Cisco QSFP-40/100-SRBD
100G and 40GBASE SR-BiDi QSFP Transceiver, LC, 100m OM4 MMF, Original Cisco
Product Highlights
Upgrading data center or campus interconnects from 10G to 40G or 100G shouldn't mean ripping out your existing fiber plant. The Cisco QSFP-40/100-SRBD is a dual-rate Bi-Directional (BiDi) QSFP28 transceiver that delivers either 40 Gbps or 100 Gbps Ethernet over standard duplex LC multimode fiber — the same two-strand cabling already deployed for 10G links.
This module uses bidirectional optics operating in the 832–918 nm wavelength range, multiplexing two optical channels onto each fiber strand to achieve aggregate bandwidth of 40G or 100G over just two fibers. In 100 Gbps mode, it supports link lengths of up to 70 m on OM3 and 100 m on OM4 multimode fiber. In 40 Gbps mode, reach extends to 100 m on OM3 and 150 m on OM4, covering the vast majority of intra-building and data center distances.
The QSFP-40/100-SRBD is ideal for IT teams planning a phased bandwidth migration. Deploy at 40G today and upgrade to 100G when your switching platforms and traffic demands require it — all without touching the fiber or replacing the optic. Compatible with Cisco Nexus 9000 Series and Catalyst 9500 Series platforms, this transceiver combines investment protection, operational simplicity, and high-density performance in a single hot-swappable module.
Features & Benefits
Dual-Rate 40G/100G Flexibility
The QSFP-40/100-SRBD operates at either 40 Gbps or 100 Gbps, automatically adapting to the host port configuration. This dual-rate capability lets you deploy a single optic SKU across mixed-speed environments and upgrade link speeds non-disruptively as network demands grow.
BiDi Duplex LC Design
Unlike parallel optics that require 8- or 12-fiber MPO/MTP cables, this BiDi transceiver uses standard duplex LC connectors over just two fibers. This means you can reuse your existing 10G duplex MMF infrastructure for 40G or 100G links, dramatically reducing cabling costs and simplifying cable management in dense environments.
Short-Reach Multimode Fiber Support
In 100G mode, the transceiver reaches up to 70 m on OM3 and 100 m on OM4 multimode fiber. In 40G mode, distances extend to 100 m on OM3 and 150 m on OM4. These ranges cover the vast majority of intra-building, data center row-to-row, and campus riser connections.
Digital Optical Monitoring (DOM)
Built-in DOM provides real-time monitoring of key parameters including optical TX/RX power, temperature, and supply voltage via the I2C interface. This enables proactive fault detection and simplifies troubleshooting, reducing mean time to repair.
Low Power, High Density
With typical power consumption of just 3.5 W, the QSFP-40/100-SRBD keeps thermal output low — critical for high-density line cards where dozens of transceivers share limited cooling capacity. Lower power per port translates directly to reduced operational costs.
Deployment Scenarios
Data Center Leaf-Spine Interconnects
Deploy the QSFP-40/100-SRBD in leaf-to-spine uplinks within your data center fabric. Start at 40G and seamlessly upgrade to 100G as east-west traffic grows, all over existing duplex MMF patch cords — no fiber re-cabling required.
10G-to-40G/100G Infrastructure Migration
Organizations with extensive 10G duplex LC multimode fiber plants can migrate to 40G or 100G Ethernet without replacing cabling. The BiDi technology reuses the same two-strand fiber, protecting your infrastructure investment while delivering a 4x–10x bandwidth increase.
Enterprise Campus Core and Distribution
Connect campus core switches to distribution-layer aggregation points at 40G or 100G over in-building multimode fiber runs. The dual-rate capability provides a cost-effective upgrade path as campus bandwidth requirements evolve.
High-Performance Computing (HPC) Clusters
Link compute nodes and storage arrays at 100G over short-reach MMF for low-latency, high-throughput cluster interconnects. The compact QSFP28 form factor supports the high port densities typical of HPC environments.
General
Optical
Electrical / Power
Physical
Environmental
Compliance
Compatibility Notes
Supported Platforms (verify with Cisco's Transceiver Module Compatibility Matrix for your specific software release):
- Cisco Nexus 9000 Series — including N9K-C93180YC-EX, N9K-C93180YC-FX, N9K-C93180YC-FX3, N9K-C9336C-FX2, N9K-C9364C, N9K-C9504
- Cisco Catalyst 9500 Series
Interoperability Note: The QSFP-40/100-SRBD can interoperate with the older QSFP-40G-SR-BD in 40G mode. When connecting to a 40G-only BiDi module, the dual-rate side may require manual speed configuration (speed 40000) and disabling auto-negotiation (no negotiate auto) on certain platforms.
Fiber Requirements: OM3 or OM4 multimode fiber with duplex LC/UPC connectors. Only PC or UPC connector polish types are supported.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| QSFP-40G-SR-BD | Cisco 40GBASE SR BiDi QSFP+ Transceiver | 40G-only BiDi over duplex LC MMF — choose this if you need 40G without a 100G upgrade path |
| QSFP-100G-SR1.2 | Cisco 100GBASE SR1.2 BiDi QSFP28 Transceiver | 100G-only BiDi with PAM4 modulation and 400G-SR4.2 breakout interoperability for future 400G migration |
| QSFP-100G-SR-S | Cisco 100GBASE-SR-S QSFP28 Transceiver | 100G single-wavelength PAM4 over duplex LC MMF — no dual-rate or BiDi, but simpler single-lane design |
| QSFP-40G-SR4 | Cisco 40GBASE-SR4 QSFP+ Transceiver | 40G parallel optics using 12-fiber MPO/MTP — higher fiber count but supports 4×10G breakout mode |
