Brocade Communications Systems 12.4.00 Manual De Usuario

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.

 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

Client local DNS server 
sends AAAA query for

 www.brocade.com.

The GSLB DNS response
www.brocade.com

. =  2001:db8::56

GSLB DNS response

 www.brocade.com. =  2001:db8::56.

DNS

ZONE CONFIG (ip-list):
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

GSLB  POLICY:
health geographic
dns best-only

GSLB SI ADX

ServerIron ADX with ADNS VIP

VIP: 2001:DB8::56

VIP: 2001:DB8::ab

Site ADX

Site ADX

GSLB Site 1 (US)

GSLB Site 2 (EU)

VIP: 209.157.22.210

Site ADX

Site ADX

GSLB Site 3 (US)

GSLB Site 4 (EU)

VIP: 192.108.22.111

US IPv6 client 

sends DNS request 

for AAAA record for 

www.brocade.com

.

Application traffic

US IPv6 Client (Browser)

Local DNS