100GBASE-CWDM4 QSFP28 1310nm 2km Module - Compatible for Cisco

In this review of the 100GBASE-CWDM4 QSFP28 1310nm 2km module, the bottom line is straightforward: network engineers and data center technicians who need a compact, standards-compatible 100 Gigabit optical transceiver for single mode fiber will find it a practical, cost-effective choice. The reviewer found the module excels at providing reliable 100GbE links up to 2km with forward error correction (FEC) and integrated digital diagnostics, making it useful for campus aggregation and short metro links where Cisco compatibility and predictable behavior matter.

Key Features

• Compatibility: Works as a replacement for Cisco QSFP-100G-CWDM4-S to provide 100 Gigabit Ethernet interoperability without vendor lock-in.
• High per-lane rate: Supports an aggregate 103.1Gb/s with each lane running at about 25.78Gb/s, enabling full QSFP28 performance for high-throughput links.
• 2km SMF range: Designed for up to 2km transmission over single mode fiber with FEC, suitable for campus backbones and short metro circuits.
• Integrated diagnostics: I2C interface with Digital Diagnostic Monitoring gives real-time telemetry on optical power and temperature for easier troubleshooting.
• Industry compliance: Conforms to IEEE 802.3ba/802.3bm and relevant MSA and SFF specs, easing deployment in mixed-vendor environments.
• Low power footprint: Single +3.3V supply and modest maximum power consumption around 3.5W keep heat and rack power manageable.

Who It's For

This module is aimed at IT professionals operating Cisco-compatible switches and routers who need a plug-in 100G CWDM4 transceiver for short single mode links. It suits network refreshes, cross-connects between data halls, and service provider handoffs where compliance with the 100G CWDM4 MSA and IEEE standards is required.

Those who should look elsewhere include teams needing longer haul DWDM optics, multimode fiber systems, or vendor-branded modules with direct manufacturer support contracts. It is not intended for links beyond the specified 2km single mode range or for environments requiring extended temperature ranges below 0C.

Pros & Cons

Pros

• Standards-based QSFP28 form factor with duplex LC connector supports broad switch compatibility.
• Supports FEC and 2km SMF range, making it practical for many campus and metro links.
• Integrated Digital Diagnostic Monitoring via I2C helps with proactive maintenance and troubleshooting.

Cons

• Operating case temperature is 0 to +70C, so it may not be suitable for extreme temperature environments.
• Not designed for distances beyond 2km, so longer metro or long-haul applications require different optics.

Specifications

Form Factor	QSFP28 MSA
Wavelength	1310nm (CWDM)
Maximum Reach	Up to 2km on Single Mode Fiber with FEC
Power Supply	Single +3.3V
Max Power Consumption	3.5W
Operating Case Temp	0 to +70C
Protocols & Specs	IEEE 802.3ba, IEEE 802.3bm, 100G CWDM4 MSA, SFF-8636/8665

Our Verdict

The 100GBASE-CWDM4 QSFP28 1310nm 2km module is a sensible, standards-compliant option for teams needing a Cisco-compatible 100GbE transceiver for short single mode links. It delivers the expected QSFP28 performance, useful diagnostics, and conservative power draw, making it good value for data center and campus deployments that fit the 2km distance and 0 to +70C operating range.

Frequently Asked Questions

Is this module compatible with Cisco switches?
Yes, it is sold as compatible for Cisco QSFP-100G-CWDM4-S and implements the QSFP28 MSA and related SFF specs to work with many Cisco platforms.

What is the maximum supported distance?
The transceiver supports up to 2km over single mode fiber when used with FEC.

Does it provide diagnostic monitoring?
Yes, it includes an I2C interface with integrated Digital Diagnostic Monitoring for real-time telemetry.