Definition of 1000BaseSX in The Network Encyclopedia.

What is 1000BaseSX?

A type of standard for implementing Gigabit Ethernet networks. The SX in 1000BaseSX stands for short, and it indicates that this version of Gigabit Ethernet is intended for use with short-wavelength transmissions over short cable runs of fiber-optic cabling. Gigabit Ethernet standards are defined in the 802.3z standards of Project 802 developed by the IEEE.

1000BaseSX technologies are in the beginning stages of being widely implemented in enterprise-level networks and are primarily used for shorter cable runs between pieces of equipment within a building.

How It Works

1000BaseSX is an extension of standard Ethernet technologies to gigabit-level network speeds. 1000BaseSX is implemented using only multimode fiber-optic cabling. Cable segment lengths depend on the cable grade used, as shown in the following table.

1000BaseSX Cable Segment Lengths

Cable Grade Maximum Segment Length
50-micron multimode fiber
500 meters
62.5-micron multimode fiber
220 meters

1000BaseSX is intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs. 1000BaseSX is most commonly implemented in a switch-switch configuration.


When multimode fiber-optic cabling is used in 1000BaseSX implementations, a condition called differential mode delay (DMD) can sometimes occur. This condition occurs only in cabling of uneven quality, and it leads to signal jitter that can disrupt network communications. To resolve this problem, newer 1000BaseSX transceivers condition the signal to distribute its power equally among all transmission modes of the cable.

Related products

10Gtek for Cisco GLC-SX-MMD/ GLC-SX-MM/ SFP-GE-S, Gigabit SFP SX Transceiver, 1000Base-SX, MMF, 850nm, 550m

Check it out on Amazon