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[LTE_203] VoLTE and IMS in LTE-EPC Networks

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The LTE Evolved Packet Core (EPC) is an evolution of the 3GPP system architecture with the vision of an all-IP network finally realized. EPC in conjunction with IP Multimedia Subsystem (IMS) delivers various services such as VoIP, SMS, Video call, Picture share, IM and Presence. EPC and IMS support mobility with the existing 2G/3G wireless networks as well as PSTN to facilitate smooth migration, interworking and service continuity across these networks. This course provides a detailed look at the architecture of the LTE EPC, IMS and QoS framework to deliver end-to-end voice (Voice over LTE – VoLTE) in LTE networks. It also covers various service scenario walk-throughs that utilize IMS and EPC network components. The IMS service architecture and the interaction with existing services are described.

Learning Objectives

After completing this course, the student will be able to:
• Sketch the EPC architecture and describe the role of various nodes in establishing a data session in LTE for IMS signaling
• Sketch the IMS network architecture and identify the role of key network nodes, interfaces, and related protocols
• List various protocols used in IMS networks to support VoIP
• Step through the IMS registration procedure
• Explain the role of the PCC network to deliver QoS
• Step through the interactions between LTE-EPC and IMS nodes to establish a VoIP call
• Step through the interworking of IMS with non-IMS networks such as PSTN
• Describe the IMS services architecture
• Discuss role of AS, RCS, MMTel, and ICS, and support for legacy services
• Sketch the charging architecture in LTE-EPC and IMS networks

Intended Audience

This course is designed for those involved in deployment and engineering of next generation wireless networks and services based on LTE-EPC and IMS.

Suggested Prerequisites

• [IPC_107] Overview of IMS (eLearning)
• [LTE_103] LTE SAE Evolved Packet Core (EPC) Overview (eLearning)

Course Length

3 days

Course Outlines / Knowledge Knuggets

1. LTE/EPC Network Essentials
1.1. LTE-EPC network architecture
1.2. Network nodes and roles of HSS, MME, S-GW, P-GW, and PCRF
1.3. Network interfaces and protocols

2. IMS Architecture
2.1. IMS network architecture
2.2. Role of CSCF, MGCF, MGW, HSS, AS
2.3. User addressing in IMS
2.4. End-to-end signaling and traffic flow

3. Protocols for VoIP and IMS
3.1. Diameter
3.2. SIP and SDP
3.3. H.248 (Megaco)
3.4. RTP and RTCP

4. VoLTE Pre-Call Functions
4.1. PDN connection for IMS APN
4.2. Default EPS bearer setup
4.3. IMS registration
4.4. IMS authentication

5. QoS Framework in LTE-EPC
5.1. QoS classes in LTE-EPC
5.2. PCC architecture
5.3. PCRF, PCEF, and AS
5.4. Interfaces: Gx, Rx
5.5. SDF, SDF aggregation, TFT

6. VoLTE Call Management
6.1. VoIP call setup in IMS
6.2. PCC interactions
6.3. SIP/SDP message details
6.4. Media format considerations
6.5. Emergency calls

7. Interworking in IMS
7.1. IMS – PSTN interworking
7.2. Roaming in IMS
7.3. Role of IPX

8. IMS Services Framework
8.1. Service architecture and role of AS
8.2. Telephony Application server (TAS)
8.3. Example supplementary services
8.4. Role of RCS and MMTel

9. SMS over IP Using IMS
9.1. SMS delivery architecture
9.2. SMS origination and termination
9.3. SMS interworking

10. IMS Charging Architecture
10.1. Overview of network nodes
10.2. Offline and online charging


- Self-paced, animated, and interactive

- $150/each course for 6 month license

- Immediate online access upon purchase

- Flexible way to take training at any hour

- Online training transcript available

- Electronic certificates at completion

- Full list of courses at


For any additional questions,
please contact Mr. Rod Marckese
at +1-972-664-0727 x246 or

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