Global Server Load Balancing (GSLB) distributes traffic across data centers in different geographic regions.
A user in Tokyo should connect to your Tokyo data center. A user in Paris should connect to your Frankfurt data center. GSLB makes this happen.
GSLB typically uses DNS-based routing. The DNS resolver returns different IP addresses based on the client's location. The client connects to their nearest data center.
GSLB also handles disaster recovery. If Tokyo's data center fails, DNS stops returning Tokyo's IP. Users automatically route to the next nearest location.