How do you differentiate between East Coast (US) and West Coast (US) users for geographic Global Server Load Balancing (GSLB)?
A: To date, we do not know of any 100 percent accurate geographic IP tables that divide the United States into the East Coast and West Coast. In order for users to do this, they must either modify an existing database or come up with a new one where distance qualifiers are added.
The suggested method of differentiating between East Coast and West Coast users is to use round-trip time (RTT)-based GSLB rather than geographic GSLB. RTT-based GSLB routes users to the topologically closest site which translates into an East Coast/West Coast division for most sites.
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The reason geographic IP systems are not 100 percent accurate is because mapping can be affected by large corporate or ISP networks where traffic is routed out of a small number of access points, regardless of the traffic's point of origin.
