Geographic location metric, Geographic location, Metric – Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) User Manual
Page 162: Configuring a geographic prefix
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Brocade Virtual ADX Global Server Load Balancing Guide
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Advanced GSLB configuration for IPv6
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Geographic location metric
Brocade Virtual ADX GSLB policies use a number of metrics, including the geographic location of a
server, to evaluate the server IP addresses in an IP list.
Once you configure a geographic region for an IP address prefix, the GSLB Brocade Virtual ADX
determines the geographic region of a server in the following ways:
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For a real address, the geographic region is based on the IP address. If you configure a
geographic prefix that matches the real server IP address, the device obtains the geographic
location of the real server from the geographic prefix entry that you configure.
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For a virtual IP address (VIP), the geographic region is based on the management IP address of
the site ADX device on which the VIP is configured. If you configure a geographic prefix that
matches the management IP address of the site ADX device on which the VIP is configured, the
device obtains the geographic location of the VIP from the geographic prefix entry that you
configure.
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If the management IP address of the remote ADX device at that site is not indicative of the
geographic location, use the geo-location command to specify the region of the GSLB site. For
more information about this command, see
example, if the management IP address is in a private subnet, the address is not indicative of
the ADX device’s geographic location. If you specify the region for the GSLB site, the GSLB
Brocade Virtual ADX uses the region you specify instead of the region of the ADX device’s
management IP address.
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If you configure a geographic prefix entry that matches the management IP address of the
remote ADX device and also specify a geographic location for the GSLB site where the remote
ADX device resides, then the geographic location configured for the GSLB site takes
precedence over the one defined in the user-configured geographic prefix entry. For example,
the geographic region for a VIP configured on the remote ADX device will be obtained from the
geographic location configured for the GSLB site where the remote ADX device resides instead
of the geographic prefix entry that matches the management IP address of the remote ADX
device.
The GSLB Brocade Virtual ADX determines the geographic location of the client as follows: For each
client query, the GSLB Brocade Virtual ADX determines the geographic location from which the
client query came based on its IP address.
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If the IP address prefix of a user-configured geographic prefix entry matches that of the client,
then the geographic location of the client will be as specified in the user-configured geographic
prefix entry.
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If multiple server IP addresses compare equally based on the GSLB metrics above the
geographic metric in the GSLB policy, then the GSLB Brocade Virtual ADX prefers server IP
addresses within the same geographic region as the client query.
Configuring a geographic prefix
Using the geo-prefix command, you can configure the geographic location of an IP address prefix,
or override an existing geographic region for an IP address prefix by configuring a new one.
You can assign one of the following geographic locations to an IP address prefix:
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North America
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South America
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Europe