pdf_gross.gifIMS and SIP Signaling – VoLTE

[2-day course, Euro 2,350.- (net) per participant]

Course Description

IMS Architecture Overview

  • IMS in the overall Network Architecture

  • The IMS in the 3GPP Architecture (Network Perspective)

  • And what is inside the IMS?

  • What is VoLTE?

  • VoIP

  • VoLTE

  • IP Multimedia Subsystem (IMS)

  • Rich Communication Suite (RCS)

  • MMTel

  • VoLTE Network details in the context of LTE

  • Control Plane / E-UTRAN – EPC

  • User Plane E-UTRAN – EPC (S5/S8 GTP-based)

  • SIP / SDP Transport Details

  • The Mobile’s Way to SIP Registration and SIP-Sessions

IMS with LTE

  • Attachment through E-UTRAN / new MME

  • Bearer Concept & QoS-Architecture in SAE

  • SAE-Bearers, Classification and Policy Enforcement

  • The QoS-Profile of the SAE-Bearer

QCI – QoS Class Identifier, GBR – Guaranteed Bit Rate, MBR – Maximum Bitrate, AMBR - Aggregate Maximum Bit Rate (APN-AMBR, UE-AMBR), QCI-Values and their Meanings, Mapping between Rel. 8 QoS and earlier Releases (QCI – QoS Class Identifier, )

  • Dedicated EPS Bearer Establishment

  • Network Initiated (IMS triggered during Call Establishment)

Initial Conditions, Detailed Description of PDN-GW & PCRF interworking

  • Example for VoIP-IMS in LTE – S1-MME/UserPlane

Three EPS Bearers for a Voice Call?, Example for Traffic Flow Template (TFT) – QCI 5, Example for Traffic Flow Template (TFT) – QCI 1

  • Security in LTE

Architecture Internals and IMS Operation

  • Basic Architectural Elements

  • Generic SIP-Network Architecture

  • Typical User Agents of the IMS

  • SIP Messaging between User Agents

  • IMS-related Identities

  • Public User Identities

  • Private User Identities

  • Service Identities

  • Private User Identity (IMPI) / Public User Identity (IMPU)

Overview / the ISIM, Private User Identity (IMPI), Public User Identity (IMPU)

  • Details of Private User Identities (IMPI)

  • Details of Public User Identities (IMPU)

  • Use of Private and Public User Identities in REGISTER-Msgs.

Home Network Domain Name, Use of Private User Identity, Use of Public User Identity, Use of Temporary Public User Identity

  • Relationship between Private and Public User Identities

  • Server Types (generic)

  • Special Server Types (generic)

  • IMS – the Detailed View

  • P-CSCF – Tasks & Functions

  • Typical Use Cases

Security Association Details

  • P-CSCF Interworking with the TrGw

  • Facts Sheet

  • I-CSCF – Tasks & Functions

  • Typical I-CSCF Use Cases

  • I-CSCF Involvement during UA Registration

  • I-CSCF Involvement during IMS-Incoming Transactions

  • Topology Hiding through the I-CSCF

  • Facts Sheet

  • S-CSCF – Tasks & Functions

  • Typical Use Cases of the S-CSCF

  • Registration Overview

  • Detailed IMS Registration

3rd Party Registration

  • Involvement during IMS-Originating Transactions

  • Involvement during IMS-Terminating Session

  • Service Architecture and Routing

  • Routing Selection with Initial Filter Criteria

  • Example: Initial Filter Criteria and Trigger Point Configuration

  • IMS Routing Scenarios (Examples)

  • IMS Routing Scenarios (Examples) (cont’d)

  • Facts Sheet

  • BGCF – Tasks & Functions

  • Use Case of the BGCF

  • Facts Sheet

  • MGCF / MGW (IMS-MGW) – Tasks & Functions

  • Typical Use Cases of the MGCF and the IMS-MGW

  • Involvement during IMS-MOC towards PSTN or CS-Domain

  • Facts Sheet

  • Facts Sheet

  • MRF – Tasks & Functions

  • Typical Use Case: Announcement Playing

  • Facts Sheet

  • Facts Sheet

IMS Protocols and Messages

  • SIP and SDP

, Session Establishment, Clarification of the Term “Session”, Session Modification, Session Release

  • Session Setup Example through SIP

  • Some SIP-Terminologies

Message Types, SIP-Methods, Response Types

  • SIP-Message Format

General Information, Request Messages, , Response Messages

  • Selected SIP Header Parameters

Example: SIP Logfile with Header and Routing Info

  • Transaction Identification (two UA’s / no Proxies)

The Cseq Parameter , The Branch Parameter, Magic Cookie "z9hG4bK", Example: Transaction Identification (Sequence Numbering (CSeq))

  • Dialog Identification (two Users / with or w/o Proxies)

Session Identification and Distinction

  • Session Description Protocol

  • The Offer / Answer Model

Example: SIP Logfile with SDP Parameter Definitions as Payload

  • Introduction to other important IMS-related Protocols

  • Introduction to the DIAMETER Protocol

  • IMS-specific Amendments to DIAMETER Protocol

  • Architecture Overview

Overview of IMS Specific Messages

  • SIP Session Setup and Diameter Relation – Principles

  • Review of RTP / SRTP / RTSP / RTCP

  • Operational Overview of RTP and RTCP

SSRC (Synchronization Source / 32 bit), CSRC (Contributing Source / 32 bit), Timestamp Information

  • RTP / RTCP

  • Review of the RTP Header Format

Version, P-Bit (Padding), Ext-Bit (Header Extension), , CSRC-Count, M-Bit (Marker), Timestamp, Synchronization Source (SSRC), Contributing Source (CSRC), Extension Header, Payload Type, Sequence Number

  • IMS Mandatory Media for VoLTE Services – UE View

  • Tasks and Functions of RTCP

Quality Report Transfer, Session Control, CNAME <=> SSRC Binding

  • Example of an RTCP-Frame (Sender Report)

Gateway Architecture, Scope of H.248

  • Contexts and Terminations

Terminations, Contexts

  • The H.248 / MEGACO Command Set

Notify, Service Change, Add, Modify, Subtract, Move, Audit Value, Audit Capabilities, Example of Media Gateway Operation through H.248

  • DNS-Queries in the IMS-Environment

  • ENUM

  • IPsec

IPsec in Tunnel Mode, The IPSec Authentication Header (Next Header (8 bit), Payload Length (8 bit), Reserved (16 bit), Security Parameters Index (SPI) (32 bit), Sequence Number (32 bit), Authentication Data (n bit)), The IPSec Encapsulated Security Payload (ESP) Header (Security Parameters Index (SPI) (32 bit), Sequence Number (32 bit) , Payload Data (n bit), Padding (0 – 255 octets), Padding Length (8 bit), Next Header (8 bit), ESP Authentication Data (n bit))

Selected Services over IMS

  • VoLTE and the Alternatives


  • CSFB


  • VoLGA

  • FEMTO / PICO Cells

  • Over The Top (OTT)

  • IMS

  • The Voice Evolution

  • Circuit Switched Fallback (CSFB)

The SGs Interface, CSFB Procedures, Handover or Redirection, Delay Values, Call Setup Success Rate

  • Single Radio Voice Call Continuity (SRVCC)

  • SRVCC in Release 8

  • Enhanced SRVCC

Architecture in case of IMS-based Voice Services (SRVCC)

  • IMS based VoLTE – A Brief Comparison

  • IMS Centralized Services

  • Architecture for IMS Service Centralization and Continuity

SCC AS , UE (normal or enhanced for ICS), MSC Server (normal or enhancements for ICS), IMS registration via CS access

  • IMS MMTel Overview

  • VoLTE – The Service Overview

  • Generic IMS Functionality

  • SIP Registration

  • Authentication

  • Addressing

  • Call Establishment and Termination

  • Forking

  • Tracing of Signals

  • Use of Signaling Compression

  • Overview of IMS Supplementary Services

  • Overview

  • Supplementary Service Configuration

  • Ad Hoc Multi Party Conference

  • Communication waiting

  • Message Waiting Indication

  • Originating Identification Restriction

  • Terminating Identification Restriction

  • Communication Diversion

  • Communication Barring

  • Call Setup and SMS over IP Functionality

  • Call Setup Features

SIP Preconditions, Loss of PDN Connectivity, Loss of Media Bearer and Radio Connection, Voice Media, Multimedia

  • SMS Over IP

  • IMS Required Media Support

  • Codecs

  • RTP Profile

  • SDP Offer

  • Data Transport

  • RTCP

  • DTMF Events

  • Radio and Packet Core Feature Set

  • ROHC Profiles

  • LTE Radio Bearer Configurations

  • Bearer Management

  • P-CSCF Discovery

  • IMS Common Functionality

  • IP Version

  • Emergency Service

  • Domain Selection

  • Rich Communication Suite (RCS, RCS-e, Joyn)

  • Roaming Considerations

Interworking with PS CN, Target Voice Roaming Architecture

Access network specific signaling , Session Establishment Signaling – SIP / SDP , Diameter Signaling, Media Stream

  • SMS Handling

The SMS Service