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.

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 Grade | Maximum Segment Length |
Single-mode fiber | 5000 meters |
50-micron multimode fiber | 550 meters |
62.5-micron multimode fiber | 440 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.

TIP
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)
See also
External references:
- IEEE Std 802.3™-2012 (Revision of IEEE Std 802.3-2008) – download IEEE 802.3 pdf