Cisco's industry-standard SFP is a hot-swappable input/output device that plugs into a Gigabit Ethernet port/slot, linking the port with the fiber-optic network. SFPs can be used and interchanged on a wide variety of Cisco products and can be intermixed in combinations of IEEE 802.3z- compliant 1000BaseSX, 1000BaseLX/LH, or 1000BaseZX interfaces on a port-by-port basis.
The Cisco GLC-LH-SMD fully complies with the IEEE 802.3z 1000BaseLX standard. However, their higher optical quality allows them to reach 10 km over single-mode fiber (SMF) versus the 5 km specified in the standard.
