Delegates should have attended LTE Engineering Overview (LT3600) or have equivalent knowledge. A working knowledge of IP would also be beneficial.


Course Contents
Section 1 Introduction to LTE
Section 2 SIP Architecture and Operations
Section 3 IMS Architecture and Network Elements
Section 4 VoLTE
Section 5 VoLTE Service Centralization and Continuity
Section 6 Additional VoLTE Services

Section 1
Introduction to LTE

  • LTE - The Long Term Evolution of Mobile Broadband
  • 3GPP Evolution
  • Evolved UMTS Terrestrial Radio Access Network (E-UTRAN)
  • Evolved Packet Core (EPC)
  • Evolved Packet Core 'S' Interfaces
  • End-to-End Connectivity
  • EPS Interoperation With Gn/GP Based SGSNs - Non Roaming Case
  • EPS Interoperation with Gn/GP based SGSNs - Roaming
  • Packet Data Network (PDN) Connectivity Services
  • Default and Dedicated EPS Bearers
  • EPS Quality of Service (QoS)
  • QoS Class Identifier (QCI)
  • Allocation and Retention Priority (ARP)
  • Interface to CS Networks
  • LTE Voice Options
  • LTE Voice - CS Fallback
  • LTE Voice - VoLTE

Section 2
SIP Architecture and Operation

  • What is SIP (Session Initiation Protocol)?
  • SIP User location and Session Control Basic Concepts
  • Challenges in SIP Peer-to-Peer Operation
  • SIP a Request/Response Protocol
  • SIP Session Establishment (Peer-to-Peer Operation)
  • User Agents Clients/Servers, Dialogues and Transactions
  • SIP Architecture
  • Five Facets of SIP
  • SIP URIs and Tel URIs
  • SIP Message Structure
  • User Location - Registration Procedure
  • Cancelling Registration
  • SIP Authentication and Authorization
  • The Authentication Concept
  • WWW-Authenticate and Authorization Headers
  • Proxy-Authenticate and Proxy-Authorisation Headers
  • Session Establishment Using a SIP Architecture
  • SIP INVITE Message
  • Caller Preferences
  • SDP (Session Description Protocol)
  • RTP/AVP Audio and Video Payload Types
  • SDP Attribute Values
  • SIP Routing - Request and Response Routing
  • Record-Route and Route Headers
  • SIP Methods
  • Response Codes
  • SIP Proxy Servers
  • B2BUA (Back-to-Back User Agent)
  • Forking Proxy
  • Forking Proxy Signalling Example
  • SDP Offer/Answer Model
  • Other SDP Offer/Answer Techniques
  • SIP Operation in Proxy Mode
  • SIP Operation in Redirect Mode
  • Attended Call Transfer
  • Conference Server
  • The SIP Call Model
  • SIP to PSTN Interworking
  • Q.1912.5 Profiles A and B
  • Q.1912.5 Profile C - SIP-I
  • MIME and Encapsulated ISUP Support
  • Profile B Call Example
  • En-bloc Dialling with Early Media
  • Overlap Dialling
  • SDP Message
  • Connection Information
  • Media Information
  • SIP Response Status Codes - Informational Responses 1xx
  • SIP Response Status Codes - Redirection Responses 3xx
  • SIP Response Status Codes - Request Failure Responses 4xx
  • SIP Response Status Codes - Server Failure 5xx
  • Global Failures 6xx
  • SIP Warning Code List

IMS Architecture and Network Elements

  • The Role of the IMS
  • Introduction to the IMS Architecture
  • CSCFs (Call Session Control Functions)
  • P-CSCF (Proxy CSCF)
  • I-CSCF (Interrogating CSCF)
  • S-CSCF (Serving CSCF)
  • SIP Signalling and User Data Flow Paths
  • Access Technologies - the Access-Agnostic Approach
  • GPRS Access to the IMS
  • IMS Access via LTE/EPS
  • WLAN Access
  • DSL Access to the IMS - Generalized TISPAN Architecture
  • IMS CS Interworking Functions
  • Media Resource Function
  • Interconnect Border Control Function and Transition Gateway
  • Roles and Responsibilities of the HSS
  • Evolution to the HSS and HSS Interface Support
  • SLF (Subscriber Locator Function)
  • Identities
  • The UICC (Universal Integrated Circuit Card)
  • SIP Forking in IMS
  • User Profile in the HSS
  • Core Network Service Authorization
  • The IMS Service Architecture
  • Service Interaction with ASs
  • iFC (Initial Filter Criteria)
  • SPT (Service Point Trigger)
  • S-CSCF Handling Registration
  • Filter Criteria Triggering
  • Session Handling for SIP Application Servers
  • Mobile-Terminated Session
  • CF (Call Forwarding) through Application Servers
  • Call Forwarding - Redirect Mode
  • Call Forwarding - Proxy Mode
  • RADIUS and Diameter
  • Diameter as a Peer-to-Peer Protocol
  • Diameter Application Commands and Application Interworking
  • Diameter on the IMS Cx - I-CSCF
  • Diameter on the Cx-Interface - S-CSCF
  • Diameter on the Dx-Interface
  • Diameter on the IMS Sh Interface
  • Diameter on the Dh-Interface
  • Mapping of Diameter Command Codes to Cx operations
  • HSS Interaction with Application Servers
  • Summary - IMS Functional Elements
  • Summary - IMS Interfaces
  • Summary - Key IMS Functions
  • Summary - CSCF Functions
  • Summary - HSS Functions
  • Summary - Support Functions
  • Summary - Service Functions and Legacy CS Functions
  • Summary - IMS Security and Charging Functions
  • Summary - Key IMS Functions

Section 4

  • VoLTE General Concept
  • One Voice Initiative
  • GSM Association (GSMA) VoLTE
  • Key VoLTE Recommendations
  • Architecture and Interfaces
  • IMS-EPC Interface Elements
  • Roaming Architecture
  • VoLTE APNs
  • UE Connections
  • VoLTE EPS Bearers
  • VoLTE Security
  • The Role of SIP, SDP and RTP in the IMS
  • SIP - a Request/Response Protocol
  • Session Description Protocol (SDP)
  • Multimedia Telephony (MMTel)
  • MMTel Components
  • XML Configuration Access Protocol (XCAP)
  • Supported Codecs
  • Example Packet Sizes in the Fixed Network
  • Radio Requirements
  • Protocol Stack Efficiency
  • Example Packet Sizes in the Air Interface
  • AMR Mode Selection
  • Radio Resource Allocation
  • Measurements of VoIP Speech Quality using RTCP XR (Extended Reports)
  • UE VoLTE Configuration for IMS
  • User Identities for IMS
  • UE and Subscription Dependencies
  • IMS/SIP Registration
  • VoLTE Power-On Procedures
  • EPS Initial Attach
  • PDN Connectivity Request to IMS APN
  • REGISTER Message
  • SIP Registration and IMS Authentication
  • Third Party Registration with Application Servers (ASs)
  • Subscription to the Registration State Event Package
  • Basic Requirements for GSMA IR.92 Media Sessions
  • INVITE Message Example
  • SIP Operation in IMS
  • IMS Mobile-Originated to IMS Mobile-Terminated Session
  • Interactions with PCRF
  • Dedicated EPS Bearer Establishment
  • Inter-IMS Network-to-Network Interface (II-NNI) and Optimal Media Routing (OMR)
  • Voice over IMS with Home Routed Traffic
  • Voice over IMS with VPLMN Loopback and Local Breakout
  • Call Origination with VPLMN Loopback and Local Breakout
  • Tel: URIs and the E.164 Number Mapping (ENUM) Database
  • Tel: URIs and the BGCF
  • Tel: URIs and Local Breakout (1)
  • Tel: URIs and Local Breakout (2)
  • IMS Mobile-Originated Session to PSTN or Legacy Destination
  • PSTN or Legacy-Network-Originated to IMS Mobile-Terminated Session
  • Session Clearing
  • Error Handling - Examples
  • VoLTE Charging
  • Benefits and Disadvantages

Section 5
VoLTE Service Centralization and Continuity

  • LTE Voice Options Comparison
  • EPS and CS Fallback
  • EPS and VoLTE
  • Coexistence
  • Procedures for CS Only
  • Procedures for IMS Preferred - UE Initiates Attach
  • Procedures for IMS Preferred - UE Initiates Combined EPS/IMSI Attached
  • Homogeneous and Inhomogeneous Support of IMS Voice
  • Routing Area Update (RAU) Procedure
  • Domain Selection
  • Service Centralization and Continuity Application Server (SCC AS)
  • MT Calls Directed to the IMS
  • MT Calls directed to the IMS - IMS Service, PS Access
  • MT Calls Directed to the IMS - IMS Service, CS Access
  • MT Calls Directed to the CS Domain
  • MT Calls Directed to the CS Domain - IMS Service, PS Access
  • MO Calls
  • MO Calls - CS Access, IMS Service
  • Handover Options and SRVCC
  • PS Handover
  • E-UTRAN to UTRAN PS Domain HO
  • SRVCC Features
  • EPS Dependencies for SRVCC
  • Legacy Core Network Dependencies
  • SRVCC Configuration
  • SRVCC Generalized Procedure
  • SRVCC Session Transfer
  • E-UTRAN to UTRAN with PS HO Support or GERAN with DTM HO Support
  • E-UTRAN to GERAN without DTM Support
  • Enhanced SRVCC Configuration
  • Enhanced SRVCC PS to CS Handover Procedure - Generalized UTRAN Example
  • Return to E-UTRAN
  • IMS Centralized Services Architecture
  • Registration over the I2 Interface
  • MO Calls over the I2 Interface
  • SRVCC Access Transfer (Incoming Call in Alerting Phase)
  • SRVCC Access Transfer (Outgoing Call in Pre-Alerting or Alerting Phase)
  • Reverse SRVCC Architecture
  • Registration for Reverse SRVCC
  • CS Call Setup for Reverse SRVCC (1)
  • CS Call Setup for Reverse SRVCC (2)
  • CS to PS Handover from UTRAN (1)
  • CS to PS Handover from UTRAN (2)
  • CS to PS Handover from UTRAN (3)

Section 6
Additional VoLTE Services

  • SMS Over IP
  • SMS Over IP Registration/Deregistration
  • SMS Over IP Sender and Receiver Procedures
  • Access Domain Selection (ADS) for SMS
  • Supplementary Services
  • Originating Identification Restriction (OIR)
  • Originating Identification Presentation (OIP)
  • Communication Forwarding on No Reply (1) - No reply
  • Communication Forwarding on No Reply (2) - Communication Forwarding
  • Emergency Call Requirements
  • Emergency Call Architecture
  • Access Domain Selection for Emergency Calls
  • Emergency Call set-up - Overview
  • Emergency Call set-up - PDN Connectivity Request
  • Emergency Call set-up - SIP REGISTER procedure
  • Emergency Call set-up - SIP INVITE Procedure (1)
  • Emergency Call set-up - SIP INVITE Procedure (2)
  • Emergency Calls and SRVCC Operation
  • Emergency Calls and PSAP Callback
  • Emergency Calls in a Limited Service State
  • Key Features of Voice over Wi-Fi (VoWi-Fi)
  • Non-Roaming Architecture for VoWi-Fi
  • Roaming Architecture for VoWi-Fi
  • Access Network Discovery and Selection Function (ANDSF)
  • User Plane Protocol Stack
  • Wi-Fi Attach Procedure (1)
  • Wi-Fi Attach Procedure (2)
  • PDN Connectivity Request to IMS APN
  • VoWi-Fi Call Setup
  • Handovers from LTE to Wi-Fi
  • Dual Radio Voice Call Continuity (DRVCC)
  • DRVCC from Wi-Fi to 2G/3G
  • Reverse DRVCC (rDRVCC) from 2G/3G to Wi-Fi
  • Video Telephony Service
  • Video Bearers
  • SIP Signalling for Video
  • Example SDP Offer for Video
  • Example Bandwidth Calculations for H.264
  • Rich Communication Services (RCS)
  • RCS Services and Access Technologies

3 Days


This is a QA approved partner course

Delivery Method

Delivery method


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