SEAPORT NXG MAC HOLDERS ONLY and Small Business Set-Aside ONLY, In-Service Engineering Activity (ISEA) Navy Enterprise Networks (NEN) Description which includes the four (4) core Capability-Based (CB)... SEAPORT NXG MAC HOLDERS ONLY and Small Business Set-Aside ONLY, In-Service Engineering Activity (ISEA) Navy Enterprise Networks (NEN) Description which includes the four (4) core Capability-Based (CB) ISEA services: Technical Sustainment Support (TSS), Sustainment Engineering Support, Logistics Support, and Modernization Support. See SOW for details.