Network Support Engineer - Ethernet & Optical

Colt Technology Services; Lisboa; On-site; EUR 55,000 - 75,000; Full time

Job summary

Colt Technology Services Group Ltd. in Lisbon, Madrid, and Barcelona seeks a Network Support Engineer to diagnose and resolve Ethernet and Optical faults across a European network. You will handle Layer 1/2 issues, coordinate with vendors and field teams, and provide clear updates to customers.

You'll join a 24/7 shift rotation, bring strong troubleshooting skills, and contribute to incident reports and network improvements. Fluency in English/B2 Spanish preferred.

Qualifications

• Hands-on experience troubleshooting Ethernet and/or Optical network services.
• Good working understanding of Layer 1 and Layer 2 networking.
• Structured fault finding with ability to investigate symptoms and causes.
• Experience with operational network services where availability matters.
• Confidently communicate technical info to customers and teams.
• Take responsibility for incidents and coordinate resolution.

Responsibilities

• Troubleshoot faults affecting Ethernet and Optical services across the network.
• Work across Layer 1 and Layer 2 technologies, with limited Layer 3 exposure.
• Follow issues from diagnosis through to resolution, involving specialists as needed.
• Keep customers informed with clear, actionable updates.
• Collaborate with network partners, Field Maintenance and technical teams to resolve incidents.
• Identify recurring problems and contribute to longer-term improvements.
• Support root-cause investigations and produce technical reports after significant incidents.
• Contribute to planned network changes and software upgrades.
• Work as part of a 24/7 shift rotation supporting Colt's network and customers.

Skills

Ethernet/Optical troubleshooting

Layer 1/Layer 2 networking

Incident ownership

Clear customer communication

Vendor coordination

Troubleshooting mindset

Job description

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Network Support Engineer - Ethernet & Optical

Job id: 36966

Job location: Lisbon, PT Madrid, ES Barcelona, ES

Why we need this role

Networks don't always behave as expected. When something goes wrong, our customers rely on Colt engineers to understand what is happening, find the cause and get their services back to where they need to be.

You’ll join our network operations environment, working across Ethernet and Optical services and tackling a varied range of technical issues. You’ll take ownership of incidents, collaborate with engineers, field teams, partners and technology vendors, and build your knowledge across a broad network environment.

If you already have a strong grounding in Ethernet or Optical networking, you don’t need to know every technology or vendor in our network from day one. We’re looking for solid troubleshooting skills, curiosity and the ability to learn.

What you will do

• Troubleshoot and resolve faults affecting Ethernet and Optical services across our European network.
• Work across Layer 1 and Layer 2 technologies, with exposure to Layer 3 services where relevant.
• Follow technical issues from initial diagnosis through to resolution, bringing in specialist teams or vendors when needed.
• Keep customers informed, translating complex technical issues into clear, useful updates.
• Work alongside network partners, Field Maintenance and technical teams to resolve service-affecting incidents.
• Look beyond the immediate fix by identifying recurring problems and contributing to longer-term improvements.
• Support root-cause investigations and produce clear technical reports following significant incidents.
• Contribute to planned technical activities, including network changes and software upgrades.
• Work as part of a 24/7 shift rotation supporting Colt's network and customers.

What we're looking for

You don't need experience of every technology in our network. We’re particularly interested in engineers who understand how networks work, enjoy troubleshooting and can apply that knowledge to unfamiliar problems.

Must haves

• Hands‑on experience troubleshooting Ethernet and/or Optical network services.
• A good working understanding of Layer 1 and Layer 2 networking.
• A structured approach to fault finding, with the ability to investigate symptoms and identify likely causes.
• Experience working with operational network services where resolving faults and maintaining availability are important.
• Confidence communicating technical information clearly with customers, engineering teams and other stakeholders.
• Ability to take responsibility for an incident and coordinate with others through to resolution.

Spanish and English at B2 level or above, with the ability to communicate confidently about technical issues with customers, partners and engineering teams.

• Ability to participate in a 24/7 shift rotation.

Might haves

• Knowledge of Optical transmission technologies such as WDM/DWDM, TDM, MSP, ADM or DCS/DXC.
• Understanding of IP networking and Layer 3 troubleshooting.
• Experience with equipment from Nokia, Ciena, Infinera, ADVA, Cisco, Juniper or similar network vendors.
• Familiarity with monitoring and network-management platforms such as Netcool, SMARTS, InfoVista, TACACS or vendor element managers.
• Experience working with NOCs, field engineering teams, carrier partners or equipment vendors.
• Experience supporting root‑cause analysis or producing technical incident reports.

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