Transport Network Engineer III

Our customer, the Defense Information Systems Agency (DISA-GLOBAL) at Scott AFB, il provides, operates, and assures command and control of the Defense Information System Network (DISN) services to its customers, the department of Defense (DoD) and national security organizations. This position directly supports the DISA-provided capabilities and services. The Leidos Digital Modernization Sector/Global Solutions Management-Operations II (GSMO-II) contract has an opening for a Transport Network Engineer. The Transport Network Engineer will perform sustainment, maintenance, Problem and Change management services to help ensure secure, reliable, and uninterrupted availability of the Department of Defense networks. Responsible for performing the following duties: Network design and engineering • Perform network management system design, develop Methods of Procedure, analysis, testing and/or modifications of architecture in support of software/hardware technical refresh and upgrades approved by the Engineering Review Board. • Implement new network hardware (shelves, cards) on operational nodes. • Deploy network changes - monitor for any impacts to customer traffic using provided expectations of traffic behavior, lessons learned, and customer reporting. • Recommend to manager best practices for the operation and maintenance of the network. • Provide ad-hoc engineering support, statistics/data gathering, modeling, creating/updating flowcharts and providing recommendations to determine the most efficient configuration of the network based on Engineering documents and experience. Provide Engineering Incident Management Escalation Support • Perform fault isolation, analysis, and troubleshooting across various Transport platforms including SONET Optical/Fiber Transport (ODXC/MSPP), Dense Wavelength Division Multiplexing (DWDM), Time Division Multiplexing (TDM), and cryptographic systems. Engage with other Engineers (Transport, IP and Unified Capabilities), vendors, and customers to determine Root Cause Analysis • Update ServiceNow tickets with accurate documentation • Provide situational awareness reporting to customer and management. • Provide accuracy in documenting the Mission Support Services (MSS) database to reflect the real time network. • Support Authorized Service Interruption (ASI) Activities to collect site and device data to schedule maintenance windows, coordinating dispatch of technicians, and identifying availability of site personnel. • Interact with Problem Coordinator and Government customer for troubleshooting and resolution of Problem Management candidate tickets. • Interact with vendor Technical Assistance Center (TAC) personnel to gather needed data to create hardware replacement order. Basic Qualifications: • Currently possess an active Secret security clearance. • Currently possess DoD 8750 certification at IAT level II, Security+ CE or equivalent to meet requirement. • Proficient in one or more Transport platforms: CIENA 6500, CIENA Corestream, Cisco NCS2K, CISCO MSPP 15454/15310, SYCAMORE ODXC 16K/9K, XTERA, and other ancillary equipment. • Experience analyzing section, line, and path events on Optical networks • Experience with end-to-end system loopback testing and troubleshooting on Transport networks. • Exposure to troubleshooting, assessment, root cause analysis, and restoration of Optical networks. • Experience working with service providers and/or enterprise Transport systems utilizing CISCO/CIENA devices. • Experience with ports and protocols for DWDM and SONET technologies. Preferred Qualifications: • Equally proficient in Ciena and/or Cisco configuration, and troubleshooting, and design • Experience with Power systems and Network Timing • Experience with Dense Wavelength Division (DWDM) and Synchronous Optical Networks (SONET) • Possess understanding of Physical (Layer 1) and Data Link (Layer 2) network troubleshooting. • CIENA 6500 configuration, troubleshooting, and design experience. • CISCO 4200 configuration, troubleshooting, and design experience • CISCO NCS2K configuration, troubleshooting, and design experience. • Crypto configuration, troubleshooting and design experience. • Physical cable plant and wiring experience. • Excellent project, technical, interpersonal, presentation and problem management skills. • Extensive network integration experience for a variety of network protocol standards. • Ability to communicate orally, and in writing, detailed technical information on troubleshooting and implementation efforts. • Familiarization of DOD regulations and directives. Required Education and Experience: Requires BS degree and 4-8 years of prior relevant experience or Masters with 2-6 years of prior relevant experience. (Or equivalent combination of education and/or experience.) GSMO If you're looking for comfort, keep scrolling. At Leidos, we outthink, outbuild, and outpace the status quo — because the mission demands it. We're not hiring followers. We're recruiting the ones who disrupt, provoke, and refuse to fail. Step 10 is ancient history. We're already at step 30 — and moving faster than anyone else dares. Original Posting: August 17, 2026 For U.S. Positions: While subject to change based on business needs, Leidos reasonably anticipates that this job requisition will remain open for at least 3 days with an anticipated close date of no earlier than 3 days after the original posting date as listed above. Pay Range: Pay Range $73,450.00 - $132,775.00 The Leidos pay range for this job level is a general guideline only and not a guarantee of compensation or salary. Additional factors considered in extending an offer include (but are not limited to) responsibilities of the job, education, experience, knowledge, skills, and abilities, as well as internal equity, alignment with market data, applicable bargaining agreement (if any), or other law.