Cisco QSFP-100G-FR-S
100G QSFP28 Transceiver 100G-FR, 2km SMF, duplex, LC, Original Cisco
Product Highlights
As data centers scale and inter-building links demand more bandwidth, deploying cost-effective 100GbE connectivity over single-mode fiber becomes critical. The Cisco QSFP-100G-FR-S is a 100GBASE-FR QSFP28 optical transceiver module purpose-built for this challenge.
This original Cisco transceiver transmits a full 100 Gigabit Ethernet signal over a single 1310nm wavelength using PAM4 modulation and integrated Forward Error Correction (FEC), supporting link lengths of up to 2km over duplex single-mode fiber (SMF) with standard LC connectors. The single-lambda architecture eliminates the complexity of multi-wavelength designs like CWDM4, reducing both cost and optical lane management overhead.
The QSFP-100G-FR-S is compliant with IEEE 802.3cd, the QSFP28 MSA, and the 100G Lambda MSA standard. It supports Digital Optical Monitoring (DOM) for real-time parameter visibility and is designed for hot-pluggable deployment in any Cisco platform with QSFP28 ports. Its single-lambda design also provides a natural upgrade path to 400G — it can interoperate with 400G FR4/XDR4 transceivers via fiber breakout cables, protecting your optics investment as the network evolves.
Whether you're connecting spine-to-leaf tiers in a data center fabric, linking campus buildings, or bridging co-location facilities, the QSFP-100G-FR-S delivers the performance, reach, and future-proofing that modern 100G deployments demand.
Features & Benefits
Single-Lambda PAM4 Architecture
The QSFP-100G-FR-S carries the full 100GbE signal on a single 1310nm wavelength using PAM4 modulation, converting 4×25G NRZ electrical signals into a 1×100G PAM4 optical signal via an onboard DSP gearbox. This eliminates the need for multi-wavelength multiplexing, reducing component complexity and improving reliability compared to legacy CWDM4 designs.
Forward Error Correction (FEC)
Integrated RS-FEC (per IEEE 802.3cd) detects and corrects bit errors at the receiving end, ensuring data integrity across the full 2km link budget. FEC is essential for PAM4-based optics and enables the transceiver to maintain low bit-error rates even in environments with marginal optical signal-to-noise ratios.
Digital Optical Monitoring (DOM)
Real-time diagnostic data — including transmit/receive optical power, temperature, voltage, and bias current — is accessible via the standard I2C/QSFP28 MSA management interface. DOM enables proactive monitoring and faster troubleshooting, reducing mean time to repair and helping network teams maintain SLA compliance.
400G Breakout Interoperability
The single-lambda design of the QSFP-100G-FR-S aligns with the IEEE 400GBASE-FR4 framework, allowing it to interoperate with 400G QSFP-DD transceivers via 4×100G fiber breakout cables. This means you can begin upgrading spine switches to 400G while retaining your existing 100G leaf optics — a significant advantage for phased migration strategies.
Hot-Pluggable QSFP28 Form Factor
The compact, MSA-compliant QSFP28 form factor supports hot-swap insertion and removal without powering down the host device. This simplifies maintenance windows and enables non-disruptive upgrades across high-density switch and router line cards.
Deployment Scenarios
Data Center Interconnect (DCI)
Connect compute halls, storage arrays, or co-location cages within a campus-scale data center over runs up to 2km. The single-lambda design keeps per-port optics cost low while delivering full 100GbE line-rate throughput over standard duplex SMF.
Spine-to-Leaf Fabric Links
Deploy the QSFP-100G-FR-S on 100G uplinks between leaf and spine switches in a Clos fabric. Its 2km reach covers typical inter-row and inter-floor distances, and its 400G breakout compatibility provides a clear path to spine-tier upgrades.
Enterprise Campus Backbone
Bridge campus buildings or MDF/IDF closets separated by up to 2km of single-mode fiber. The FR standard's reach fills the gap between short-reach DR (500m) and longer-reach LR (10km) optics, offering the right balance of distance and cost for many campus topologies.
400G-to-100G Migration / Breakout
Pair the QSFP-100G-FR-S with a 400G FR4 or XDR4 transceiver on the far end using a breakout fiber cable. This enables a single 400G port to serve four independent 100G connections, maximizing port utilization during phased network upgrades.
General
Performance
Standards & Compliance
Environmental
Compatibility Notes
The Cisco QSFP-100G-FR-S is supported on Cisco switches and routers equipped with QSFP28 ports. For the definitive list of supported platforms and minimum software versions, consult the Cisco 100 Gigabit Ethernet Transceiver Modules Compatibility Matrix.
Key notes:
- Requires host-based RS-FEC to be enabled on the port (per IEEE 802.3cd).
- Uses standard duplex LC/UPC connectors over OS2 single-mode fiber.
- Interoperates with other 100GBASE-FR1 compliant transceivers.
- Can interoperate with 400G FR4 / XDR4 transceivers via fiber breakout cables for 4×100G applications.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| QSFP-100G-DR-S | Cisco 100GBASE-DR QSFP28 | Single-lambda 100G for shorter 500m SMF reach — lower cost option when link distances are under 500m |
| QSFP-100G-LR-S | Cisco 100GBASE-LR QSFP28 | Single-lambda 100G for extended 10km SMF reach — choose when inter-building distances exceed 2km |
| QSFP-100G-CWDM4-S | Cisco 100GBASE-CWDM4 QSFP28 | Legacy 4-wavelength 100G design for 2km SMF — FR-S offers simpler single-lambda architecture at similar reach |
| QSFP-100G-LR4-S | Cisco 100GBASE-LR4 QSFP28 | 4-wavelength 100G for 10km SMF — older NRZ-based design vs. FR-S's modern single-lambda PAM4 approach |
