difference between referral, glue and chain

["Eudes LEDUCQ" <LEDUCQ@hec.fr>]

Hi,
 
My question is simply. I have two openLdap directories A et B both
work
with an Berkeley DB. There are strictly different. I have a subtree in
the second directory what I want to add to the second directory.
 
I know that it's possible to create a referral link between the two
directories. But when I use a referral link , It's need what the user
use to connect be on the both directories, like
cn=Manager,dc=monAnnuaire,dc=fr (A) and cn=Manager,dc=monAnnuaire,dc=fr
(B). 
 
But it's not my case. I have cn=Manager,dc=monAnnuaire,dc=fr (A) and
cn=Manager,dc=user,o=directory,dc=en (A).
 
I have a problem with the user not found. I need to re entrer the
second user manually (and refeeral work fine). So I search an over way
to link my two directories without need to re entrer user/password.
 
it seam to be possible to chain openLdap directories  or glue ?

is some one can explain me in what chain or glue consist of ?  and how
I can do it with openLdap ?

Thx
 
E Leducq