Offering a full suite of Layer 2 and Layer 3 switching capabilities as part of the base software, the EX 4200 series switches satisfy a variety of high-performance applications, including branch, campus and data center access deployments as well as Gigabit Ethernet (GbE) aggregation deployments. A single 24-port or 48-port switch can be deployed initially; as requirements grow, Juniper Virtual Chassis technology allows up to 10 EX 4200 series switches to be interconnected over a 128 Gigabit-per-second (Gbps) backplane and managed as a single device, delivering a scalable, pay-as-you-grow solution for expanding network environments. Flexible Gigabit Ethernet (GbE) and 10 Gigabit Ethernet (10GbE) uplink options enable high-speed connectivity to aggregation- or core-layer switches which connect multiple floors or buildings.

All EX 4200 series switches include HA features such as redundant, hot-swappable internal power supplies and field-replaceable, multi-blower fan trays to ensure maximum uptime. In addition, the base EX 4200 series switch models offer Class 3 power over Ethernet (PoE), delivering 15.4 watts on the first eight ports to support IP-enabled devices such as telephones, video cameras and wireless LAN (WLAN) access points for low-density converged networks. Full PoE options delivering 15.4 watts on all 24 or 48 ports are also available, making them ideal for high-density IP telephony deployments.

Each EX 4200 series switch includes an integrated application-specific integrated circuit (ASIC)-based packet-forwarding engine, the EX-PFE, while an integrated Route Engine (RE) delivers all control plane functionality. Based on field-proven Juniper technology, the Route Engine brings the same level of carrier-class performance and reliability to the EX 4200 series switches that Juniper routers bring to the world's largest service provider networks.