Global Server Load Balancing (GLSB) does for data centers what load balancing does for servers. It directs users to the best possible resource (best data center for a resource). Best here can mean, the closest, the healthiest, or the least loaded.
GSLB uses a proprietary protocol called Metric Exchange Protocol (MEP) to obtain the metrics needed for this decision. The result of GSLB processing is an Address (A) record in response to a DNS request that the client will then use to obtain the resource.
In this section, we'll look at what a typical first time flow looks like, what some of the considerations are for GSLB to work correctly, and then move on to troubleshooting.