QSFP-40G-LR4: Cisco 40GBASE-LR4 QSFP+ Optical Transceiver

Name: QSFP-40G-LR4 Cisco 40GBASE-LR4 QSFP+ Optical Transceiver
Brand: Cisco
SKU: QSFP-40G-LR4

CiscoTransceivers

Also listed as: 10-2673-02, QSFP-40G-LR4=

The Cisco QSFP-40G-LR4 is a 40GBASE-LR4 QSFP+ optical transceiver supporting 40 Gigabit Ethernet single mode links up to 10 kilometers over standard duplex LC fibre.

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Specifications

Part number	QSFP-40G-LR4
Brand	Cisco
Type	Transceivers
Other numbers	10-2673-02, QSFP-40G-LR4=
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

The Cisco QSFP-40G-LR4 transceiver multiplexes four discrete 10Gbps optical channels into a single optical path using coarse wavelength division multiplexing technology. It operates across 1271, 1291, 1311, and 1331 nanometer center wavelengths, transmitting full 40GbE bandwidth across existing duplex single mode structured cabling up to 10 kilometers without requiring multi-fiber ribbon replacement.

Compatibility

Compatible with Cisco Nexus 9000, Nexus 7000, Nexus 3000, and Catalyst 9500 Series switches with 40GbE QSFP+ ports. It is widely deployed for core to distribution links, data center interconnects between buildings, and aggregation layer uplinks requiring long haul single mode infrastructure.

How to identify a genuine unit

Enclosed in a standard QSFP+ casing fitted with a blue color coded pull tab indicating single mode longwave operation. The top surface label contains Cisco corporate branding, part number QSFP-40G-LR4, assembly identifier 10-2673-02, and optical safety compliance information.

Buying used

Verify that optical power levels on all four internal multiplexed lanes fall within factory specifications via switch CLI diagnostic commands. Check the duplex LC connector receptacle for mechanical integrity and confirm that the module latches firmly into switch QSFP+ cages without physical play.

Fits these models

Works together

How the Cisco QSFP-40G-LR4 connects to servers, storage and the network: 3 ways, with the hardware on each path.

iSCSI and NVMe/TCP over Ethernet File storage (NFS and SMB)Hyperconverged cluster

iSCSI and NVMe/TCP over Ethernet

Server10/25/100GbE NICEthernet switchstorage VLAN, two switchesStorage arrayiSCSI or NVMe/TCP ports

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

Cisco Nexus 31108PC-V 1U fixed switch
Cisco Nexus 34180YC 1U fixed switch
Cisco Nexus 93180YC-FX3 1U
Cisco Nexus 93240YC-FX2 1.2U 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

iSCSI and NVMe/TCP over Ethernet: how it fits together

File storage (NFS and SMB)

Server or clientEthernet NICEthernet switchdata or storage VLANNAS or scale-outNFS, SMB, S3 ports

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

Cisco Nexus 31108PC-V 1U fixed switch
Cisco Nexus 34180YC 1U fixed switch
Cisco Nexus 93180YC-FX3 1U
Cisco Nexus 93240YC-FX2 1.2U fixed switch

Storage

File storage (NFS and SMB): how it fits together

Hyperconverged cluster

HCI nodedrives plus 25GbETwo Ethernet switchesstorage and VM trafficMore HCI nodesthree or more

Plan at least two 25GbE ports per node to two switches; all-NVMe clusters often move to 100GbE.

HCI nodes

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

Cisco Nexus 31108PC-V 1U fixed switch
Cisco Nexus 34180YC 1U fixed switch
Cisco Nexus 93180YC-FX3 1U
Cisco Nexus 93240YC-FX2 1.2U fixed switch

Hyperconverged cluster: how it fits together

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 Cisco

Before you buy, confirm the exact configuration against the vendor's own lists: firmware levels, operating systems, adapters and optics that Cisco has tested with the Cisco QSFP-40G-LR4.

Compatibility Cisco UCS Hardware Compatibility List
Compatibility Cisco Optics-to-Device Compatibility Matrix
Support Cisco Support and Downloads

FAQ

What optical reach does the QSFP-40G-LR4 provide?

It provides link distances up to 10 kilometers over standard G.652 single mode fibre.

Does QSFP-40G-LR4 use MPO or duplex LC connectors?

It uses standard duplex LC optical connectors by multiplexing four wavelengths internally.

Buying or selling QSFP-40G-LR4?

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.

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Sources

Cisco 40GBASE QSFP Modules Data Sheet, checked 2026-10-27