VoLTE and the IMS

In this course, you will learn about VoLTE, IMS, and the SIP protocol. This class thoroughly covers call flow through the EU-TRAN, the EPC, and into the IMS core. We will back up all that we teach with call flows and live labs using an IMS platform. This course also covers enough of other technologies like Diameter and DNS, providing you with a clear understanding of the complete picture. The lessons in this course are clear, very technical, and always practical, and since much of it is hands-on, you can investigate and reinforce the knowledge you've acquired from each lesson.

View Entire Schedule

IMS architecture
IMS and the DNS
IMS access using VoLTE
LTE E-UTRAN

Viewing outline for:

Classroom Live Outline

1. IMS Architecture and SIP Proxies

Components: HSS, Proxy-CSCF, Serving-CSCF, Interrogating-CSCF, and Policy Decision Function
IMS Identifiers
IMS Message Paths Introduction (Via and Record-Route)
The Service Path
Initial Filter Criteria Introduction

2. IMS Identifiers

IMSI
UICC
Home Network, Public ID, and Private ID
SIP URI Format

3. SIP Architecture

Requests and Responses
SIP Message Flow
SDP Introduction

4. SIP Via Paths

The Via: Header
Establishing the Response Path
Forking—Response Merging
Loops and Spirals
Max Forwards

5. SIP Route Headers

Route Path vs. Via Path
Record-Route and Route Headers
Establishing the Route Path
The Role of the S, I, and P Proxies

6. IMS Service Path

The Service Path
Path Header (RFC 3327)
Service-Route (RFC 3608)

7. DIAMETER

DIAMETER vs. RADIUS
AVPs
SCTP vs. TCP
IMS Command Values
IMS DIAMETER Example

8. Initial Filter Criteria

The User Profile
How the iFC Is Used
Understanding XML
Disjunctive and Conjunctive Normal Form

9. Basic SIP and IMS Specific Headers

Via, Branch, Max-Forwards
SIP Dialog (To, From, tag= fields, Call-ID:)
CSeq, Contact: Expires:
Proxy-Authenticate:, Proxy-Authorize:
User-Agent:, Allow:, Supported:
Content-Type:, Content-Length:
P-Access-Network-Info
P-Charging-Vector:, P-Preferred-Identity:, P-Asserted-Identity:, Authorization:
Security-Client:, Security-Server:
IMS Signaling Compression (SigComp Architecture)

10. Session Description Protocol (SDP)

Session Parameters
SDP Format
Extending SDP
SDPng
Media Negotiation
Changing Session Parameters

11. QoS, Real Time Media, and RTP

How Packet Loss, Jitter, and Latency Affects Voice
Making Voice and Data Coexist Efficiently
QoS Explained: What It Is and How It Works
QoS Criteria
QCI Table: 1-4 vs. 5-9
Dedicated Bearer When We Need to Change QoS
Dedicated Bearers
Dedicated Bearer Establishment
Sketch Network View of UE with Both Default and Dedicated Bearers
GBR or Non-GBR
MBR
Scheduling Resources for GBR Bearers vs. Not Scheduling for Non-GBR
Signaling for a Dedicated Bearer (E/W Diagram)
Channel Quality Indicator (CQI)
Mechanism for Sending Data to UE in Downlink
How Uplink Scheduling Differs from Downlink
Uplink and Downlink Operations to the Associated LTE Physical Channels
Uplink and Downlink Data Scheduled Every Subframe

12. Presence

SIMPLE: SIP for Instant Messaging and Presence Leveraging Extensions
Terminology
Framework
Resource List Manipulation Requirements
Authorization Policy Manipulation
Acceptance Policy Requirements
Notification Requirements
Content Requirements
General Requirements

13. Charging and New Services within the IMS

Charging Entities and Functions
P-Headers Related to Charging
Diameter and How It Is Used for Ro Interface

14. IMS Call Flow Examples

LTE Attach Based on an Actual Trace
Open-IMS Register
Open-IMS Invite
Open-IMS Chat Message
Open-IMS Instant Message
IMS SIP Register from an Actual Trace
IMS Invite from an Actual Trace

15. IMS and the DNS

DNS Basics
A-Record
The SRV Record (RFC2782)
How SIP Uses the SRV Record (RFC3263: Locating SIP Servers)
How to Configure a SRV Record
The NAPTR Record (RFC 2915)
How the P-CSCF Locates the I-CSCF
Introduction to ENUM (RFC 3761: ENUM Protocol)
How the S-CSCF Uses ENUM

16. SIP Timers

UDP and TCP Behavior
Session-Expires

17. IMS Access Using VoLTE

IMS Flow Using VoLTE
IMS Flow VoLTE to CS
User Plane and Control Plane

18. User Equipment and Radio Frequency

What Is User Equipment?
It Is All about Mobility!
New Requirements of 4G LTE
Control Signaling Overview (SIP, RCC, Diameter)
Information Encapsulation Methods: TLV, AVP, XML, ASN.1
Physical Layer Discussion
Types of Radio Signaling (History to LTE)
Types of Radio Architecture
Non Access Stratum Signaling
Signaling: OFDMA
SC-FDMA
2G / 3G Fallback to LTE

19. The LTE E-UTRAN

E-UTRAN
GSM/WCDMA View
CDMA View
Single Component: eNodeB Function and Purpose
Interfaces: Uu, X2, S1-MME, S1-U
Separation of Control Plane and User Plane
Introduction to Paging, Idle and Power Saving
Introduction to Tracking Areas

20. The UE Power Up Process

Frequency Scanning on Power-On
Steps after Power-On
Uplink Sync on PRACH Channel
System Information Blocks (SIBS and Types)
Channel Bandwidth, MIBs, and System Frame Number (SFN)
Cell Selection Steps
Random Access Response
RRC Connection Request
RRC Connection Setup
RRC Connection Setup Complete
RRC Idle State: Re-established and Released
UE Capability Enquiry from eNB and UE Capability Information Response
LTE Device Categories (1–5)
SIB 1 and SIB 2

21. The LTE Attach, GTP, APNs, and Default Bearers

Initial System Acquisition Steps
Key System Information Broadcast Messages
PRACH Channel
Synchronize with LTE Cell (Downlink and Uplink)
Request RRC Connection
Built in Features vs. Configured Features (IMSI, PLMN, Subscriber Info)
The Attach, GTP, APNs, and Default Bearer Assignment
Describe Network Attachment in LTE
Piggybacking Messages
Establishment of PDN Connectivity from LTE Air Interface
Attachment to MME: Manage Authentication and Security
Default Bearer (Connection to PDN)
SIP Signaling into the IMS

22. Downlink and Uplink Behavior

Downlink
Channel Quality Indicator (CQI)
Dynamic CQI Signaling and QAM
Reference Signal
CQI Report (PUCCH)
CQI Report and Data (PUSCH)
Periodic and Operator Defined CQI Reporting
CQI Index Table
PDCCH
DCIs
Uplink
Uplink Operation (UE to eNodeB)
Uplink Signaling
Scheduling Request on PUCCH
DL Control Information (DCI) on PDCCH
Buffer Status Report (BSR) on PUSCH
eNodeB Scheduler
UL Grand on PDCCH
Send Data on PUSCH

23. Idle Mode Within and Beyond the UE

Current Battery Technologies and How They Work
Saving the Battery and Operator Resources
Power Saving Features
Inactivity Timer
RRC_IDLE
EMM-REGISTERED
EMM-IDLE
Default Bearers Maintained in EPC During Idle
Contexts Removed in EU-TRAN During Idle
UE Context Release Request
UE Context Release Command
RRC Connection Release
UE Context Release Complete
State of EPC Bearers During Idle Mode with S-GW Buffering
Why Paging Is Necessary
Idle Mode "Always On" Activities (Cell Reselection, Tracking Area Update, Monitor for Paging, and Exit Idle Mode)

24. Tracking and Paging a UE

Why Tracking and Paging Is Necessary
Entities Involved in Tracking and Paging a UE
Tracking Areas (TAIs)
Tracking Area Update (TAU)
Paging to TAIs
TAU Keep Alive for UE
TAU Request, Authentication, EPC bearers, TAU response, TAU complete
T3450 Timer
GUTI
Paging Process from E-UTRAN
Bearer States During Idle Mode
S-GW Buffering During Idle Mode
RSRP
RRC_Idle
Service Request
Cell Reselection

25. Handover Between eNodeBs

The Need for UE Mobility and Cell Reselection
Cell Reselection Criteria
Home network Cell
PLMN Identity
"Barring" Status Check
Handover Between eNodeB
Identify Types of Handover in LTE
Measurements and Measurement Reporting (Event Driven vs. Periodic Driven)
Stages of Handover
Handover Coverage Areas
LTE Hard Handover: Serving Cells and Target Cells
RRC Connection Reconfiguration Message: Measurement Criteria (Absolute or Relative) and Measurement Reports
Handover Prep, Execution, and Completion
Handover Packet Buffering by SGW
Handover Data Forwarding Tunnel