Juniper's EX switches cover the wiring closet and the server row. This guide sets four of them side by side: the EX3400 and EX4400 at the gigabit edge, the EX4550 for 10GbE, and the EX4650 for 25GbE servers with 100GbE uplinks. It also covers the uplink modules, rack kits and JPSU power supplies they take. Every figure comes from Juniper's datasheets, hardware specifications and end of life pages, listed under Sources.
The short answer
Pick by the port speed. The EX3400 and EX4400 are the access closet switches; the EX4400-48F gives more than twice the switching capacity of the EX3400-48T and stacks over a faster interconnect. The EX4550 is a 10GbE switch with 32 ports on the base unit and slots for expansion modules, and Juniper stopped selling it in 2019. The EX4650-48Y is the one for 25GbE servers, with 48 25GbE ports, 8 100GbE uplinks and latency as low as 550 nanoseconds.
The models side by side
| Model | Ports | Switching capacity | Stacking | Power |
|---|---|---|---|---|
| EX3400-48T | 48 x 10/100/1000BASE-T, 4 x 1/10GbE SFP/SFP+, 2 x 40GbE QSFP+ | 168/336 Gbps | Up to 10, 160 Gbps over QSFP+ | 150 W AC |
| EX4400-48F | Extension slot for the EX4400-EM-4S (4 x 1/10GbE SFP+) | 456/912 Gbps, 678 Mpps | Up to 10, 400 Gbps | 2 supplies, 1+1 |
| EX4550-32F | 32 x 1/10GbE SFP+, expansion slots | Not stated | EX4550-VC1-128G module, 128 Gbps | 650 W AC or DC |
| EX4650-48Y | 48 x 25/10/1GbE, 8 x 100/40GbE | 2/4 Tbps, 2976 Mpps | Not stated | 2 x 650 W DC on the DC model |
EX3400 and EX4400: the access closet
The EX3400-48T has 48 10/100/1000BASE-T ports, 4 1/10GbE SFP/SFP+ ports and 2 40GbE QSFP+ ports, with 168 Gbps unidirectional or 336 Gbps bidirectional switching capacity. It runs on a 150 W AC supply; the PoE version, the EX3400-48P, has 48 PoE or PoE+ ports on a 920 W supply. Up to 10 EX3400 switches join a Virtual Chassis, at 160 Gbps over the QSFP+ ports or 80 Gbps over SFP+. Its CPU is a dual core 1 GHz with 2 GB of DRAM with ECC and 2 GB of flash. The EX3400-48T moves air front to back and the EX3400-48T-AFI back to front.
The EX4400-48F gives 456 Gbps unidirectional or 912 Gbps bidirectional and 678 Mpps; the EX4400-48T gives 348/696 Gbps and ships with two PSU slots and one 550 W AC supply. The PoE EX4400-48P runs on dual load-sharing, hot-swappable 1600 W AC supplies. Up to 10 EX4400 units join a Virtual Chassis over a 400 Gbps interconnect. The CPU is a 2.2 GHz quad-core Intel x86 with 4 GB of DRAM and 20 GB of storage, and an extension slot takes modules such as the EX4400-EM-4S with 4 1/10GbE SFP+ ports.
EX4550 and EX4650: 10GbE and 25GbE
The EX4550-32T-AFI has 32 10GBASE-T ports and expansion module slots in 1U, with back to front airflow, and the EX4550-32F has 32 1/10GbE SFP+ ports on a 650 W AC or DC supply. Expansion modules include the EX4550-EM-8XSFP (8 SFP+ or SFP ports), the EX4550-EM-8XT (8 100M/1G/10GBASE-T ports) and the EX4550-VC1-128G, a 128 Gbps Virtual Chassis module whose cables are sold separately. With 1 AC supply the switch weighs 19.4 lb (8.8 kg).
The EX4650-48Y has 48 25/10/1GbE SFP28/SFP+/SFP ports and 8 100/40GbE QSFP28/QSFP+ ports in 1 U. It gives 2 Tbps unidirectional or 4 Tbps bidirectional, 2976 Mpps at wire speed, latency as low as 550 nanoseconds and a total of 32 MB of shared buffers. The DC model, the EX4650-48Y-DC-AFO, runs on 2 650 W DC supplies, 1+1 and hot-pluggable.
Uplink modules, rack kits and power supplies
The EX4300 takes the EX-UM-4X4SFP (4 1/10GbE SFP+/SFP ports), the EX4300-32F takes the EX-UM-8X8SFP (8 ports), and the EX4300-48MP takes the EX-UM-4SFPP-MR. The EX4200 takes the EX-UM-4SFP, EX-UM-2X4SFP and EX-UM-2XFP uplink modules, and the EX-PWR-320-AC (320 W) or the 930 W EX-PWR2-930-AC and EX-PWR3-930-AC supplies. The EX-RMK and EX-4PST-RMK are the 2 post and 4 post rack mount kits.
Juniper's JPSU supplies carry their rating in the part number and their airflow in the suffix. The JPSU-150-AC-AFO and JPSU-150-DC-AFO (150 W, front to back) fit the EX3400 and EX4100; the JPSU-350-AC and JPSU-550-DC supplies fit the EX4300, AFO front to back and AFI back to front; the JPSU-650W-AC-AO fits the EX4650, the MX204 and the QFX5120-48T and QFX5120-48Y.
What to check before you buy
- The airflow suffix: AFO parts move air front to back and AFI parts back to front, and the supplies and fans in one switch match.
- The PoE budget: the EX3400-48P runs PoE on a 920 W supply, the EX3400-48T has no PoE on its 150 W supply.
- The stacking path: the EX3400 stacks at 160 Gbps over QSFP+ or 80 Gbps over SFP+, the EX4400 over a 400 Gbps interconnect.
- The uplink module for the exact EX4300 model: the 32F takes the EX-UM-8X8SFP and the 48MP the EX-UM-4SFPP-MR.
Lifecycle: what the dates mean
Juniper gives June 30, 2019 as the end of sale date for the EX4550-32T-AFI, the EX4550-EM-8XSFP and the EX4550-FANMODULE-AFO. Among the uplink modules, the EX-UM-4X4SFP reached end of sale on March 31, 2024 and the EX-UM-8X8SFP on March 31, 2026, and the EX-UM-4SFPP-MR follows on December 29, 2026. The EX4300 JPSU-350 and JPSU-550 supplies reached it on March 31, 2026. After end of sale a part can no longer be ordered new from Juniper, and a tested unit is the way to match what is already installed.
Where to look
Each model has its own page listing what is in stock: the EX3400, EX4400, EX4550 and EX4650, with EX accessories, JPSU power supplies and the whole EX Series. Pages in stock today include the EX4650-48Y AFO, the EX4400-48F, the EX3400-48P and the JPSU-650W-AC-AO. For the EX4300 against the EX4600, read Juniper EX4300 vs EX4600; for the whole maker, the Juniper guide. Request a quote for a part that is not listed, or sell the switches you retire.
