I need input from field pros that have Active Directory installations of 50,000 plus users internationally in a Single Domain. Please, no Microsoft bashing by Novell disciples or Promo talk by MS disciples. I don?t need product info as I am a reasonably experienced CNE/MCSE. My situation is this: IT organization about to migrate to AD using a Single Domain and Exchange 2000. IT constitutes a small number compared with the 3500+ LAN Administrators who work in the prospective businesses. IT plans to manage 50,000+ W2K Pro desktops with Intelli-Mirror and none of the business-lines will have Admin rights. I advised the staff in our business-line to fight for our own Domains within the single forest which IT has Domain Admin rights. They believe larger companies use AD in 1 Domain without problems. I submitted the additional domains provide a replication cushion to ease tremors when other domains experienced earthquake and better performance. I know that a large multinational single domain is technically possible so I don?t need MS disciples tell me so. I also know this is MS?s first release and can?t be trouble free. Novell has developed their product for years and had their share of replication and DS problems. I give MS the benefit and assume they will solve problems and provide quality product in future but not the 1.0 release. I can download 100mb file from high capacity server across the planet in 3-5mins. so our bandwidth is good but a significant DS problem could bring us to a crawl. Professionals working in XLarge AD environments hear my cry and write back providing real examples of problems in areas of DDNS, replication, regular server reboots, etc..resulting in network downtime. I don?t believe anybody is fully using AD in a single domain 50,000+ user multi-national environment. Major bonus if you work for Texaco or other Trident Oil company.