The Cisco® 100BASE-X Small Form-Factor Pluggable (SFP) device (Figure 1) is a hot-swappable input/output device that plugs into Fast Ethernet ports. dual-rate Fast/Gigabit Ethernet ports. or Gigabit Ethernet ports of a Cisco switch or router. linking the port with the fiber cabling network.Main features include the following:- Hot-swappable when deployed. the switch or router does not have to reboot- Supports the “pay-as-you-populate” model- Interchangeable with other 100BASE-X SFPs on the same line card- Supports the Cisco quality ID feature that enables the switch or router to identify whether or not the SFP is a Cisco qualified SFP- Optically interoperable with respective 100BASE-X Ethernet interfaces on the same linkCisco 100BASE-FX SFPThe Cisco 100BASE-FX SFP operates on ordinary multimode fiber-optic (MMF) link spans up to 2 kilometers (km) long.GLC-FE-100FX modules operate in Fast Ethernet or dual-rate Fast/Gigabit Ethernet ports of Cisco switches and routers.GLC-FE-100FX-RGD modules operate in Fast Ethernet or dual-rate Fast/Gigabit Ethernet ports of Cisco Industrial Ethernet and SmartGrid switches and routers.GLC-GE-100FX modules operate in Gigabit Ethernet ports of Cisco switches and routers.All these modules are interoperable with industrywide interfaces compliant to the IEEE 100BASE-FX standard.