Hello Ashley,
Cisco does not sell LDAP servers. Cisco sells an authentication product like ACS that helps authenticate against LDAP or windows AD servers.
CUCM is Cisco unified call manager that is a software based PBX used for IP telephony. All phones would register with that server and would get extensions, dial plan , call routing etc.
Hope this helps.
Regards/Durga Prasad
Sent from Cisco Technical Support iPad App