Distribution Link Tracking service is used to keep track of file links eg: Shell shortcuts . DLT uses AD to store the link information and consists of client and server service due to which the AD database size grows.
Administrators should delete these DLT objects over time to reduce the AD database size and replication traffic. Microsoft has written a vbs script to perform the same which you can access from the below link
By default the batch file will delete 1000 objects with the span of 15 minutes, but if you have 100000 objects you would end up spending hours.
You can use -b option to specify the objects and the time for eg;
dltpurge.vbs -s server -d distinguishedname dc=domainname,dc=companyname,dc=org -b 13000 15