Different approaches to setup ldap client

Hello,

I have a few ldap clients which were set up by my previous sys-admin.

1. In some of the servers I see that the configuration is done in /etc/pam_ldap.conf, /etc/nslcd.conf and there is a nslcd process running on the clients.

2. On other servers I find that there is only an /etc/ldap.conf and there are no nslcd process running.

The configuration values in both the approaches are the same.

Are there two different ways to setup an ldap client. I would like to understand both these approaches. In the second approach is there some other process which does the ldap lookup?

Can someone share links to docs related to both the installation steps.

Thanks