Brocade Communications Systems ServerIron ADX 12.4.00 Manual Manual page 235

NOTE
Hash-based persistence is a better choice for GSLB configurations that utilize two GSLB controllers
(that are not in an HA configuration) for the same domain and where site persistence is needed for
a single client that is directed to two GSLB controllers. For more information, see
persistence for IPv6"
Sticky persistence enables the GSLB controller to ensure that the same IP address is sent to a
client sending multiple DNS requests within a configurable period of time. Site persistence is
particularly important in instances where user-specific content is stored at one site (such as a
shopping cart) and redirection to another site would result in a lost session. Sticky persistence
enables the GSLB controller to ensure that the client is directed to the site that was previously
visited.
To return the same IP address for a client that has sent requests previously, the GSLB controller
must save the following information:
•
•
•
This information is saved in a session table when the sticky GSLB persistence is enabled, and the
GSLB controller creates a sticky session for each client within the session table. Each session has a
special user type and source port or destination port number to distinguish from other sessions.
When a new request enters the system, the GSLB controller searches for the client IP and domain
name pair. If a match is found, the previously selected IP address will be returned.
To ensure the selected IP is still valid for the request, the GSLB controller checks for the following
conditions to be true before it returns the reply:
•
•
Enabling sticky persistence for IPv6
Sticky persistence for IPv6 addresses is implemented as a GSLB policy, and it can be applied
globally or on per-host basis.
To enable GSLB globally for all domains, enter commands such as the following on the GSLB
controller:
SLB-Ctrl-ServerIronADX(config)#gslb policy
SLB-Ctrl-ServerIronADX(config-gslb-policy)#sticky
To enable Sticky GSLB for a specific host, enter commands such as the following on the GSLB
controller:
SLB-Ctrl-ServerIronADX(config)#gslb-host-policy test
SLB-Ctrl-ServerIronADX(config-gslb-host-policy-test)#sticky 
SLB-Ctrl-ServerIronADX(config)#gslb dns zone gslb.com
SLB-Ctrl-ServerIronADX(config-gslb-dns-gslb.com)#host-info www gslb-policy test
This example defines a host policy, then applies that policy to the specific host www. The sticky is
one function within the host policy.
Syntax: [no] sticky
ServerIron ADX Global Server Load Balancing Guide
53-1002437-01
on page 225
Client IP address/prefix
Domain name the client requested
Selected IP address for the request
Selected IP still belongs to the requested domain
Selected IP is still active
Advanced GSLB configuration for IPv6
2
"Hash-based
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