GBIC (abbreviated by Gigabit Interface Converter) is an interface device that converts gigabit electrical signals into optical signals. The GBIC design can be used for hot-swappable use. GBIC is a interchangeable product that meets international standards. Gigabit switches designed with GBIC interfaces account for a large market share in the market due to their flexible interchangeability.
The SFP (Small Form-factor Pluggable) can be simply understood as an upgraded version of GBIC.