Currently, to configure the JNDI/LDAP service provider, you specify a URL
containing a machine and port number of the LDAP server. It would be useful
if you can specify more than one server known to offer equivalent service.
This would make the LDAP server provider more tolerant, at least at initial
context creation time, of server failures and network load. Here is the
proposal, which is analogous to how the DNS service provider supports
multiple DNS servers:

    Multiple LDAP servers may be specified by setting the PROVIDER_URL property
    to a space-separated list of URLs. Each of the servers is contacted
    in turn until one of them responds.