Cisco SFP-25G-SR-S Compatible 25GBASE-SR SFP28 850nm 100m Duplex LC MMF DOM Optical Transceiver Module

Overview

This SFP28 module is a high-performance transceiver designed as a fully compatible alternative to the Cisco SFP-25G-SR-S. It provides 25 Gigabit Ethernet connectivity for short-reach applications, delivering reliable data transmission up to 100 meters over OM4 multi-mode fiber (MMF). As an S-Class module, it is optimized for the power, cost, and standard temperature requirements of modern enterprise and data center environments, making it a perfect choice for upgrading server connectivity from 10G to 25G.

The transceiver operates in compliance with the 25GBASE-SR IEEE 802.3by standard. It utilizes a high-reliability 850nm VCSEL laser and features a duplex LC connector. The SFP28 form factor is identical in size to the legacy SFP+, enabling a seamless upgrade path for infrastructure that uses the same physical footprint while delivering 2.5 times the bandwidth. Host systems typically require RS-FEC (Reed-Solomon Forward Error Correction) to ensure error-free operation over the maximum specified distance.

Key Features

• 100% compatible with Cisco platforms supporting the SFP-25G-SR-S module.
• Standard: Compliant with IEEE 802.3by 25GBASE-SR and SFP28 MSA.
• Data Rate: Single rate of 25.78 Gbps.
• Reach: Supports up to 70m on OM3 MMF and 100m on OM4 MMF.
• Wavelength: 850nm VCSEL.
• Connector: Duplex LC.
• S-Class: Optimized for standard operating temperature ranges (0°C to 70°C).
• Built-in Digital Optical Monitoring (DOM/DDM) for real-time performance tracking.
• Hot-pluggable SFP28 form factor.

Applications

The SFP-25G-SR-S compatible module is purpose-built for:

• 25G Ethernet server-to-switch connections (ToR, MoR).
• High-density data center and cloud network interconnects.
• High-speed Storage Area Networks (SAN).
• Upgrading existing 10G network infrastructure to 25G.

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 25GBASE-SR SFP28 optics.

FAQ (Technical & Product Questions)

1. What is the difference between SFP+, SFP28, and this SFP-25G-SR-S module?

SFP+ is a 10G form factor, while SFP28 is a 25G form factor. While they share the same physical size, the SFP28 has an upgraded electrical interface to handle 25Gbps per lane. The SFP-25G-SR-S is an SFP28 module designed specifically for the 25GBASE-SR standard.

2. Can I use this SFP-25G-SR-S module in a 10G SFP+ port?

It depends on the host device (switch, NIC). Many modern switches have dual-rate 10G/25G ports that will accept an SFP28 module and auto-negotiate to 10G if the device on the other end is 10G. However, if the port is strictly a 10G SFP+ port, it will not support a 25G SFP28 module.

3. What does the “-S” suffix on the part number SFP-25G-SR-S indicate?

The “-S” suffix designates this as an S-Class optic. S-Class modules are optimized for standard commercial temperature environments (0°C to 70°C) and are primarily intended for cost-effective enterprise and data center deployments.

4. What kind of fiber patch cable is required for this transceiver?

You need a standard multi-mode fiber (MMF) patch cable with duplex LC connectors. To achieve the maximum distance of 100 meters, OM4 grade fiber is required. For distances up to 70 meters, OM3 fiber is sufficient.

5. Is FEC (Forward Error Correction) required for this module?

Yes, for reliable operation over its specified distance, the host device (switch or network card) must have RS-FEC (Reed-Solomon Forward Error Correction) enabled, as specified by the IEEE 25GBASE-SR standard. Some hosts may also support Base-R FEC (also known as Fire-code FEC), but RS-FEC is more common for SR optics.