • Ro – Online Charging Interface between an AS or MRFC and the ECF
  • Cx – Interface between a CSCF and an HSS
  • Dx – Interface between a CSCF and an SLF
  • Gq – Reference Point between an P-CSCF and a PDF
  • Gx – Interface between an PCRF (Policy and Charging Rules Function) and PCEF (Policy and Charging Enforcement Function)
  • Rx – Interface between a Charging Rules Function (CRF) and the Application Function (AF)
  • Px – Interface between an HSS and a Presentity (Presence Proxy)
  • Ph – Interface between an AS and a Presence Network Agent
  • Gy – Interface between a PCEF and an OCF
  • Gz – Interface between a PCEF and a CDF
  • Wx – Interface between the HSS and a AAA Server
  • S9 – Interface between HPLMN and VPLMN
  • S6a – Interface between MME and the HSS
The Diameter Stack comes with:
  • Full source code
  • Complete source code sample application
  • Full documentation, programmer’s guide and reference guide
  • Porting guide (for unsupported operating systems)
  • Training
  • Version upgrades
  • Professional customer support
  • Turnkey solutions (upon request)
  • Porting services (upon request)


The Diameter protocol is the industry recommended protocol for AAA functionalities (Authorization, Authentication, and Accounting).

Softil’s Diameter Stack provides all necessary AAA services. The Diameter Stack complies with the latest IETF (RFC 3588, RFC 3589, RFC 4006), 3GPP, and TISPAN IMS standards. Coded in ANSI C and cross-platform compatible, the SIP Stack is available for all common operating systems.


All Softil products and solutions take into account interoperability issues between disparate networks, protocols and devices. The SIP Stack has been thoroughly tested for full interoperability with other clients and servers.

Common Core

The Diameter Stack is based on Softil’s Common Core, an operating system abstraction layer specifically optimized for communication protocols and embedded platforms. This ensures easy portability of developed products between platforms and operating systems, including those not directly supported by Softil.

All Softil Protocol stacks and development platforms use the same common core. When using more than one Protocol stack in an application, one common core module serves all protocol stacks. This provides the following added benefits:

  • Ensures protocol co-existence
  • Reduces footprint
  • Boosts performance

Formerly Radvision IMS Diameter Stack, part of Radvision IMS Express

Softil IMS Diameter Toolkit Datasheet