If you are using eDirectory then putting ldap1.example-cloud.com,ldap2.example-cloud.com will tell webNetwork to use ldap1 server until such time that the LDAP port responds. If it stops responding then it will flip to ldap2. It will stay at ldap2 until ldap2 goes away.
With Microsoft Active Directory this is a bit more tricky due to the way MS LDAP works. MS LDAP utilized DNS to know what all of the domain controllers (LDAP Servers) names are. It does not matter if a server is up or down, if the server is in DNS then there is a chance we will be told to connect to it. This is different from how workstations talk to a domain controller. So you can put dc1.example-cloud.com,dc2.example-cloud.com and it will talk to dc1 until it goes away and then moves to dc2.
Please note that if for example, dc1 goes down, during communication with dc2, webNetwork may be referred to dc1 for the reason that MS LDAP does not have any means for knowing that a dc is down without you the administrator removing it from DNS. Another problem may be that in your host file of UW server you have hard coded your domain example-cloud.com to be the IP address of one of the DC servers. This is another oddity with Microsoft LDAP, it uses the domain name to look up the IP address. In a typical environment, this may resolve to more than one IP address. When you do not hard code it to one specific ip address that webNetwork should talk to, sometimes you will see some delays because we connect to one dc and then get told to go talk to another dc over and over. Hard coding the domain name to the same IP that is used for the LDAP server in webNetwork.