Cisco QSFP-100G-LR4-S Compatible 100GBASE-LR4 QSFP28 1310nm 10km OS2 DOM Duplex LC SMF Optical Transceiver Module

Overview

This module is a high-performance QSFP28 optical transceiver, engineered as a fully compatible alternative to the Cisco QSFP-100G-LR4-S. It is designed for 100 Gigabit Ethernet long-reach applications, providing a stable and reliable link up to 10 kilometers over standard duplex single-mode fiber (SMF). As an S-Class (“-S”) optic, it is optimized for enterprise and data center environments, offering a cost-effective solution for high-speed network aggregation and core connectivity.

The transceiver operates according to the 100GBASE-LR4 standard, which utilizes four independent 25Gbps data streams on four LAN-WDM (Local Area Network Wavelength Division Multiplexing) wavelengths. These optical signals are multiplexed and transmitted over a single fiber pair, terminating with a standard duplex LC connector. This architecture provides a straightforward upgrade path to 100GbE for networks already using duplex LC cabling infrastructure.

Key Features

• 100% compatible with Cisco platforms that support the QSFP-100G-LR4-S module.
• Standard: Compliant with IEEE 802.3ba 100GBASE-LR4 and QSFP28 MSA.
• Data Rate: 103.1 Gbps aggregate (4 x 25.78 Gbps).
• Reach: Supports link lengths up to 10km on Single-Mode Fiber (OS2).
• Wavelengths: 4 LAN-WDM lanes: 1295nm, 1300nm, 1304nm, 1309nm.
• Connector: Duplex LC/UPC.
• Built-in Digital Optical Monitoring (DOM/DDM) for real-time diagnostics.
• Hot-pluggable QSFP28 form factor.

Applications

The QSFP-100G-LR4-S compatible module is an excellent choice for a wide range of high-speed networking scenarios:

• Data Center Interconnects (DCI) and metro networks.
• Enterprise campus and building backbones.
• 100G Ethernet aggregation and core routing.
• Service provider transport and distribution networks.

Specifications

Cross-Platform Compatibility

Programmed for seamless integration with Cisco equipment, this module’s adherence to MSA standards ensures it can also be deployed in networking hardware from other major manufacturers that support 100GBASE-LR4 QSFP28 optics.

FAQ (Technical & Product Questions)

1. What is the difference between QSFP-100G-LR4-S and QSFP-100G-SR4?

The main differences are the intended reach and fiber type. The LR4 (“Long Reach”) module uses LAN-WDM lasers over single-mode fiber (SMF) for distances up to 10km. The SR4 (“Short Reach”) module uses parallel optics over multi-mode fiber (MMF) for distances up to 100m. They use different connectors (LC for LR4, MPO for SR4) and are not interoperable.

2. Can the QSFP-100G-LR4-S be used for 4x25G breakout?

No. The 100GBASE-LR4 standard uses WDM to combine four 25G channels onto a single fiber pair. It presents only a single 100G interface to the host device and cannot be optically split into four 25G links. For breakout applications, you must use a parallel optics module like the QSFP-100G-PSM4-S.

3. What does the “-S” suffix signify on this module?

The “-S” designates it as an S-Class module in the Cisco portfolio. S-Class optics are specified for standard commercial temperature ranges (0°C to 70°C) and are optimized for enterprise and data center applications, typically offering a more cost-effective solution compared to industrial or service-provider-grade optics with wider temperature ranges.

4. How is 100GBASE-LR4 different from 100GBASE-LR (Single Lambda)?

They are different, incompatible technologies. 100GBASE-LR4 uses four 25Gbps NRZ-modulated lasers on different wavelengths. 100GBASE-LR (e.g., QSFP-100G-LR-S) uses a single 100Gbps PAM4-modulated laser on one wavelength. While both use duplex SMF and achieve similar distances, they cannot be connected to each other.

5. What is the correct fiber cable for connecting two QSFP-100G-LR4-S modules?

To achieve the maximum 10km link distance, you need a standard OS2 single-mode fiber patch cable terminated with Duplex LC/UPC (Ultra Physical Contact) connectors.