Fusion MIddleware 11g Deployment Guides Available

Hello. we have implemented this using the guide for the LDAP services.. The guide indicates that there should be a persistence set for the LDAP services.. I'm wondering if that is really necessary or required. While this applies to the web-based services, why is it necessary to persist the LDAP connections? The default is source IP and the fallback is destination affinity.. the latter really doesn't load balance if there is any volume of traffic at all.

and if required is the default of 3 minutes correct?

thanks for your help on this.