Global server load balancing for IPv6 overview | 2 |
•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 12 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.
FIGURE 12 IPv6 GSLB configuration
GSLB Site 3 (US) | GSLB Site 4 (EU) | ||
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Local DNS | 2 |
Client local DNS server sends AAAA query for
www.brocade.com.
DNS
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| Site ADX |
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VIP: 192.108.22.111 | VIP: 209.157.22.210 | ||||||
GSLB SI ADX
ServerIron ADX with ADNS VIP
3 | ZONE CONFIG |
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| www.brocade.com. = | 192.108.22.111 |
| www.brocade.com. = | 209.157.22.210 |
| www.brocade.com. = | 2001:db8::56 |
| www.brocade.com. = | 2001:db8::ab |
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US IPv6 client sends DNS request for AAAA record for
www.brocade.com.
The GSLB DNS response www.brocade.com. = 2001:db8::56
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GSLB DNS response
www.brocade.com. = 2001:db8::56.
GSLB POLICY: |
health geographic |
dns |
GSLB Site 1 (US) | GSLB Site 2 (EU) | ||||||
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6
US IPv6 Client (Browser) | Application traffic | VIP: 2001:DB8::ab |
VIP: 2001:DB8::56 |
ServerIron ADX Global Server Load Balancing Guide | 195 |
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