juniper QFX Series QFX5120-48Y
The Juniper QFX5120-48Y is a high-speed 1U datacenter top-of-rack leaf switch delivering 48 ports of 10G/25G SFP28 and 8 ports of 40G/100G QSFP28 uplinks. Powered by Broadcom Trident 3 silicon and running Junos OS with EVPN-VXLAN, the QFX5120-48Y provides 4 Tbps of line-rate switching capacity and rich telemetry streaming. Reseller channels and secondary brokers see exceptionally high liquidity for the QFX5120-48Y as cloud providers and enterprise datacenters standardize server connections on 25GbE.
Specifications
| Brand | juniper |
|---|---|
| Family | QFX Series |
| Form factor | 1U fixed switch |
| Released | Jun 2018 |
| Ports | 48x 10G/25G SFP28 and 8x 40G/100G QSFP28 uplinks |
| Switching capacity | 4 Tbps / 2.97 Bpps forwarding capacity |
| Silicon | Broadcom Trident 3 programmable datacenter packet processing silicon |
| Overlays | Hardware-accelerated EVPN-VXLAN Layer 2/Layer 3 gateway and DCI functionality |
| Telemetry | Comprehensive Junos telemetry streaming, Python on-box scripting, and open APIs |
Generations
- Previous generation: juniper QFX Series QFX5110-48S
Works together
How the juniper QFX Series QFX5120-48Y connects to servers, storage and the network: 3 ways, with the parts and products on each path.
iSCSI and NVMe/TCP over Ethernet
Keep the speed the same at all three points: a 25GbE server, a 25GbE switch port and a 25GbE array port. Mixed speeds work but the slowest link sets the pace.
Servers
Dell PowerEdge R240 1U rack
Dell PowerEdge R340 1U rack
Dell PowerEdge R740xd2 2U rack
Dell PowerEdge R840 2U rack
Dell PowerEdge R940xa 4U rack
HPE Apollo 4200 Gen10 2U rack
Adapters for the server
BCM957414A4142CC Broadcom NetXtreme-E BCM57414 Dual-Port 25GbE SFP28 PCIe 3.0 Ethernet Network Adapter
540-BBGY Dell Broadcom 57414 Dual Port 10/25GbE SFP28 PCIe Low Profile Network Adapter
540-BBHB Dell Broadcom 57414 Dual Port 10/25GbE SFP28 OCP 3.0 Mezzanine Network Adapter
540-BBJL Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC)
Storage
Lenovo ThinkSystem DE4000H 2U rack
Lenovo ThinkSystem DM5000H 2U rack
Lenovo ThinkSystem DM7000H 3U rack
Dell Unity XT 380F 2U rack
Dell Unity XT 380XT 2U rack
Dell Unity XT 480F 2U rack
Optics
SFP-25G-SR Arista 25GBASE-SR SFP28 Optical Transceiver
SFP-25G-SR-S Cisco 25GBASE-SR SFP28 Optical Transceiver
407-BCBF Dell 25GbE SFP28 SR Optical Transceiver (850nm, 100m MMF)
File storage (NFS and SMB)
Front-end ports face the clients; back-end ports (on scale-out systems) connect the nodes to each other and need their own switch pair.
Servers
- Dell PowerEdge R240 1U rack
- Dell PowerEdge R340 1U rack
- Dell PowerEdge R740xd2 2U rack
- Dell PowerEdge R840 2U rack
- Dell PowerEdge R940xa 4U rack
- HPE Apollo 4200 Gen10 2U rack
Adapters for the server
- BCM957414A4142CC Broadcom NetXtreme-E BCM57414 Dual-Port 25GbE SFP28 PCIe 3.0 Ethernet Network Adapter
- 540-BBGY Dell Broadcom 57414 Dual Port 10/25GbE SFP28 PCIe Low Profile Network Adapter
- 540-BBHB Dell Broadcom 57414 Dual Port 10/25GbE SFP28 OCP 3.0 Mezzanine Network Adapter
- 540-BBJL Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC)
Storage
- Lenovo ThinkSystem DM5000H 2U rack
- Lenovo ThinkSystem DM7000H 3U rack
- Dell Unity XT 380F 2U rack
- Dell Unity XT 380XT 2U rack
- Dell Unity XT 480F 2U rack
Dell Unity XT 480XT 2U rack
Optics
- SFP-25G-SR Arista 25GBASE-SR SFP28 Optical Transceiver
- SFP-25G-SR-S Cisco 25GBASE-SR SFP28 Optical Transceiver
- 407-BCBF Dell 25GbE SFP28 SR Optical Transceiver (850nm, 100m MMF)
Hyperconverged cluster
Plan at least two 25GbE ports per node to two switches; all-NVMe clusters often move to 100GbE.
HCI nodes
Dell VxRail P Series P570F 2U rack (1 node)
HPE SimpliVity 325 Gen10 1U rack
HPE SimpliVity 380 Gen10 2U rack
HPE SimpliVity 380 Gen9 2U rack
Adapters for the server
- BCM957414A4142CC Broadcom NetXtreme-E BCM57414 Dual-Port 25GbE SFP28 PCIe 3.0 Ethernet Network Adapter
- 540-BBGY Dell Broadcom 57414 Dual Port 10/25GbE SFP28 PCIe Low Profile Network Adapter
- 540-BBHB Dell Broadcom 57414 Dual Port 10/25GbE SFP28 OCP 3.0 Mezzanine Network Adapter
- 540-BBJL Dell Mellanox ConnectX-4 Lx Dual Port 25GbE SFP28 Network Daughter Card (rNDC)
Optics
- SFP-25G-SR Arista 25GBASE-SR SFP28 Optical Transceiver
- SFP-25G-SR-S Cisco 25GBASE-SR SFP28 Optical Transceiver
- 407-BCBF Dell 25GbE SFP28 SR Optical Transceiver (850nm, 100m MMF)
Plan and size it
- Draw this setup in the topology planner mrplanb.com
- Add up rack power and space rack-density.com
- iSCSI explained mrplanb.com
- Virtualization storage Ledger: scored storage platforms mrplanb.com
- Network monitoring tools compared mrplanb.com
Check compatibility with Juniper
Before you buy, confirm the exact configuration against the vendor's own lists: firmware levels, operating systems, adapters and optics that Juniper has tested with the juniper QFX Series QFX5120-48Y.
- Compatibility Juniper Hardware Compatibility Tool (optics and modules)
- Specifications Juniper TechLibrary
- Support Juniper Support
Equivalent models from other brands
FAQ
Can the 25G SFP28 ports auto-negotiate to 10G and 1G?
Yes, the SFP28 ports support 10G and 1G speeds to connect legacy servers and appliances.
Does the QFX5120-48Y support symmetric IRB in EVPN-VXLAN?
Yes, it fully supports symmetric and asymmetric Integrated Routing and Bridging (IRB) in EVPN fabrics.
Buying or selling QFX5120-48Y?
New, refurbished or used. Tell us the quantity and condition and we connect you with a vetted reseller in your region, usually within one working day.
Sources
- Juniper QFX5120-48Y Product Overview, checked 2026-10-27
- Juniper QFX5120-48Y Datasheet, checked 2026-10-27