Some time ago, The decision was taken by my corporation to shift to Single Domain AD Windows 2003 R2) model rather than the current multiple, parent child domains spanned across various eographical locations connected via VSAT/leased lines.

What will precede Single domain would be a Global WAN where one service provider will likely manage MPLS links across various office sites. The dedicated bandwidth will vary from 512K to 2mbps.

My recent concern is to think about designing an IP Schema for all locations spanning across UK/Gulf/Asian countries.

Some IT guys are of the opinion that we would assign IP addresses from the current pool at each location to the new servers and undertake migration. I feel that re-designing the whole IP Schema would be a better idea because the current one is very haphazard and and has evolved over time.

While I push for a new design, I need to take of security issues and future scalability at each location.

What all factors should I incorporate in my IP design in this scenario? Is there anything I have to take into consideration vis a vis MPLS backbone?

Does anyone has any experience in designing an IP schema for such a project?

All advise is welcome.