Cisco QSFP-100G-ER4L-S
100GBASE QSFP Transceiver, 40KM reach over SMF, Duplex LC, Original Cisco
Product Highlights
Connecting buildings, campuses, or data centers across metropolitan distances at 100 Gbps demands an optic that balances reach, reliability, and power efficiency. The Cisco QSFP-100G-ER4L-S is a 100GBASE ER4-Lite QSFP28 transceiver module engineered to deliver exactly that.
The QSFP-100G-ER4L-S carries the 100 Gigabit Ethernet signal over four LAN-WDM wavelengths (1295.56, 1300.05, 1304.58, and 1309.14 nm), with multiplexing and demultiplexing handled entirely within the module. It supports link lengths of up to 40 km over G.652 single-mode fiber when host-side FEC is enabled, and up to 30 km without FEC — giving network architects flexibility across a range of platform capabilities.
Designed in the industry-standard hot-pluggable QSFP28 form factor with a duplex LC connector, this transceiver integrates seamlessly into Cisco switches and routers with QSFP28 ports. Built-in Digital Optical Monitoring (DOM) provides real-time visibility into link health, while power consumption of ≤ 4.5 W keeps thermal overhead low in dense aggregation and core deployments. The QSFP-100G-ER4L-S also provides backward interoperability with Cisco's CPAK ER4-Lite (up to 25 km) and IEEE 100GBASE-ER4 transceivers such as the CFP 100G ER4 (up to 30 km), as well as with QSFP-100G-LR4-S and CPAK-100G-LR4 modules up to 10 km — protecting your existing fiber investment as you scale.
Features & Benefits
Extended 40 km Reach over Single-Mode Fiber
The QSFP-100G-ER4L-S supports link distances of up to 40 km on G.652 SMF with host FEC, or 30 km without FEC. This makes it ideal for metro-area data center interconnects, campus backbone links, and service-provider edge deployments where distance matters.
4-Lane LAN-WDM Multiplexing
Four 25 Gbps channels at wavelengths of 1295, 1300, 1304, and 1309 nm are multiplexed and demultiplexed within the module, delivering an aggregate 100 Gbps over a single duplex LC fiber pair. This eliminates the need for external mux/demux equipment and reduces fiber count.
Digital Optical Monitoring (DOM)
Integrated DOM provides real-time monitoring of critical parameters including transmit and receive optical power, temperature, supply voltage, and laser bias current. This enables proactive troubleshooting and helps prevent link degradation before it impacts traffic.
Hot-Pluggable QSFP28 Form Factor
The MSA-compliant QSFP28 form factor allows the transceiver to be inserted or removed without powering down the host device. This simplifies upgrades, replacements, and capacity expansion in production environments where uptime is critical.
Broad Interoperability
The QSFP-100G-ER4L-S provides backward compatibility with Cisco's CPAK ER4-Lite (up to 25 km), IEEE 100GBASE-ER4 transceivers like the CFP-100G-ER4 (up to 30 km), and Cisco's QSFP-100G-LR4-S and CPAK-100G-LR4 modules (up to 10 km). This flexibility protects existing infrastructure investments during migration.
Low Power Consumption
With a maximum power draw of ≤ 4.5 W, the QSFP-100G-ER4L-S minimizes thermal impact in high-density line card and switch chassis deployments. Lower heat output translates directly to reduced cooling costs and improved port density.
Deployment Scenarios
Metro Data Center Interconnect (DCI)
Connect geographically separated data centers up to 40 km apart at full 100 Gbps line rate over existing single-mode fiber plant. The ER4-Lite reach eliminates the need for intermediate amplification or regeneration on most metro spans.
Enterprise Campus Backbone
Link core switches across large campus environments — hospitals, universities, corporate headquarters — where building-to-building distances exceed the 10 km limit of LR4 optics. The 30 km FEC-free reach covers the vast majority of campus scenarios.
Service Provider Edge / Aggregation
Deploy at the service provider edge to aggregate 100G uplinks from access rings or customer-premises equipment. The interoperability with CPAK and CFP form factors allows gradual migration from legacy 100G platforms without forklift upgrades.
Disaster Recovery and Business Continuity
Establish high-bandwidth replication links between primary and secondary sites separated by metropolitan distances. The 40 km reach with FEC ensures reliable, low-error data replication for storage and virtualization workloads.
General
Performance
Physical
Power
Environmental
Compliance
Compatibility Notes
The Cisco QSFP-100G-ER4L-S is supported on Cisco switches and routers equipped with QSFP28 100G ports. Supported platforms include the Cisco Nexus 9000 Series, Catalyst 9500 Series, Catalyst 9600 Series, and ASR 9000 Series, among others. For the complete and current list of supported platforms, refer to the Cisco 100 Gigabit Ethernet Transceiver Modules Compatibility Matrix.
Interoperability: Full 40 km reach requires host-side FEC to be enabled on the platform. Without FEC, maximum reach is 30 km. The module interoperates with:
- CFP-100G-ER4 / CFP2-100G-ER4 (IEEE 100GBASE-ER4) — up to 30 km
- CPAK-100G-ER4L — up to 25 km (engineered link)
- QSFP-100G-LR4-S / CPAK-100G-LR4 — up to 10 km
Minimum channel insertion loss is 6.4 dB.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| QSFP-100G-LR4-S | Cisco 100GBASE-LR4 QSFP28 | 10 km reach over SMF without FEC — lower cost option when shorter distances are sufficient |
| QSFP-100G-ZR4-S | Cisco 100GBASE-ZR4 QSFP28 | 80 km reach over SMF — for longer metro/regional spans beyond the ER4L's 40 km range |
| QSFP-100G-SR4-S | Cisco 100GBASE-SR4 QSFP28 | 100 m reach over OM4 MMF with MPO connector — optimized for short-range intra-data-center links |
| QSFP-100G-CWDM4-S | Cisco 100G CWDM4 QSFP28 | 2 km reach over SMF — cost-effective for short single-mode runs within a campus or data center |
