100BASE-SX is a version of Fast Ethernet used over optical fiber. The 100BASE-SX enables desktop networking that defines an affordable migration strategy for 10-megabit-per-second copper or fiber to 100-Mbit/sec fiber. Thus, one can make use of cabling structure capable of Gigabit Ethernet speeds and beyond using 100BASE-SX standards. The 100BASE-SX standard is used for new physical-media-dependent (PMD) interface as well as a means for implementing auto-negotiation. It is designed to be used along with the IEEE 802.3 1998 edition standard. 100BASE-SX standard works with all of the Ethernet and Fast Ethernet equipment that rules the LAN market and are found suitable for high speed network deployments. 100BASE-SX standard supports multi-mode fiber network. Data reach extends up to 4 km and transceivers conforming to this standard are hot-pluggable allowing the network upgradation without switching off the system. It is safe, fast and industry approved and a reliable network expansion component.