The course explains SIP (Session Initiation Protocol), describes the IMS nodes and architecture and how LTE/EPS serves as an IP-CAN (IP Connectivity Access Network) as described in 3GPP specifications and GSMA (GSM Association) documents. The course also outlines how IMS interworks with other networks, e.g. for fixed and mobile traditional circuit switched telephony.

Throughout the course, message-level signalling flows are shown to illustrate various traffic cases, procedures and scenarios.


General knowledge about the architecture, terminology and modes of operation of the GSM/UMTS/EPS networks is highly recommended. Basic knowledge of IP networks and protocol stack is recommended. For required background knowledge, we recommend LTE/EPC System Overview.

3GPP System Overview

  • 2G and 3G radio and core networks
  • LTE/EPS nodes, architecture and mode of operation
  • IMS architecture and motives for IMS
  • CS and PS voice scenarios

SIP – Session Initiation Protocol

  • SIP nodes and network architecture
  • User Agent, Proxy Server, Registrar and Location Service
  • SIP Identities
  • SIP Methods – requests and responses
  • SDP, RTP and RTCP
  • SIP Traffic Case

IMS – the IP Multimedia Subsystem

  • Multimedia over IP using SIP
  • IMS nodes and architecture
  • IP-CAN, CSCF (Call Session Control Function), HSS (Home Subscriber Server) and AS (Application Server)
  • IMS subscriber identities
  • Basic IMS traffic cases; Registration and Invitation

Attach and PDN Connection Setup in LTE/EPS

  • IP-CAN: How the terminal connects to IMS
  • Different EPS Bearers: Default vs Dedicated Bearer
  • LTE Attach for IMS
  • PGW selection and  PDN Connection to IMS

The IMS Profile for Voice and SMS

  • GSMA PRD IR.92
  • Requirements on UEs and networks
  • Call setup traffic case
  • Multimedia Telephony (MMTel)

Policy and Charging Control (PCC)  

  • PCC principles – what is it that PCC does?
  • Sessions, Bearers and Service Data Flows (SDF)
  • PCC nodes/functions (PCRF, SPR, AF and PCEF)
  • PCC for VoLTE

VoLTE Roaming and Interworking

  • Some Roaming and Interworking Scenarios
  • Local breakout vs home routed traffic
  • Interconnect scenarios

IMS Interworking with CS Networks

  • CS Fallback
  • SRVCC principles
  • Breakout to CS Domain: roles of ENUM, BGCF, MGCF and IM-MGW
  • Incoming call from CS Domain: Domain Selection

Duration: 2 days


Classroom training: $1730

Virtual classroom training: $1730

Recorded training: $1210 Buy now

We offer substantial discounts for group bookings, and we have corporate rates with most of the operators and equipment suppliers in the world.

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