Basic UID= question

[TL]

I noticed in my ldap, that my uid is unique only in its branch.. is this 
correct? how can i fix the configuration to make it unique in the whole tree 
?
uid=user1,ou=Mua,ou=People,dc=xxxx,dc=net, same uid i can copy to different 
branches for example to uid=user1,ou=People,dc=xxxx,dc=net
Thnxs in adv.