http://blogs.msdn.com/byrons/archive/2009/05/07/edge-planning-tool-for-office-communications-server-2007-r2.aspxThe following is a link for the R2 Edge planning tool; I highly recommend going through this planning wizard before you deploy your edge server(s). http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=ec4b960c-3fe2-41bd-abdf-ae89cfcb8c6en-USCommunityServer 2.1 SP1 (Build: 61025.2)