Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 140)

130 Brocade Virtual ADX Global Server Load Balancing Guide
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Global Server Load Balancing for IPv6 overview
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FIGURE 7 IPv6 GSLB configuration
The GSLB controller makes decisions based on the GSLB policy. In the example above, both the
IPv6 VIPs were healthy, so client was directed to the IPv6 VIP that was geographically closer based
on the configured policy. If the VIP at the geographically closer site (the US site) was down, the
GSLB controller would direct traffic to the EU site.
1. US IPv6 client (browser) sends a DNS request for the website brocade.com.
2. The client’s local DNS server sends a recursive query for www.brocade.com to the GSLB
controller (a Brocade Virtual ADX with ADNS VIP).
3. The GSLB controller determines that the request is for an IPv6 address (query type AAAA) and
so checks the IPv6 address list and identifies GSLB Site 1 (US) as the optimal IP for clients in
the US based on the configured GSLB policy. (Similarly, a request for an IPv4 address would
have been directed to GSLB Site 3 or Site 4.)
4. The GSLB controller sends a GSLB DNS response with the VIP address (2001:db8::56) to the
local DNS server. Note that the controller only sends the best IP to the querying client because
"dns best-only" is configured in the GSLB policy. In the absence of this configuration, the GSLB
controller would have sent back both IPv6 addresses with the best IP (2001:db8::56) at the top
of the response.