QSFP-40G-CSR4: Cisco 40GBASE-CSR4 QSFP+ Module
Also listed as: QSFP-40G-CSR4=
Cisco QSFP-40G-CSR4 is listed as Cisco 40GBASE-CSR4 QSFP+ Module. It is a transceiver that the vendor documents for Cisco MDS 9718 show as an orderable option. Spares are ordered as QSFP-40G-CSR4=. Check the exact model and generation before buying, because option lists differ between product generations.
Specifications
| Part number | QSFP-40G-CSR4 |
|---|---|
| Brand | Cisco |
| Type | Transceivers |
| Other numbers | QSFP-40G-CSR4= |
| Speed | 40GbE |
About the QSFP-40G-CSR4
Cisco 40GBASE-CSR4 QSFP+ Module is sold by Cisco under product ID QSFP-40G-CSR4; the same item ordered as a spare carries the suffix = (QSFP-40G-CSR4=). It is a transceiver in the Cisco option range and appears in the ordering or configuration tables of the vendor documents cited in the sources. Key figures taken from the listing: speed 40GbE. The product ID is the number brokers and buyers search for, so match it exactly rather than by capacity or description alone.
Compatibility
The Cisco documents cited in the sources list QSFP-40G-CSR4 as an option for Cisco MDS 9718. That listing is the only compatibility claim recorded here: the part is not assumed to fit other generations or other product lines of the same brand. Firmware, software, slot, backplane and controller requirements are set out in the vendor documentation for the specific product, and the vendor's compatibility tool should be checked before ordering a second-hand unit.
Buying used
Inspect the optical connector for scratches or dirt, read the module details from the switch (vendor name, part number, serial) and confirm the switch accepts it without an unsupported-module warning. Check the speed and reach on the label. Ask the seller for photos of the part number label, confirm the return terms, and test the part in a running system before accepting it. Prices vary with condition, so compare several listings for the exact product ID.
Fits these models
Works together
How the Cisco QSFP-40G-CSR4 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
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
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
- 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
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
Cisco HyperFlex HX220c Edge 1U rack
Cisco HyperFlex HX220c M5 1U rack
Cisco HyperFlex HX220c M6 1U rack
Cisco HyperFlex HX225c M6 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
- 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
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-CSR4.
- Compatibility Cisco UCS Hardware Compatibility List
- Compatibility Cisco Optics-to-Device Compatibility Matrix
- Support Cisco Support and Downloads
Buying or selling QSFP-40G-CSR4?
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
- Cisco MDS 9718 Multilayer Director Data Sheet, checked 2026-10-28