Ethernet & Optical Network Engineer

Colt Technology Services; Madrid; On-site; EUR 48,000 - 72,000; Full time

Job summary

Colt Technology Services in Spain seeks a Network Engineer to monitor and resolve faults on Colt's European Ethernet and Optical networks, owning incidents from diagnosis to resolution. You will work across Field Maintenance, partners and vendors, troubleshoot Layer 1/2/3 services, produce clear RCA reports, and participate in a 24/7 shift rotation to maintain service reliability.

Spanish and English at CEFR B2+ are required, with strong communication and hands-on carrier-network experience

Qualifications

• Troubleshooting Ethernet and/or Optical services in live networks.
• Strong understanding of Layer 1 and Layer 2 networking.
• Experience supporting carrier or service-provider networks.
• Ability to own incidents and coordinate across teams.
• Clear communication with customers and partners.
• Spanish and English at CEFR B2 level or above.
• Ability to work in a 24/7 shift rotation.

Responsibilities

• Monitor, diagnose and resolve faults across Colt's European Ethernet and Optical network.
• Troubleshoot Layer 1, Layer 2 and relevant Layer 3 services and identify root causes.
• Own customer incidents end to end with updates within service levels.
• Collaborate with Field Maintenance, technical teams, partners and vendors to resolve faults.
• Investigate recurring problems and contribute to reliability improvements.
• Produce RCA/RFO reports after significant incidents.
• Support planned network activities including software upgrades.
• Participate in the team's 24/7 shift rotation.

Skills

Troubleshooting Ethernet/Optical

Layer 1/2 networking

Incident ownership

Communication skills

Spanish/English B2+

24/7 shift readiness

Tools

Netcool

SMARTS

InfoVista

TACACS

Job description

Why we need this role

Colt's Ethernet and Optical networks support connectivity for customers across Europe. Keeping those services running reliably takes engineers who enjoy investigating technical problems and seeing them through to resolution. As a Network Engineer, you'll troubleshoot live Ethernet and Optical services, own customer incidents from diagnosis through to resolution, and work with Colt teams, partners and technology vendors to restore services quickly and effectively. You'll gain broad exposure to network technologies while developing deeper expertise across Ethernet and Optical infrastructure.

What you will do

• Monitor, diagnose and resolve faults across Colt's European Ethernet and Optical network.
• Troubleshoot Layer 1, Layer 2 and relevant Layer 3 services and identify the underlying cause of network and service issues.
• Own customer incidents end to end, providing clear updates and progressing resolution within agreed service levels.
• Work with Field Maintenance, technical teams, network partners and equipment vendors to resolve complex faults.
• Investigate recurring problems and contribute to solutions that improve network reliability and customer experience.
• Produce clear technical reports and root-cause analysis following significant incidents.
• Support planned network activities, including software upgrades and technical changes.
• Participate in the team's 24/7 shift rotation.

What we're looking for

Must haves

• Practical experience troubleshooting Ethernet and/or Optical services in a live network environment.
• Good understanding of Layer 1 and Layer 2 networking and a structured approach to fault diagnosis.
• Experience supporting carrier, service-provider or other large-scale network services.
• Ability to take ownership of technical incidents and work effectively with different teams to reach resolution.
• Clear communication skills, including the ability to explain technical issues to customers and partners.
• Spanish and English at B2 level or above (CEFR), with the ability to communicate effectively with customers and technical teams.
• Ability to work as part of a 24/7 shift rotation.

Might haves

• Knowledge of technologies such as WDM/DWDM, TDM, MSP, ADM, DCS/DXC or IP networking.
• Experience with network equipment from Nokia, Ciena, Infinera, ADVA, Cisco, Juniper or similar vendors.
• Familiarity with Netcool, SMARTS, InfoVista, TACACS or vendor-specific element management systems.
• Experience producing RCA/RFO reports.
• Experience working with global network providers, NOCs, field teams or technology vendors.