Cisco 100BASE-FX SFP (GLC-GE-100FX=)

The Cisco 100BASE-FX Small Form-Factor Pluggable (SFP) transceiver, designated GLC-GE-100FX=, unlocks reliable fiber connectivity for your Cisco Catalyst environment. This hot-swappable SFP module plugs into a Gigabit Ethernet SFP port on Cisco Catalyst 3750 Series, 3560 Series, and 2970 Series switches, extending your network’s reach with robust 100 Mbps full-duplex fiber links. Built to integrate seamlessly with Cisco’s hardware ecosystem, the GLC-GE-100FX= delivers consistent performance, simplifies upgrades, and reduces downtime. Whether upgrading an existing switch or designing a campus backbone, this SFP is designed to deliver predictable, enterprise-grade fiber performance while maintaining compatibility with Cisco management tools and CLI commands.

• High-performance 100BASE-FX fiber connectivity — This SFP module delivers true 100 Mbps full-duplex Ethernet over fiber, providing fast, reliable data transmission between switches, distribution points, and edge devices. By leveraging fiber optics, it eliminates copper-related interference and electrical noise, enabling stable links across floors and buildings. The 1310 nm optical wavelength supports efficient, long-distance transmission, enabling you to extend your network beyond the limitations of copper cabling while maintaining low latency and consistent throughput.
• Hot-swappable, plug-and-play installation — The GLC-GE-100FX= is designed for quick deployment with minimal downtime. In supported Cisco switches, you can insert or replace the SFP without powering down the chassis, enabling rapid network upgrades or repairs. This capability is particularly valuable for campus networks, data centers, and branch deployments where uptime matters. The module’s compact form factor fits neatly into standard SFP cages, allowing administrators to upgrade quietly during maintenance windows or even during production hours in environments that support hot-swapping.
• Wide compatibility with Cisco Catalyst series — Engineered to work with Cisco Catalyst 3750, 3560, and 2970 switches, this 100BASE-FX SFP integrates with Cisco’s unified management approaches. It supports Cisco’s on-device monitoring, SNMP-based performance tracking, and CLI-based configuration, making it easier to monitor link status, utilization, and error rates. With Cisco’s ecosystem, you can leverage familiar commands to verify interface status, analyze trunk or access port behavior, and ensure that the 100 Mbps link reliably carries the intended traffic.
• LC duplex connector and flexible fiber options — The GLC-GE-100FX= uses a standard LC duplex fiber connector, promoting compatibility with a broad range of fiber optic cabling. It supports multimode fiber (MMF) as a primary option and can accommodate suitable single-mode fiber installations with the appropriate cabling and link budget considerations. This flexibility lets you reuse existing fiber infrastructure and scale your network by choosing the appropriate distance and fiber type for campus backbones, distribution layers, or data center edges.
• Reliability, efficiency, and enterprise-grade performance — Cisco’s SFP modules are designed for robust operation in demanding networks. The 100BASE-FX SFP delivers consistent performance in enterprise environments, with reliable link integrity, error detection, and compatibility with standard Ethernet handshakes. The module’s energy-efficient design and adherence to industry standards contribute to long-term operational stability, reduced maintenance costs, and predictable upgrade paths as your network requirements evolve.

Technical Details of Cisco 100BASE-FX SFP

• Product type — Small Form-Factor Pluggable (SFP) transceiver
• Standard — 100BASE-FX
• Data rate — 100 Mbps (full duplex)
• Wavelength — 1310 nm
• Connector — LC duplex
• Fiber type — Multimode fiber (MMF); compatible with single-mode fiber using appropriate cabling
• Maximum distance — Up to approximately 2 km on MMF; longer distances with SMF depending on fiber and link budget
• Hot-swappable — Yes; designed for plug-and-play installation in supported Cisco switches
• Compatibility — Cisco Catalyst 3750, 3560, and 2970 series switches
• Form factor — SFP optical transceiver module for a Gigabit Ethernet SFP port
• Compliance — SFP MSA compliant; Cisco GLC-GE-100FX= designation

How to install Cisco 100BASE-FX SFP

• Confirm that your Cisco switch supports SFP modules and that you have an available SFP port. Review your device’s documentation for any model-specific guidance on hot-swapping.
• If your environment permits hot-swapping, you can insert the module with the switch powered on; otherwise, follow your maintenance policy and power down the device before installation.
• With care, remove any existing SFP module (if replacing) using the release lever to unlock the module and gently pull it straight out from the SFP cage.
• Hold the GLC-GE-100FX= by the edges and align it with the SFP port. Insert the module firmly into the cage until it is fully seated and the locking mechanism engages. You should hear or feel a small click indicating a secure connection.
• Connect the fiber optic patch cable to the LC duplex connector on the SFP module. Ensure you use the correct duplex orientation and that the cable is clean and free of dust, then route the cable to the remote device with proper bend radii to avoid signal loss.
• On the opposite end, connect the fiber to the corresponding SFP port on the other device (switch, converter, or router) using a matching MMF or SMF link, maintaining proper polarity and avoiding kinks or excessive tension.
• Power on the switch if you powered it down, or proceed with the existing power state if hot-swapping is supported. Monitor the link status indicators on the switch or the CLI to confirm that the interface is up at 100 Mbps in full-duplex mode.
• Verify connectivity using the switch’s management interface. For Cisco devices, check the interface status with appropriate show commands (for example, show interfaces or show interfaces status) and validate that the 100BASE-FX link is active with the expected speed and duplex settings. Adjust speed/duplex as needed to match the remote end.
• Document the new SFP deployment in your network inventory, noting the module part number (GLC-GE-100FX=), port assignment, cable type, and link distance to assist future maintenance and troubleshooting.

Frequently asked questions

• Q: What is the Cisco 100BASE-FX SFP used for? A: It enables 100 Mbps fiber connectivity for Cisco Catalyst switches by extending Ethernet links over fiber, ideal for campus distributions, data center edge connections, and inter-switch links where copper is impractical or prohibited.
• Q: What distance can I reach? A: Distance depends on the fiber type. With multimode fiber, you can typically reach up to ~2 km; with single-mode fiber, longer links are possible according to the fiber specifications and link budget. Always plan based on the actual fiber path and attenuation.
• Q: Is it compatible with other vendors? A: The module follows SFP/MSA standards and is designed for Cisco Catalyst devices. While SFPs can be used in some non-Cisco gear, compatibility varies by vendor, and Cisco-specific features may not be available in non-Cisco environments. Check with the vendor’s compatibility matrix.
• Q: Do I need any special tools to install? A: No specialized tools are required. Handle the module by its edges, avoid touching the connector, and ensure fiber connectors are clean. Use standard fiber patch cables and follow proper ESD precautions when handling components.
• Q: How do I verify a successful link? A: After installation, verify link status through the switch’s LED indicators and CLI commands (for example, show interfaces status). Ensure the port negotiates correctly to 100 Mbps full duplex and that traffic is flowing as intended. If issues arise, check fiber cleanliness, connector type, and fiber compatibility (MMF vs SMF).
• Q: Can I mix SFPs from different vendors? A: While SFPs are designed to follow MSA standards, Cisco devices and features may have best compatibility with Cisco-branded modules. For critical deployments, use Cisco-approved modules to maximize reliability and support alignment.