Our organization is about to upgrade to Exchange 2010 from 2003. We are about ready to install the CAS/HT role and will therefore need to suppress link state updtaes as recommended. However, our management wants to set the registry key across the organization over the course of a few days. We have many Exchange servers, some stand-alone, others clustered. Will this be a problem for Exchange 2003? Do we need to suppress link state updates in one shot for it to work?

“If multiple paths exist between the Exchange 2010 routing group and any Exchange 2003 routing group, minor link state updates must be suppressed to make sure that message looping doesn't occur when a route is recalculated.” ---------Refer to <Upgrade from Exchange 2003 Transport> “The first routing group connector is created when the first Hub Transport server role is installed on a computer in the Exchange organization. Before you create additional routing group connectors, perform this procedure on every Exchange 2003 server in the organization” ---------Refer to <Suppress Link State Updates> You just need to suppress the link state updates before create additional RGC between exchange 2003 RG and exchange 2010 RG James Luo TechNet Subscriber Support in forum If you have any feedback on our support, please contact tngfb@microsoft.com Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.