We are currently running Exchange 2003 in our organisation. We have four different routing groups/domains; UK, US, Asia and Canada. The routing groups are arranged in a hub-spoke method, with US being central and where external emails are sent/to.
We have implemented CAS servers only in UK, Canada and Asia, and are about to bring on Hub Transports in these three regions. The plan was to create more than one RGC for redundancy purposes and efficiency. The Exchange 2003 routing group in each region will have a RGC to the Exchange 2007 Routing group.
According to MS, we should disable minor link state updates across the org before installing a second RGC;
From what I can understand though, this will only be relevant once we have users on Exchange 2007 mailbox servers? Or even if we still have all users on 2003 Mailbox servers, do we still need to disable link state across the board? If so, why?