IMS Primer

in Training, public

IP Multimedia Subsystem, or “IMS,” architecture defined by the 3GPP group is designed to enable seamless deployment of applications across a core network based on the open standards of the Internet Protocol. IMS enables wireline, wireless, and cable operators to offer a new generation of rich multimedia services across both circuit switched and packet switched networking infrastructures. IMS defines an architecture of logical elements using SIP for call signaling between network elements and provides a layered approach with defined service, control, and transport planes.

This course presents a detailed overview of the 3GPP IMS & a brief overview of TISPAN IMS. A good knowledge of SIP would be beneficial for anyone attending this course.

Course Objectives
After completing this course, the audience will be able to:

  • Understand IMS architecture
  • Define IMS interfaces & nodes
  • Describe SIP Protocol
  • Explain IMS signaling procedures and protocols

Who should attend?
This is beginner level course and suitable for telecom professionals & students who have little or no understanding of IMS.


Course Contents
IMS Introduction

  • IMS Overview
  • IMS Benefits
  • High Level Requirements
  • IMS Applications

IMS Protocols

  • SIP
  • Diameter

IMS Networks Architecture

  • Reference Points
  • 3GPP IMS Network Configuration
  • Key IMS Concepts
  • Call Session Control Function (CSCF)
  • Proxy-CSCF (P-CSCF)
  • Interrogating-CSCF (I-CSCF)
  • Serving-CSCF (S-CSCF)
  • Breakout Gateway Control Function (BGCF)
  • Multimedia Resource Function (MRF)
  • Home Subscriber Server (HSS)
  • Signaling Gateway (SGW)
  • Media Gateway (MGW)
  • Media Gateway Controller Function (MGCF)

Interworking with Networks

  • Interworking Reference Model
  • Interworking Between IMS and PSTN
  • IMS Interworking with UMTS & LTE Networks

IMS Procedures & Signaling

  • Proxy CSCF Discovery
  • Registration Procedure
  • User Deregistration
  • End-to-End IMS Session Flow
  • Call Origination and Termination
  • IMS PSTN Session Flow


  • NGN Functional Architecture
  • NGN IMS Overview


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