The QSFP-100G-LR4-S is a Cisco-compatible 100G LR4 QSFP28 optical transceiver built for single-mode fiber links up to 10 kilometers. If your infrastructure runs on Cisco and you need dependable, standards-compliant 100G reach without the OEM price tag, this is the module for that job.
It uses four LAN-WDM wavelength lanes in the 1295–1309nm range, multiplexed over a single LC duplex connector. Digital Optical Monitoring (DOM) is fully supported, so you can pull real-time diagnostics — TX power, RX power, temperature, voltage, and bias current — straight from your switch or router CLI. The module is hot-swappable, MSA compliant, and rated for commercial operating temperatures from 0°C to 70°C.
Compliance with IEEE 802.3ba means it meets the electrical and coding interface requirements for clean insertion into Cisco QSFP28 ports on supported platforms — no manual configuration changes needed.
Third-party compatible versions of the QSFP-100G-LR4-S match the optical and electrical performance of the Cisco OEM part, typically at 60–80% lower cost depending on volume. Hytoptodevice supplies these modules with full compatibility testing, along with OEM and white-label options for resellers and large-scale deployments.
| Parameter | Specification |
|---|---|
| Form Factor | QSFP28 |
| Data Rate | 100G (4 x 25G lanes) |
| Protocol | 100GbE, OTU4 |
| Wavelength | 1295 / 1300 / 1304 / 1309 nm (LAN-WDM) |
| Fiber Type | Single-Mode Fiber (SMF) |
| Max Reach | 10 km |
| Connector | LC Duplex |
| Max Power Consumption | 3.5W (typical) |
| Operating Temperature | 0°C to 70°C (commercial) |
| DOM Support | Yes (Tx/Rx power, temp, voltage, bias) |
| Compliance | IEEE 802.3ba, MSA QSFP28 |
| Hot-Swappable | Yes |
| Encoding | 64B/66B |
| FEC | RS-FEC supported (platform dependent) |
Connecting two data center buildings or pods over dark fiber or leased SMF is where the QSFP-100G-LR4-S sees its most common use. At 10km reach, it handles most intra-campus and metro-scale DCI links without requiring amplification or external DWDM equipment.
A typical setup puts Cisco Nexus 9000 series switches at each end, with the modules plugged into QSFP28 line-card ports. The four LAN-WDM wavelengths are multiplexed internally, giving you a single 100G logical link over one LC duplex fiber pair — which keeps your fiber plant clean and your operating costs down.
For operators running spine-leaf architectures across multiple facilities, this module fits naturally into the spine layer where 10km reach and high port density both matter.
Enterprise networks linking regional offices, headquarters, and data center sites over leased dark fiber regularly need 100G LR4 optics at the WAN edge. The QSFP-100G-LR4-S works in Cisco ASR 9000 and ASR 1000 series routers for exactly this role, providing 100G Ethernet hand-off between your core routing layer and the transport network.
DOM support means your NOC team can monitor optical signal health remotely without sending field engineers on-site. Degrading TX power or rising RX loss shows up in your NMS before it turns into an outage.
Large university campuses, hospital complexes, and corporate sites often span distances that push well past what 100G SR4 can handle — SR4 tops out at 100m on OM4 multimode. The QSFP-100G-LR4-S on SMF covers these inter-building runs comfortably, with enough link budget headroom to absorb patch panel and splice losses along the way.
Cisco Catalyst 9500 and 9600 series switches deployed as campus core or distribution nodes support this module natively, giving you 100G uplinks to the data center or WAN edge without pulling new fiber.
ISPs aggregating 100G customer hand-offs or building metro Ethernet rings need optics that hold up reliably across urban fiber plants at distances between 2km and 10km. The QSFP-100G-LR4-S fits that window well.
On Cisco NCS 5500 and NCS 540 platforms, the module supports both 100GbE and OTU4 encapsulation depending on port configuration — giving ISPs the flexibility to use the same optic across Ethernet and packet-optical deployments. Bulk procurement through Hytopt Device, with white-label or OEM options, makes cost management straightforward at scale.
The Cisco platforms below have been validated to support the QSFP-100G-LR4-S in their QSFP28 ports. This list covers the most widely deployed models — always cross-check against Cisco's compatibility matrix for your specific line card or supervisor version.
Note: The QSFP-100G-LR4-S requires a QSFP28 port and is not backward compatible with QSFP+ (40G) ports. On platforms where a port can operate in breakout mode, this module runs as a single 100G interface only.
Q1:What does LR4 mean in QSFP-100G-LR4-S?
A:LR4 stands for Long Range, 4 lanes. The module uses four separate optical wavelengths — 1295nm, 1300nm, 1304nm, and 1309nm — multiplexed over a single fiber pair using LAN-WDM technology. Each lane carries 25 Gbps, adding up to 100 Gbps total. The "LR" designation means up to 10 kilometers on single-mode fiber, which sets it apart from SR4 (short reach, multimode, up to 100m) and ER4 (extended reach, up to 40km).
Q2:What is the difference between QSFP-100G-LR4-S and QSFP-100G-LR4-S=?
A:The part number QSFP-100G-LR4-S refers to the transceiver as a spare or standalone component in Cisco's standard ordering system. The "=" suffix (QSFP-100G-LR4-S=) is Cisco's spare parts designation, used when ordering a replacement module separately rather than as part of a system bundle. Electrically and optically, both are identical. A Cisco-compatible QSFP-100G-LR4-S from Hytoptodevice matches the performance of either variant.
Q3:Will using a third-party QSFP-100G-LR4-S void my Cisco warranty or SmartNet contract?
A:Using a third-party compatible transceiver does not void your Cisco hardware warranty under U.S. law — the Magnuson-Moss Warranty Act applies, and similar protections exist in many other jurisdictions. Cisco may display a warning message when a non-Cisco module is inserted, but this is a software flag, not a hardware restriction. Your switch or router continues to function normally, and SmartNet coverage on the host device is not affected by the transceiver brand. That said, Cisco won't support the third-party module itself — for that, you rely on your transceiver supplier.
Q4:Does the QSFP-100G-LR4-S support DOM (Digital Optical Monitoring)?
A:Yes. HYTOPTODEVICE 100G QSFP28 module supports full DOM functionality, including real-time monitoring of transmit power, receive power, module temperature, supply voltage, and laser bias current. On Cisco platforms, you can read these values using show interfaces or show inventory, or through your NMS. DOM lets you catch optical degradation early — before it causes packet loss or a link failure.
Q5:What fiber type does the QSFP-100G-LR4-S require?
A:It requires single-mode fiber (SMF), specifically OS1 or OS2 grade, with an LC duplex connector — one fiber for transmit, one for receive. It is not compatible with multimode fiber (OM1, OM2, OM3, or OM4). If your existing plant uses multimode, you'll need a 100G SR4 or SWDM4 module instead.
Q6:What is the maximum power budget and link loss the QSFP-100G-LR4-S can handle?
A:Typical transmit power is around +2.9 dBm per lane (aggregate), and minimum receiver sensitivity is approximately -10.6 dBm. That gives a working optical power budget of roughly 6.3 dB — enough for 10km of OS2 SMF with typical connector and splice losses. Links shorter than 10km with low-loss fiber will have comfortable headroom. For links approaching the 10km limit with multiple patch panels, measure your link loss before deployment to confirm you're within budget.
Q7:Does the QSFP-100G-LR4-S require FEC (Forward Error Correction)?
A:On clean, well-maintained fiber within its specified reach, the module is designed to operate without FEC. That said, on platforms supporting RS-FEC, enabling it can improve link stability on longer or higher-loss runs. Cisco Nexus 9000 and NCS platforms allow FEC configuration per port. For most standard 10km SMF deployments, FEC is optional — but worth enabling if you're seeing elevated BER or marginal receive power.
Q8:How do I verify that a compatible QSFP-100G-LR4-S module is working correctly after installation?
A:After inserting the module, run show interfaces [interface] transceiver on Cisco IOS-XE or NX-OS to confirm the module is recognized and DOM values are within normal ranges. Check that TX and RX power fall within the specified operating window, and confirm the interface comes up at 100G full duplex with no climbing input errors or CRC counts. Hytopt Device modules ship pre-programmed with Cisco-compatible EEPROM data, so the host device recognizes them without additional configuration. If you see an "unsupported transceiver" warning, this is cosmetic on most Cisco platforms and does not prevent the link from operating.
Hytoptodevice supplies Cisco-compatible QSFP-100G-LR4-S transceivers for data centers, ISPs, enterprises, and telecoms worldwide. Every module is MSA compliant, DOM-enabled, and tested for compatibility with the Cisco platforms listed above. OEM and white-label options are available for resellers and volume buyers who need custom labeling or private-brand packaging.
Whether you need a single module for a lab build or thousands of units for a large-scale rollout, Hytoptodevice offers pricing that consistently runs well below Cisco OEM list price — without cutting corners on optical performance or reliability.
Visit hytoptodevice.com to request a quote, check current stock, or discuss OEM/ODM requirements with the team.
