Routing/traffic engineering (BGP, OSPF/ISIS), path control, convergence, SD-WAN and secure connectivity (SASE/SSE), segmentation/policy design, QoS (marking/queuing/shaping), performance engineering, capacity planning. Support the SAIC Chief Engineer with MOPs, implementation plans, cutover schedules, rollback procedures, and test/validation plans; participate in technical reviews and change control; identify/mitigate risks per work package.