Cisco GLC-GE-100FX
100BASE-FX SFP for GE SFP, Original Cisco
Product Highlights
When your Cisco switch chassis only offers Gigabit Ethernet SFP cages but you still need to reach a legacy 100BASE-FX fiber segment, the Cisco GLC-GE-100FX is the purpose-built solution. A standard 1000BASE-SX or 1000BASE-LX SFP cannot simply be configured to run at 100 Mbps — its optical PHY is fixed at 1 Gbps. The GLC-GE-100FX exists specifically to fill that gap.
This original Cisco SFP transceiver module plugs into a Gigabit Ethernet SFP port and delivers 100 Mbps full-duplex connectivity over multimode fiber (MMF) at a 1300 nm wavelength, with link distances up to 2 km. Internally, the module presents a 1.25 Gbps SGMII signal to the host port while running 100BASE-FX on the optical side — the speed conversion is handled transparently by the module's built-in PHY.
Ideal for campus access layers, industrial floors, and branch offices where legacy 100 Mbps fiber runs terminate at upgraded Cisco Catalyst or Industrial Ethernet switches, the GLC-GE-100FX protects your existing fiber investment while letting you standardize on modern GE-capable platforms. It is hot-swappable, IEEE 802.3u compliant, and uses a standard dual LC connector compatible with 50/125 µm and 62.5/125 µm MMF cables.
Features & Benefits
100BASE-FX for Gigabit Ethernet Ports
The GLC-GE-100FX is specifically designed to operate in Gigabit Ethernet SFP ports on Cisco switches and routers. Its built-in PHY uses SGMII to bridge the GE host interface down to a 100 Mbps optical lane, so you can connect legacy Fast Ethernet fiber segments without needing a separate media converter or a switch with dedicated FE SFP slots.
Multimode Fiber — Up to 2 km
Operating at 1300 nm over standard multimode fiber (50/125 µm or 62.5/125 µm), the module supports full-duplex links up to 2 km. This reach covers most intra-campus and inter-building fiber runs, letting you reuse existing MMF infrastructure without re-cabling.
Hot-Swappable & Easy to Deploy
Like all SFP modules, the GLC-GE-100FX is hot-swappable — insert or remove it without powering down the switch. The module presents a fixed 100 Mbps full-duplex link, so explicit speed configuration on the host side is generally not required. On dual-purpose uplink ports, you may need to set the media type to SFP via the CLI.
Standards-Based Interoperability
Fully compliant with IEEE 802.3u (100BASE-FX), the module interoperates with any standards-compliant 100BASE-FX endpoint — including third-party switches, media converters, and industrial Ethernet devices on the far end of the fiber link.
Investment Protection
By enabling 100 Mbps fiber connectivity on modern GE-only Cisco platforms, the GLC-GE-100FX lets you upgrade your switch infrastructure without being forced to simultaneously upgrade every fiber endpoint. Migrate to Gigabit at your own pace while keeping legacy segments operational.
Deployment Scenarios
Campus Access Layer — Legacy Fiber Uplinks
You've refreshed your campus access switches to Cisco Catalyst models with GE-only SFP uplinks, but existing inter-building fiber runs terminate at 100BASE-FX endpoints. The GLC-GE-100FX lets the new switches connect to those legacy segments without re-cabling or deploying external media converters.
Industrial & Plant-Floor Networking
Factory-floor controllers and industrial Ethernet devices often use 100BASE-FX fiber for noise immunity and distance. Inserting a GLC-GE-100FX into a Cisco Industrial Ethernet switch's GE SFP port provides a direct, standards-compliant optical link to those endpoints.
Branch Office or Remote Site Connectivity
Remote sites that terminate 100 Mbps multimode fiber can be connected to a centrally upgraded Cisco switch chassis. The GLC-GE-100FX bridges the speed gap, avoiding a costly forklift upgrade of the remote-site equipment.
Phased Gigabit Migration
Organizations migrating from Fast Ethernet to Gigabit can deploy GLC-GE-100FX modules as a transitional step — running 100 Mbps today on GE-capable hardware, then swapping in 1000BASE-SX SFPs when the far-end equipment is upgraded.
General
Optical
Power
Environmental
Compliance
Compatibility Notes
Host Port Requirement: The GLC-GE-100FX is designed exclusively for Gigabit Ethernet SFP ports on Cisco switches and routers. It is not intended for Fast Ethernet SFP ports (use GLC-FE-100FX for those) and is not compatible with media converters, NICs, or third-party platforms.
Supported Platforms (examples — always verify against Cisco's official 100-Megabit Ethernet SFP Modules Compatibility Matrix):
- Cisco Catalyst 3750 Series
- Cisco Catalyst 3560 Series
- Cisco Catalyst 2970 Series
- Cisco Catalyst 2960 Series (GE-capable models)
- Selected Cisco Industrial Ethernet (IE-2000, IE-3000, IE-4000) switches
- Selected Cisco Catalyst 3650, C9300, C9400, C9500 platforms
Firmware: Most modern Cisco IOS and IOS-XE releases support this module natively. Confirm the minimum software version for your specific platform in Cisco's compatibility matrix before ordering.
Fiber: Standard 50/125 µm (OM2/OM3/OM4) or 62.5/125 µm (OM1) multimode fiber with LC connectors.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| GLC-FE-100FX | Cisco 100BASE-FX SFP for FE Ports | Designed for Fast Ethernet or dual-rate FE/GE SFP ports — use this if your switch has dedicated FE SFP slots. |
| GLC-FE-100LX | Cisco 100BASE-LX10 SFP for FE Ports | Single-mode fiber, 10 km reach — choose this for longer distances over SMF on FE/dual-rate ports. |
| GLC-FE-100FX-RGD | Cisco 100BASE-FX SFP (Rugged) | Extended temperature range (-40°C to 85°C) for Industrial Ethernet and SmartGrid deployments on FE ports. |
| GLC-SX-MMD | Cisco 1000BASE-SX SFP | Full Gigabit (1000 Mbps) over MMF — use this when both ends support GE and you no longer need 100 Mbps. |
