Brocade Virtual ADX Global Server Load Balancing Guide (Supporting ADX v03.1.00) - Manual (Page 139)

Brocade Virtual ADX Global Server Load Balancing Guide 129
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Global Server Load Balancing for IPv6 overview
2
Fragmentation
Fragmentation is not supported in this release. Customers should either configure an active-only
policy or best-only policy (refer to
“Configuring DNS response parameters” on page 161) or ensure
that the number of IP addresses configured in the IP list is small enough to avoid fragmentation
(i.e., assuming a full length query name (255 bytes)):
• If the client does not advertise EDNS0 header with a buffer larger than 512 bytes, eight IPv6
addresses per host are supported in the response.
• If the client advertises EDNS0 header with a buffer smaller than 512 bytes, forty IPv6
addresses per host are supported in the response.
GSLB for IPv6 example
Typically, GSLB for IPv6 is used to distribute IPv6 traffic to multiple sites for load balancing,
geographic proximity, or redundancy.
Figure 7 shows a deployment of IPv6 GSLB in DNS cache proxy with DNS override mode. The GSLB
controller acts as the authoritative DNS server for the www.brocade.com domain. The domain IPs
for www.brocade.com are a mix of IPv4 and IPv6 addresses. When the GSLB controller receives
DNS queries from resolvers (local DNS), it generates a response based on a configured GSLB
policy.
In this example, the GSLB controller sees that the client is geographically closer to the US site and,
therefore, directs application traffic to the closer VIP.