L3 Network Support Engineer

ST ENGINEERING INFO-SECURITY PTE. LTD.; Singapore; On-site; SGD 120,000 - 180,000; Full time

Job summary

ST ENGINEERING INFO-SECURITY PTE. LTD. is seeking a Tier 3 Principal Engineer to join the Competency Specialist Office.

The role focuses on advanced technical support, troubleshooting complex network issues, and maintaining enterprise network infrastructure for customers. The incumbent will also design and deliver technical training, mentor Tier 1/2 engineers, and develop knowledge base materials. The ideal candidate will have strong expertise across enterprise networking, security, wireless,

Qualifications

• Strong hands-on experience with enterprise networking and security technologies.
• Experience in fault isolation, root-cause analysis and incident management.
• Experience in designing and delivering technical training for Tier 1/2 engineers.
• Ability to document SOPs, KB articles, and technical guides.
• Experience working with customers, vendors and SI/Managed Services environments.

Responsibilities

• Provide Tier 3 technical support for customers' enterprise network infrastructure.
• Act as final escalation for complex incidents beyond Tier 1/2.
• Perform advanced troubleshooting, root cause analysis and incident resolution.
• Collaborate with Customer Success Managers to meet service deliverables.
• Develop training materials and mentor junior engineers.

Skills

Enterprise networking

Networking troubleshooting

Technical training

Mentoring

Vendor escalation

Documentation writing

Communication skills

Tools

Cisco switches

Cisco routers

Cisco Nexus

SolarWinds

Aruba ClearPass

Job description

Role Summary

We are seeking a highly motivated and experienced Tier 3 Principal Engineer to join the Competency Specialist Office. The successful candidate will be responsible for providing advanced technical support, troubleshooting complex network issues, and maintaining enterprise network infrastructure for our customers. This role serves as the highest level of technical escalation within the operations team and works closely with customers, internal stakeholders, and technology partners to ensure high service availability and operational excellence.

In addition to technical support responsibilities, the Tier 3 Principal Engineer will play a key role in developing the technical capabilities of the engineering team by designing and delivering technical training, mentoring Tier 1 and Tier 2 engineers, developing knowledge base articles and technical documentation, and promoting best practices to enhance overall team competency and service quality.

The ideal candidate must possess strong technical expertise across enterprise networking, security, wireless, and data centre technologies, with proven experience in problem diagnosis, root cause analysis, vendor escalation, solution implementation, and technical knowledge transfer.

Key Responsibilities

Technical Support & Operations

• Provide Tier 3 technical support for customers' enterprise network infrastructure.
• Act as the final technical escalation point for complex incidents beyond Tier 1 and Tier 2 support.
• Perform advanced troubleshooting, fault isolation, patching and root cause analysis to restore services within agreed service levels.
• Work closely with engineers and customers to resolve technical issues and provide timely updates.
• Open, manage, and drive TAC cases with principal vendors until successful resolution.
• Coordinate with vendors during critical incidents and product defects.
• Collaborate with Customer Success Managers to meet contractual service deliverables and operational requirements.

Training & Technical Development

• Plan, develop, and deliver technical training sessions for Tier 1 and Tier 2 engineers to enhance their technical competency.
• Design and maintain structured training materials, laboratory exercises, and hands‑on workshops covering enterprise networking and security technologies. Develop and execute test plans for new software releases, patches, and hardware platforms.
• Assess engineers' technical proficiency and recommend development plans to address knowledge gaps.
• Develop and maintain technical documentation, standard operating procedures (SOPs), knowledge base (KB) articles, troubleshooting guides, and best practices.
• Keep the engineering team informed of operational best practices through the training sessions.

Technical Competencies

Support and troubleshoot technologies including, but not limited to:

Routing & Switching

• • Cisco Catalyst Switches, Cisco Nexus Switches, Cisco Routers
  • Alcatel OmniSwitch

Wireless Networking

• • Cisco Wireless LAN Controllers and Access Points, Alcatel Wireless and Aruba Wireless

Network Security

• • Cisco FTD, Cisco ASA, Cisco ISE, Cisco IPS/IDS, Cisco ESA, Cisco WSA, Cisco SMA
  • Fortinet Firewalls, Check Point Firewalls, Palo Alto Firewalls
  • Aruba ClearPass

Network Monitoring

• • SolarWinds NPM, SolarWinds NCM, SolarWinds NTA

Cloud Networking (Hybrid / Cloud-Enabled Infrastructure)

• • Basic understanding of cloud networking concepts in AWS, Microsoft Azure, or Google Cloud
  • Understanding of VPC/VNet concepts, subnets, routing, and security groups (conceptual level)
  • Awareness of hybrid connectivity (VPN, Direct Connect / ExpressRoute concepts)
  • Willingness and ability to develop cloud networking skills as part of future infrastructure evolution

Requirements

• Cisco certifications are preferred.
• Good communication and writing skills.
• Self‑motivated and able to work independently.
• Minimum5 yearsof hands‑on enterprise network support experience, with at least3 years in a Tier 3 or senior network engineering role
• Strong experience supporting LAN, WAN, WLAN, Data Center, and Network Security technologies.
• Proven experience in implementation, maintenance, troubleshooting, and break‑fix activities.
• Basic knowledge of cloud networking concepts and platforms (e.g., AWS, Microsoft Azure, or Google Cloud) is preferred. Candidates with strong interest in cloud technologies and a willingness to learn will be considered.
• Experience supporting mission‑critical production environments.
• Experience working in a System Integrator (SI), Managed Services, or Enterprise IT environment.
• Able to respond to critical incidents within defined SLA timelines.
• Willing to participate in rotating 24×7 standby/on‑call support roster.
• Able to perform after‑hours maintenance activities when required.
• Willing to work at customer sites as required

Work location: Jurong East