Brocade Communications Systems 12.4.00 manual Specifying sticky session prefix lengths

2 Advanced GSLB configuration for IPv6

No special CLI commands need to be issued on the site ServerIron ADX.

Specifying sticky session prefix lengths

To create sticky for a specific group (subnet) of clients, configure a different prefix length for that group. Once configured, the GSLB controller will ensure that DNS clients within the same subnet will be served the same IP address in the GSLB response so long as the IP address belongs to the domain and is active.

By default, the ServerIron ADX creates sticky sessions for every IPv6 DNS client with a prefix length of 128 bits. The ipv6-prefix-lengthparameter enables you to specify an alternative prefix length.

To specify the prefix length, enter commands such as the following:

SLB-Ctrl-ServerIronADX(config)#gslb policy

SLB-Ctrl-ServerIronADX(config-gslb-policy)#sticky ipv6-prefix-length 64

Syntax: [no] sticky ipv6-prefix-length <decimal >

The ipv6-prefix-lengthparameter specifies the prefix length of IPv6 DNS clients. The parameter enables you to aggregate DNS clients into one sticky session. The default prefix length is 128 bits.

NOTE

ServerIron ADX does not support the synchronization of sticky sessions across BPs. With sticky ipv6-prefix-length configured, DNS requests from clients on the same subnet go to different BPs and different sticky sessions will be created on different BPs. However, each individual client will receive the same specific domain IP that it received in its previous DNS request.

Specifying sticky session life times

Sometimes clients do not accept DNS servers, thus creating stale sessions. The sticky GSLB session life time (age) prevents sessions from hanging for extended periods of time.

By default, the life time (age) of sticky sessions is set at five minutes. Use the sticky age command to specify the time (in minutes) that must past before an idle session “times out” and session resources are made available to other clients.

To configure the Sticky GSLB session life time (age), enter commands such as the following:

SLB-Ctrl-ServerIronADX(config)#gslb-host-policy test

SLB-Ctrl-ServerIronADX(config-gslb-host-policy-test)#stick age 5

Syntax: [no] sticky age <value>

The <value> is the number of minutes before sticky session is cleared.

Deleting sticky sessions

The clear gslb ipv6 sticky-sessioncommand enables you to clear all sticky sessions or sticky sessions for a specific client.

Syntax: clear gslb ipv6 sticky-session (all <client-ip>)

The <client-ip>is the IP address or prefix of the client for which sticky session will be deleted. If the all option is used, the sticky sessions for all clients are cleared.

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