The 3940 features a high-capacity switching fabric with 24 Gigabit Ethernet (GbE) ports in a compact single rack unit (1RU) form factor, allowing front access to all data and management interfaces. This efficient packaging design provides both SFP and RJ-45 connectors for each of the 24 user ports, enabling deployment of the 3940 for service demarcation, aggregation, and transport applications in a wide variety of physical environments and network topologies, including fiber and microwave rings, point-to-point fiber, microwave mesh, and fiber or copper to subscriber.

The 3940 is based on Ciena’s field proven True Carrier Ethernet^® technology, deployed by dozens of network operators in tens of thousands of homes, businesses, and mobile base station cell sites. The switch combines the low cost and high capacity of Ethernet with the reliability, management, and service quality usually associated with SONET/SDH networking systems. The 3940 software architecture is based on the common service-aware operating system used in all Ciena service delivery and aggregation switches to provide operational efficiency and consistent system and service attributes.

The core of the 3940 is a high-performance switching platform that incorporates the latest innovations in Ethernet switching technology, control plane protocols, and encapsulation techniques, and Carrier Ethernet Operations, Administration, and Maintenance (OAM) mechanisms.