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Telnyx is building a private, global, multi-cloud IP network and edge connectivity platform. The Core Wireless Squad is an 11-person team responsible for operating and improving Telnyx's wireless EPC (Evolved Packet Core) infrastructure across multiple data centers with roaming partners and vendor platforms.
This is a hands-on operations role focused on deep protocol-level investigation and practical platform operations. You'll debug real subscriber issues, analyze pcap traces, coordinate with roaming partners and vendors, and keep the mobile core healthy.
Key responsibilities include:
**Subscriber & Connectivity Troubleshooting**: Investigate end-to-end attachment failures across S6a (Diameter), MAP (SS7), GTP-C, and GTP-U protocols. Decode pcap traces from DRA, STP, and GTP proxy capture points to isolate signaling failures. Trace individual IMSIs across protocols and partner networks. Diagnose DNN/APN routing mismatches and private wireless gateway configuration issues. Handle customer-reported SIM connectivity issues from initial report through root cause to fix.
**EPC Platform Operations**: Manage and troubleshoot HSS/HLR, DRAs (freeDiameter with custom Python transforms), STPs, PGWs, SMFs, and GTP proxies (Go). Work with etcd-based steering/blocking infrastructure. Operate the GTP proxy routing database. Participate in vendor management and escalation with platform vendors and roaming partner NOCs.
**Roaming & Interconnect**: Support sponsored roaming relationships and bilateral agreements. Investigate roaming registration failures and steering/blocking issues. Coordinate with partner NOCs on incidents including pcap exchange and joint root-cause analysis.
**On-Call & Incident Response**: Participate in weekly on-call rotation (1 week on, 10 weeks off). Respond to Opsgenie alerts for SMF overload, DRA peer down, HSS failures, GTP session rejects, and charging errors. Drive incident resolution end-to-end and write post-incident summaries.
**Automation & Tooling**: Use and extend pcap analysis tooling and protocol decoders. Contribute configuration and automation for EPC infrastructure (Ansible, Kubernetes). Improve observability through Grafana dashboards, alerting rules, and protocol-level metrics. Make small code changes when needed, though this is primarily an operations role.
Required: 3+ years operating or engineering telecom infrastructure (EPC, HSS/HLR, DRA, STP, PGW, SMF, or equivalent). Strong understanding of mobile core protocols and willingness to learn vendor-specific platforms.
