Definition of 1000BaseLX in The Network Encyclopedia.

What is 1000Base-LX?

1000Base-LX is a type of standard for implementing Gigabit Ethernet networks. The LX in 1000BaseLX stands for long, and it indicates that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions over long cable runs of fiber-optic cabling.

1000Base-LX SFP
Cisco 1000Base-LX SFP

Gigabit Ethernet standards are defined in the 802.3z standards of Project 802 developed by the IEEE. 1000BaseLX technologies are in the beginning stages of being widely implemented in enterprise-level networks and are primarily used for long cable runs between pieces of equipment on a campus or within a building.

How 1000Base-LX Work?

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

1000BaseLX Cable Segment Lengths

Cable GradeMaximum Segment Length
Single-mode fiber5000 meters
50-micron multimode fiber550 meters
62.5-micron multimode fiber440 meters

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

1000BaseLX network


When you use multimode fiber-optic cabling in 1000BaseLX 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 1000BaseLX transceivers condition the signal to distribute its power equally among all transmission modes of the cable. (Example of 1000Base-LX Transceiver Module)

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