If LDAP uses the configuration shown in Configuring Combined Identity Map and Identity Search to process a username in DN form, for example:
cn=dl160010,ou=northamerica,ou=user accounts,dc=td,dc=teradata,dc=com
the search does not use a filter because every filter excludes the equal sign characters in the DN, and as a result, the search finds no matches and uses the username without change.
The Configuring Combined Identity Map and Identity Search example does not work in the corp environment because the two trees, dc=newyork,dc=corp,dc=com and dc=div,dc=corp,dc=com exist in separate directory environments. For this kind of configuration to work, the trees must be managed by the same directory service.
The ${0} in the second configured identity search refers to the entire username (authcid) string. Since the search pattern enforces the naming convention that is in both the DIV and NEWYORK domains for the userPrincipalName attribute, the authcid is adequate.