Here is a comprehensive Q&A for VoLTE in IMS to help you in your next IMS interview or refresh your IMS knowledge.
Test Objectives:
- A. Understanding VoLTE (Voice over LTE)
- B. VoLTE Benefits
- C. VoLTE Requirements and Evolution
- D. Understand the concept and benefits of VoLTE
- E. Break down the architectural components of a VoLTE network
- F. Learn about the process of migrating an existing 4G network to support VoLTE, including necessary upgrades and configurations
- G. Understand the concept of EPS Bearers and their role in VoLTE
- H. Explain the signaling flow for VoLTE UE Attach and Default Internet EPS Bearer setup.
- I. Describe the call flow for IMS APN Connectivity and Default IMS EPS Bearer activation.
- J. Understand the detailed SIP signaling flow for IMS Registration in VoLTE, including the initial registration attempt and successful registration
- K. Explain the purpose and process of TAS (Telephony Application Server) Registration in VoLTE
- L. Understand the high-level steps involved in a VoLTE call
- M. Describe the SIP message exchange during a VoLTE call setup
- N. Explain the codec negotiation process in VoLTE and the commonly used codecs.
- O. Understanding the concept of SRVCC and its relevance in mobile networks.
- P. Detailing the SRVCC call flow and its two main phases.
- Q. Understanding the advanced concepts of SRVCC, including SRVCC Identities, network changes for SRVCC enablement, and the evolution of SRVCC (eSRVCC & aSRVCC).
- R. Understanding the concept and significance of KPIs in a VoLTE IMS Network.
- S. In-depth knowledge of key VoLTE Control Plane KPIs like RSR, CSSR, CST, and MHT/ACD, along with their calculation, impact, and troubleshooting.
- T. Understanding VoLTE User Plane KPIs such as MOS, Mute Rate, RTP Packet Loss, and One-Way Calls, their impact on user experience, and how to interpret their values.
- U. Knowledge of Packet Core KPIs like VoLTE Attach Success Rate, VoLTE Paging Success Rate, Dedicated Bearer Activation Success Rate, and IMS IP Pool Utilization, and their importance in VoLTE service delivery.
- V. Understanding crucial Radio KPIs such as VoLTE Call Drop Rate, SRVCC Success Rate, and Handover Success Rate, and their role in a stable and high-performing VoLTE IMS Network.
- W. Understand the limitations of 4G networks related to voice and telephony services and how those limitations were addressed before the implementation of VoLTE.
- X. Grasp the technical details of SMS delivery in the context of 2G/3G, 4G (non-VoLTE), and VoLTE networks.
- Y. Explore how telecom operators can leverage existing CS Core Network infrastructure during and after VoLTE deployment.
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