Core CS/IMS Engineer

Key Responsibilities:

1-2G/3G: MSC, MGW, HLR, VLR, STP, GMSC, USSD Gateway

2-CS Fallback (CSFB) procedures in LTE

3-4G/5G IMS: P-CSCF, I-CSCF, S-CSCF, BGCF, MGCF, SBC, AS, HSS, ENUM, MRF

4-VoLTE/VoWiFi/ViLTE/VoNR call flows and service chains

5-Understanding of key network interfaces: A, Iu-CS, MAP, CAP, SIP, DIAMETER, ISC, Rx, Cx, Sh, Ut, Gm, Mw, Mg, etc.

6-Huawei: MSC/MSC-S, MGW, IMS, SBC (USN9810, UMG8900, IMS9000, etc.)

7-CS Core: MAP, ISUP, BICC, SIP-I, SCCP, CAP

8-IMS/VoLTE: SIP, SDP, RTP, DIAMETER (Cx, Sh, Rx), HTTP2 (for 5G IMS), DNS, ENUM

9-Wireshark, TShark, QXDM, TEMS, vendor-specific trace tools

10-Alarm monitoring and health check of CS/IMS nodes/KPI counters

11-Configuration management and service provisioning tools (SMP, PCRF interfaces, etc.)

12-Call setup failures (CS and IMS)/SRVCC, CSFB, VoLTE, VoWiFi issues/Codec negotiation, media path (RTP) issues