Brocade Communications Systems 12.4.00 manual Geographic location metric

2 Advanced GSLB configuration for IPv6

ServerIronADX# configure terminal ServerIronADX(config)# gslb dns zone company.com ServerIronADX(config-gslb-dns-company.com)# host-info www http ServerIronADX(config-gslb-dns-company.com)# host-info www ssl ServerIronADX(config-gslb-dns-company.com)# host-info www http track-port ServerIronADX(config-gslb-dns-company.com)# end

Geographic location metric

ServerIron 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 ServerIron ADX determines the geographic region of a server in the following ways:

•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.

•For a virtual IP address (VIP), the geographic region is based on the management IP address of the site ServerIron ADX on which the VIP is configured. If you configure a geographic prefix that matches the management IP address of the site ServerIron ADX on which the VIP is configured, the device obtains the geographic location of the VIP from the geographic prefix entry that you configure.

•If the management IP address of the remote ServerIron ADX at that site is not indicative of the geographic location, use the geo-locationcommand to specify the region of the GSLB site. For more information about this command, see the “Specifying site locations” on page 217. For example, if the management IP address is in a private subnet, the address is not indicative of the ServerIron ADX’s geographic location. If you specify the region for the GSLB site, the GSLB ServerIron ADX uses the region you specify instead of the region of the ServerIron ADX’s management IP address.

•If you configure a geographic prefix entry that matches the management IP address of the remote ServerIron ADX and also specify a geographic location for the GSLB site where the remote ServerIron ADX 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 ServerIron ADX will be obtained from the geographic location configured for the GSLB site where the remote ServerIron ADX resides instead of the geographic prefix entry that matches the management IP address of the remote ServerIron ADX.

The GSLB ServerIron ADX determines the geographic location of the client as follows: For each client query, the GSLB ServerIron ADX determines the geographic location from which the client query came based on its IP address.

•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.

•If multiple server IP addresses compare equally based on the GSLB metrics above the geographic metric in the GSLB policy, then the GSLB ServerIron ADX prefers server IP addresses within the same geographic region as the client query.

216	ServerIron ADX Global Server Load Balancing Guide
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