The present invention provides an active/standby data center that avoids
the delay associated with a cached DNS entry to switch from the active
data center to the standby data center. When the active data center
becomes unavailable, the standby data center advertises the same address
as the primary data center so the change over occurs quickly. When the IP
address of the primary data center is no longer visible to the standby
data center, the standby data center begins to advertise.