Mobile Core Engineer – Remote

About the role

Telnyx is looking for a Mobile Core Engineer to join its Core Wireless Squad, an 11‑person team responsible for operating and enhancing Telnyx's wireless EPC infrastructure. This remote, hands‑on position focuses on troubleshooting subscriber connectivity issues, analyzing protocol traces, and ensuring the health of the mobile core across multiple data centres and roaming partners.

Key responsibilities

• Debug end‑to‑end attachment failures across S6a (Diameter), MAP (SS7), GTP‑C, and GTP‑U protocols.
• Decode and analyze pcap traces from DRA, STP, and GTP proxy capture points.
• Trace individual IMSIs across protocols and partner networks to locate session breaks.
• Diagnose DNN/APN routing mismatches, IMSI‑pinned APN gaps, and private wireless gateway configuration issues.
• Handle customer‑reported SIM connectivity problems from report to root‑cause resolution.
• Operate and troubleshoot EPC components such as HSS/HLR, DRAs, STPs, PGWs, SMFs, and GTP proxies.
• Maintain etcd‑based steering/blocking infrastructure and GTP proxy routing database.
• Coordinate with vendors and roaming partner NOCs to resolve platform and interconnect incidents.

Required profile

• Strong background in mobile core network operations and protocol‑level troubleshooting.
• Experience working with roaming partners, vendor management, and cross‑functional incident coordination.
• Ability to work independently in a remote environment while collaborating with a distributed team.

Required skills

• Diameter (S6a) and SS7 (MAP) protocol knowledge.
• GTP‑C and GTP‑U protocol expertise.
• PCAP analysis and trace decoding.
• FreeDiameter with custom Python transforms.
• Go programming for GTP proxy development.
• etcd for steering/blocking infrastructure.
• Operational experience with HSS, HLR, DRA, STP, PGW, SMF components.