A global server load-balancing (GSLB) switch serves as a proxy to an
authoritative DNS and communicates with numerous site switches that are
coupled to host servers serving specific applications. The GSLB switch
receives from site switches operational information regarding host
servers within the site switches neighborhood. When a client program
requests a resolution of a host name, the GSLB switch, acting as a proxy
of an authoritative DNS, returns one or more ordered IP addresses for the
host name. The IP addresses are ordered using metrics that include the
information collected from the site switches or based on other metric
information. Examples of metrics include weighted site, weighted IP, and
active bindings metrics. The GSLB switch places the address that is
deemed "best" at the top of the list.