I have a few simple questions. Currently building the 2010 sp1 infrastructure. 2CAS/HT in NLB and 2 MBX in a DAG (all 2010). Old config still in use is 2 CAS/HT in HLB and 2 MBXs (no redundancy) and 1 Edge 2007. I re-subscribed the 2007 edge when I install the 2010 HT servers. My questions: Do I need to introduce Edge 2010 before mailboxes are moved to Exchange 2010? OR can Edge 2007 and Edge 2010 co-exist? Can edge 2007 handle all traffic for both 2007 and 2010 mailboxes?

If your routes are configured so that the Exchange 2007 hub transport servers are the ones that route to the edge transport server, then I'm pretty sure it won't make any difference. I honestly don't know if you should configure Exchange 2010 hub transport servers to send to an Exchange 2007 edge transport. I'd probably want to upgrade the edge server before switching the routing through the Exchange 2010 hub transport servers. Ed Crowley MVP "There are seldom good technological solutions to behavioral problems."

Makes sense. So many factors in this migration. Sometimes I just stop thinking properly. Thanks for the input! Much appreciated.