SIM Management, 5G Core Engineer

Key Responsibilities

• As part of the 5G Core team, you will own the subscriber data management platform across our network generations. Your responsibilities include:

• Manage and operate UDR, and UDM nodes across 5G core domain, ensuring high availability and data integrity for subscriber profiles.

• Design and maintain subscriber provisioning workflows, including IMSI/MSISDN management, service profiles, and roaming configurations.

• Implement and verify HTTP/2-based (N8, Nudm) interfaces connecting subscriber data nodes to AMF and other core elements.

• Use and build dashboards to monitor subscriber node KPIs, quickly surface abnormal conditions, and identify patterns before they become outages.

• Own incident management for the subscriber data domain: follow communications procedures for internal escalation and external vendor coordination, ensuring SLAs are met.

• Perform maintenance, security audits, patching, and emergency response for UDM/UDR platforms.

• Undertake fault handling and corrective actions at node, service, and infrastructure level, including protocol trace analysis (Wireshark/tcpdump) on HTTP/2 signaling.

• Lead and contribute to project activities: E2E introduction of new subscriber management nodes, capacity expansions, software upgrades, and feature activations.

• Support onboarding by configuring subscriber data repositories, IMSI ranges, and roaming agreements in UDM/UDR systems.

• Collaborate with teams to resolve cross-domain subscriber authentication and registration issues.

Key Qualifications

At least 10 years of experience in core network engineering with a focus on subscriber data management in 5G Core networks.


Technical — Subscriber Data Management

• Deep operational knowledge of HSS/HLR or UDR/UDM platforms.

• Hands-on experience with configuration and troubleshooting.

• Practical experience with 5G UDM and UDR, including cloud-native deployments (containerized/Kubernetes-based NFs) and HTTP/2 SBI interfaces (N8, Nudm_SubscriberDataManagement, Nudr_DataRepository).

• Solid understanding of subscriber profile structures: 5GS subscription.

• Experience with IMSI/MSISDN range management, number portability (NP/MNP) integration, and SIM/eSIM provisioning workflows.
  

Technical — Network & Systems

• Working knowledge of 5G SA (AMF/SMF/UDM/UDR/AUSF/UDSF) core architectures and their subscriber data flows.

• Familiarity with 3GPP standards governing subscriber data: TS 29.503/29.504 (UDM/UDR SBI), TS 23.502 (5G procedures).

• Comfortable with Linux/Unix-based systems — able to navigate shells, interpret logs, manage processes, and perform basic system administration on telecom NF hosts.

• Hands-on with Wireshark, tcpdump, and vendor-specific trace tools for deep analysis of MAP, Diameter, and HTTP/2 subscriber signaling.

• Experience with high-availability configurations for subscriber databases: active/standby, geo-redundancy, and database replication/synchronization.

• Familiarity with cloud-native telecom platforms (Kubernetes) and Helm-based NF lifecycle management.

Education & Background

• Bachelor's or Master's degree in Telecommunications, Computer Science, or equivalent; post-graduate studies are a plus.

• 10+ years of core telecommunications network experience, with a minimum of 5 years hands-on with HLR, HSS, UDR, or UDM platforms.

Bonus Points for the Following

• Experience with 3GPP NTN core adaptations (Rel-17/18): satellite access node (SAN) architecture, timer and window parameter adaptation for high-latency links, or UPF placement in non-terrestrial topologies.

• Background in MVNO core architecture: roaming interfaces (N32/SEPP, Diameter S6a/S9), multi-PLMN federation, MVNO interconnect, or eSIM/SM-DP+ integration.

• Familiarity with 3GPP SA2/CT4 specifications or direct standards contribution experience.

• Experience with NEF or network exposure APIs and B2B API gateway architecture.

• Background in SIM provisioning platforms, subscription management, or UDM/HSS data modelling.

• Experience in a startup or fast-paced R&D environment where architectural decisions move at product speed.

Additional Requirements

This is a fast-paced, high-impact environment - flexibility to occasionally work extended hours or weekends during critical periods is expected.

This is a full time, exempt position, based out of our Santa Clara, CA office.

The total compensation packaged will be determined by various factors such as your relevant job-related knowledge, skills, and experience.

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