GPON Systems Developer

About the role

The GPON Systems Developer works with the Active Network and OSS teams to automate the management and monitoring of Vumatel's GPON access network. The role replaces manual, console-driven network operations with tested, repeatable software: automated configuration and provisioning against Huawei, Calix and Nokia OLT platforms, automated collection and interpretation of alarms, optical performance data and telemetry, and automated auditing of live network state against OSS inventory.

Responsibilities

• Automate network configuration and management:

  • Create and amend ONT service and line profiles, VLAN and traffic profiles, bandwidth profiles and port configuration across Huawei, Calix and Nokia OLT platforms.
  • Build and maintain the abstraction layer that presents a consistent internal interface over the three vendors' differing northbound interfaces and command syntaxes.
  • Implement automation against the appropriate interface for each platform, handling vendor-specific error responses, session limits, throttling and timeout behavior.
  • Develop and run automated bulk change campaigns, including batch processing, scheduling, progress reporting and per-device verification.
  • Maintain the credential and access model used by automation to reach network devices, ensuring secrets are held in a managed store, rotated, scoped to the minimum required privilege and excluded from logs.

• Automate network monitoring, assurance and fault finding:

  • Build and maintain collectors that ingest alarms, syslog, SNMP traps, telemetry and performance counters from the OLT estate, normalizing them across vendors into a common event model and publishing them to the platforms used by the NOC.
  • Develop alarm correlation, deduplication and suppression logic to reduce the number of individual ONT alarms raised for a single physical event.
  • Develop automated optical performance monitoring, rogue ONT, unauthorised device and PON instability detection, and the reporting that routes each finding to the correct team for action.
  • Design, review and evolve PostgreSQL schemas for network state, event history and performance data, including indexing strategy, partitioning of high-volume time-series and event tables, and archival or downsampling of historical records.
  • Write and tune SQL, verify queries against production-like data volumes in a lower environment before release, and build operational dashboards and scheduled reports used by the Active Network, NOC and Capacity teams.

• Deploy, infrastructure and scalability:

  • Containerize services using Docker and maintain their Kubernetes deployment configuration, including resource requests and limits, readiness and liveness probes, horizontal pod autoscaling and rolling update strategies that do not drop in-flight device sessions or lose collected events.
  • Perform load and soak testing ahead of significant releases or footprint growth, document the results, and adjust scaling, batching and polling configuration accordingly.
  • Monitor the automation and collection platforms themselves for exceptions and failed transactions, investigate the underlying fault, and drive each to resolution.

• Reliability, monitoring and incident response:

  • Build and maintain dashboards, metrics, structured logging and alert rules for every service the incumbent owns, ensuring each production failure mode produces an actionable alert routed to the correct responder.
  • Respond to production alerts within the agreed response times and lead technical triage where automation or monitoring failures affect network visibility or service delivery, including after hours.
  • Support the NOC and Active Network teams during major network incidents by extracting and interpreting device and event data at speed, and by building ad hoc queries or scripts needed to scope an outage.
  • Conduct and document post-incident reviews, produce written root cause analyses, and implement the resulting corrective actions to completion.
  • Write and keep current the runbooks, escalation paths and troubleshooting guides used by the NOC and by other engineers on call.

• Testing, quality and change control:

  • Write unit, integration and contract tests for all new and amended code, and maintain the vendor simulators, lab OLT environments and recorded device fixtures that allow automation to be tested without touching production equipment.
  • Validate every new automation in the lab against the relevant Huawei, Calix and Nokia platforms, and against each firmware version in production use, before it is permitted to run against the live network.
  • Review colleagues' pull requests, with attention to device safety, failure handling, backwards compatibility across vendor and firmware versions, observability and rollback safety.
  • Prepare and submit change records for production releases and for automated change campaigns, define and test the rollback plan for each, and execute changes during approved maintenance windows, which are frequently scheduled outside of business hours to protect customer-facing availability.

• Collaboration, documentation and knowledge sharing:

  • Work with the OSS Solutions Architect and Active Network engineers to refine automation designs, and produce interface specifications, sequence diagrams and architecture decision records.
  • Track vendor firmware releases, deprecations and northbound API changes, assess their impact on existing automation, and schedule the remediation work required.
  • Attend daily stand-ups, sprint planning, refinement and retrospective sessions, and provide realistic estimates and status on committed work.
  • Mentor junior and intermediate engineers through pairing, code review and structured handover of on-call and GPON domain knowledge.
  • Maintain accurate technical documentation in the team's knowledge base and record all work against the appropriate tickets in the team's tracking system.

Requirements

• At least five (5) years' experience in a comparable systems, software or network automation development role.
• Demonstrable hands-on experience with GPON access network technology, including OLT and ONT operation, service and line profiles, PON port and splitter architecture, ranging, and optical power levels and their interpretation.
• Working experience with Huawei, Calix and Nokia GPON platforms and their associated element and network management systems.
• Demonstrable experience automating configuration, provisioning or monitoring against live network equipment, including the safety and verification practices that make such automation acceptable in production.
• Experience designing for scale and resilience: retry and back-off strategies, idempotency, rate limiting, graceful degradation and recovery from partial failure.
• Technical skills: C#, the .NET ecosystem, PostgreSQL, network management protocols and interfaces, REST APIs, message queueing and asynchronous processing patterns, Elasticsearch, version control (Git), code review practice and CI/CD pipelines, automated testing across unit, integration and contract levels.
• Strong written communication in English, sufficient to produce runbooks, incident reports and interface specifications used by other teams.
• Willingness and ability to work in the Bryanston office on a full-time basis.
• Willingness to participate in a standby rota and to perform scheduled maintenance work outside of normal business hours.