QSFP-40G-LR4-AR: Arista 40GBASE-LR4 QSFP+ Optical Transceiver Module
Also listed as: QSFP-40G-LR4, QSFP-40G-LR4-C
The Arista QSFP-40G-LR4-AR is a 40GBASE-LR4 QSFP+ optical transceiver delivering 40 Gigabit Ethernet up to 10 kilometers over duplex single mode fibre for data center backbones.
Specifications
| Part number | QSFP-40G-LR4-AR |
|---|---|
| Brand | Arista |
| Type | Transceivers |
| Other numbers | QSFP-40G-LR4, QSFP-40G-LR4-C |
| Status | current |
| Form factor | QSFP+ |
| Speed | 40GbE |
| Wavelength nm | 1,310 |
| Connector | LC duplex |
| Cable type | Single Mode Fibre |
| Max distance m | 10,000 |
About the QSFP-40G-LR4-AR
The Arista QSFP-40G-LR4-AR optical transceiver delivers long-reach 40 Gigabit Ethernet connectivity for data center campus interconnects and building core aggregation links. It integrates four CWDM optical wavelength channels across 1271, 1291, 1311, and 1331 nanometers over standard duplex single mode fibre up to 10 kilometers.
Compatibility
Compatible with Arista 7050QX, 7060CX, 7280CR, and 7500 Series modular chassis. It operates natively in QSFP+ ports, delivering high throughput backbone links across enterprise networks without external multiplexing hardware or separate optical amplifiers in data center facilities.
How to identify a genuine unit
Enclosed in a full metal QSFP+ casing with a blue pull tab extraction handle denoting longwave single mode optical operation. The label specifies part designation QSFP-40G-LR4, Arista Networks branding, serial number, and laser safety class 1 compliance.
Buying used
Inspect the duplex LC optical receptacle with a microscope to verify clean optical surfaces. Seat the module in a live switch port to verify that Arista EOS recognizes the transceiver, powers up all four internal CWDM laser lanes, and reports steady optical telemetry.
Fits these models
- Arista 7050X 7050CX3-32S
- Arista 7050X 7050QX-32S
- Arista 7050X 7050SX-64
- Arista 7050X 7050SX-72Q
- Arista 7050X 7050SX2-128
- Arista 7050X 7050TX-64
- Arista 7050X 7050TX3-48C8
- Arista 7060X 7060CX-32S
- Arista 7060X 7060CX2-32S
- Arista 7060X 7060DX4-32
- Arista 7060X6-32D
- Arista 7260X 7260CX3-64
- Arista 7280R 7280CR-48
- Arista 7280R 7280CR2-60
- Arista 7280R 7280SE-64
- Arista 7280R 7280SR-48C6
- Arista 7280R 7280SR2K-48C6
Works together
How the Arista QSFP-40G-LR4-AR connects to servers, storage and the network: 3 ways, with the hardware 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.
Adapters for the server
540-BDBX Dell NVIDIA Mellanox ConnectX-6 Dx Dual Port 100GbE QSFP56 PCIe Adapter
540-BDCF Dell Intel E810-CQDA2 Dual Port 100GbE QSFP28 PCIe Gen4 Adapter
540-BDCP Dell Broadcom 57508 Dual Port 100GbE QSFP56 PCIe Gen4 Adapter
540-BDCQ Dell Broadcom 57508 Dual Port 100GbE QSFP56 OCP 3.0 Adapter
Switches
Arista 7050X 7050CX3-32S 1U fixed switch
Arista 7050X 7050SX3-48YC8 1U fixed switch
Arista 7050X 7050TX3-48C8 1U fixed switch
Arista 7260X 7260CX3-64 2U fixed switch
Storage
Lenovo ThinkSystem DM7000F 3U rack
Dell Isilon A2000 4U 4-node chassis
Dell Isilon F800 4U 4-node chassis
Dell Isilon F810 4U 4-node chassis
Dell Isilon H400 4U 4-node chassis
Dell Isilon H500 4U 4-node chassis
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.
Adapters for the server
- 540-BDBX Dell NVIDIA Mellanox ConnectX-6 Dx Dual Port 100GbE QSFP56 PCIe Adapter
- 540-BDCF Dell Intel E810-CQDA2 Dual Port 100GbE QSFP28 PCIe Gen4 Adapter
- 540-BDCP Dell Broadcom 57508 Dual Port 100GbE QSFP56 PCIe Gen4 Adapter
- 540-BDCQ Dell Broadcom 57508 Dual Port 100GbE QSFP56 OCP 3.0 Adapter
Switches
- Arista 7050X 7050CX3-32S 1U fixed switch
- Arista 7050X 7050SX3-48YC8 1U fixed switch
- Arista 7050X 7050TX3-48C8 1U fixed switch
- Arista 7260X 7260CX3-64 2U fixed switch
Storage
Dell PowerScale F600 1U rack
Dell PowerScale F900 2U rack
Lenovo ThinkSystem DM5000F 2U rack- Lenovo ThinkSystem DM7000F 3U rack
Lenovo ThinkSystem DM7100F 4U rack
NetApp AFF A20 2U rack
Hyperconverged cluster
Plan at least two 25GbE ports per node to two switches; all-NVMe clusters often move to 100GbE.
HCI nodes
HPE SimpliVity 325 Gen10 Plus v2 1U rack
HPE SimpliVity 380 Gen10 G 2U rack
Lenovo ThinkAgile HX1021 1U edge
Cisco HyperFlex HX220c Edge 1U rack
Adapters for the server
- 540-BDBX Dell NVIDIA Mellanox ConnectX-6 Dx Dual Port 100GbE QSFP56 PCIe Adapter
- 540-BDCF Dell Intel E810-CQDA2 Dual Port 100GbE QSFP28 PCIe Gen4 Adapter
- 540-BDCP Dell Broadcom 57508 Dual Port 100GbE QSFP56 PCIe Gen4 Adapter
- 540-BDCQ Dell Broadcom 57508 Dual Port 100GbE QSFP56 OCP 3.0 Adapter
Switches
- Arista 7050X 7050CX3-32S 1U fixed switch
- Arista 7050X 7050SX3-48YC8 1U fixed switch
- Arista 7050X 7050TX3-48C8 1U fixed switch
- Arista 7260X 7260CX3-64 2U fixed switch
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 Arista
Before you buy, confirm the exact configuration against the vendor's own lists: firmware levels, operating systems, adapters and optics that Arista has tested with the Arista QSFP-40G-LR4-AR.
- Compatibility Arista transceivers and cables
- Support Arista Support
FAQ
What optical cabling does QSFP-40G-LR4-AR require?
It uses standard single mode optical fibre terminated with a duplex LC connector.
What wavelengths are used by the internal CWDM lasers?
It multiplexes four wavelengths at 1271, 1291, 1311, and 1331 nanometers.
Buying or selling QSFP-40G-LR4-AR?
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
- Arista Transceiver and Cable Guide, checked 2026-10-27