pdf_gross.gifVoLTE from A-Z

[3-day course, Euro 3,450.- (net) per participant]

Course Description

VoLTE Overview

  • What is VoLTE?

  • VoIP

  • VoLTE

  • IP Multimedia Subsystem (IMS)

  • Rich Communication Suite (RCS)

  • MMTel

  • VoLTE Feature Definitions in the Specifications

  • VoLTE Feature Definitions in the Specifications (cont’d)

  • VoLTE – Overall Logical Architecture

VoLTE UE, EPS, IMS, Operator Control Entities (DRA / DEA, PCRF, HSS), Application & Services (SCC-AS, TAS), IPX (ENUM, DNS)

  • VoLTE Architecture Overview – The Main Components, LTE / EPC (EPS)

IMS, PCRF – Policing, Application & Services

  • Important Services Related to VoLTE

  • IMS Service Centralization and Continuation (IMS-SCC)

  • IMS Multimedia Services (MMTel)

  • Single Radio Voice Call Continuity (SRVCC)

  • EPS Review – LTE Network Basics

  • Zoom into the Evolved Packet System (EPS)

RNC + NodeB = evolved/enhanced NodeB (eNodeB or eNB), Functional Overview of Core Network Elements within the EPC (MME, S-GW, PDN-GW, ePDG)

  • Functions of the eNB

Selection of MME at attachment, Scheduling of paging messages, Routing of user plane data to Serving GW, PDCP

  • Functions of the eNB (cont’d)

RRM/RRC, RLC, MAC, Complete L1 functionality

  • Functions of the MME

NAS signalling, Inter CN node signaling (3GPP networks), Security management

  • Functions of the Serving GW (SGW)

Termination of U-plane packets for paging reasons, Support of UE mobility anchoring by switching U-plane during inter eNB handover, Transport Packet Marking According to QCI, Mobility anchoring for inter-3GPP mobility, Packet routing and forwarding, Charging support, Lawful interception

  • Functions of the PDN GW

Termination towards of PDN’s, Policy enforcement, Charging support, DHCPv4 and DHCPv6 functions

  • Control Plane / E-UTRAN – EPC

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

  • SIP / SDP Transport Details

  • VoLTE Network details in the context of LTE

  • VoLTE Terminal

  • EPS Functions for VoLTE

  • VoLTE Policing

  • IMS Functions for VoLTE

  • VoLTE specific Application Servers

  • VoLTE Handover Provisions with Rel. 8 - SRVCC

  • VoLTE Enhancements with Rel. 10 – eSRVCC

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

  • 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, ), QCI-Values and IP Transport Layer Mapping

  • IMS in the overall Network Architecture

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

  • And what is inside the IMS?

VoLTE Signaling – SIP and SDP

  • SIP and SDP

  • Scope of SIP

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

  • SIP Messaging between User Agents (UA’s)

  • 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

Other Private Headers for e.g. INVITE method, Example: SIP Logfile with Header and Routing Info

  • Important Header Extensions for VoLTE Applications

The “Contact:” Header Field

  • 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)), 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 (Public Service Identity (PSI), The Private Service Identity)

  • 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

  • VoLTE Specific Signaling Requirements

Reliable Provisional Responses and Supported Feature Indication (Indicating Support or Requirement of acknowledged provisional Responses), Reliability of Provisional Responses (The PRACK Method and SIP Headers RSeq and RAck)

  • Session Description Protocol

Part1: Session Description Items , Part 2: Time Description Items , Part 3: Media Description Items

  • Important Media and Session Details for VoLTE

The m-line Attribute (Media Type (MIME), Port-Number, Transport, Payload-Type-List, RTP Payload Type List, Media Transport Details, Example: AMR Codec definition), The Bandwidth Modifiers (CT (Conference Total), AS (Application Specific), TIAS (Transport Independent Application Specific), RR (Rtcp bandwidth for data Receiver) and RS (Rtcp bandwidth for data Sender))

  • The Offer / Answer Model

VoLTE Requirement: Precondition Framework, Example: SIP Logfile with SDP Parameter Definitions as Payload

VoLTE Operational Details

  • IMS Architecture Review

  • Generic SIP-Network Architecture

  • 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

  • I-CSCF – Tasks & Functions

  • Typical I-CSCF Use Cases

  • I-CSCF Involvement during UA Registration

  • Topology Hiding through the I-CSCF

  • S-CSCF – Tasks & Functions

  • Typical Use Cases of the S-CSCF

  • Registration Overview

  • Service Architecture and Routing

  • Routing Selection with Initial Filter Criteria

Example: Initial Filter Criteria and Trigger Point Configuration

  • SIP Routing Principles

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

  • Use Case of the BGCF

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

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

Other VoLTE related Protocols

  • Introduction to other important VoLTE-related Protocols

SIP Use within VoLTE, DIA (DIAMETER)), H.248 / MEGACO, RTP / SRTP (Real-time Transport Protocol / Secure Real-time Transport Protocol)

  • Introduction to the DIAMETER Protocol

  • IMS-specific Amendments to DIAMETER Protocol

  • Diameter Architecture Overview

  • 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, Example of Media Gateway Operation through H.248

  • DNS-Queries in the IMS-Environment

  • ENUM

  • 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))

Important Procedures and Scenarios

  • Attachment through E-UTRAN / new MME

  • VoLTE related Message Details

UE Capability Indication during Attachment Request

Network Capabilities and UE Configuration with ATT_ACC

Information Stored in EPS Entities after Attachment

LTE Connections and Bearers after Attachment

  • Detailed IMS Registration

3rd Party Registration

  • Detailed IMS Registration (continued)

  • Registration with SRVCC Enhancements (ATCF)

Example: SIP REGISTER – UE to P-CSCF (1st Register), , Example: SIP REGISTER – UE to P-CSCF (2nd Register), Example: SIP REGISTER – P-CSCF to ATCF, Example: SIP REGISTER – ATCF towards S-CSCF (Supported Feature Indications), Example: 200 OK Response (Register) – ATCF towards UE

  • Dedicated EPS Bearer Establishment

  • Session Establishment Signaling

Example: SIP INVITE – UE to P-CSCF, Example: SIP INVITE – P-CSCF to ATCF, Example: SIP INVITE – ATCF towards remote UA (via SCC-AS), Example: SIP 183 Session Progress Response – SCC-AS towards ATCF, Example: SIP 183 Session Progress Response – ATCF to P-CSCF

  • Network Initiated Bearer Establishment (IMS triggered)

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

VoLTE related Services

  • LTE and the Voice Alternatives


  • CSFB


  • VoLGA

  • Over The Top (OTT)

  • IMS

  • The Voice Evolution

  • Architecture in case of IMS-based Voice Services


  • IMS based VoLTE – A Brief Comparison

  • LTE Voice Architecture with IMS

  • LTE Voice Architecture with IMS (continued)

  • 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

  • Single Radio Voice Call Continuity (SRVCC)

  • SRVCC Evolution (eSRVCC, aSRVCC, rSRVCC, vSRVCC)

  • SRVCC in Release 8

Enhanced SRVCC (eSRVCC) – Rel. 10, , Example: SRVCC from eUTRAN to GERAN with PS Bearer HO (HO Preparation:, Bearer Splitting:, PS to CS Handover Initiation, Relocation of PS Bearers, Session Transfer Initiation, Handover Execution, Session Transfer Signaling, CS Handover Completion, Deletion of the old voice bearer, PS Handover Completion, Additional Emergency Services Handling)

  • VoLTE – The Service Overview and Summary

  • 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)