To migrate from Live Communications Server to Office Communications Server 2007 R2, first you deploy the Office Communications Server 2007 R2 Edge Servers and Directors, and then you deploy the initial Office Communications Server 2007 R2 pool. Office Communications Server 2007 R2 Edge Servers can support a Live Communications Server pool, but Live Communications Server 2005 Access Proxy cannot support the new Office Communications Server 2007 R2 pool.

If you do not need external or remote access, but you do use Communicator Web Access, you can move users as soon as the Communicator Web Access (2007 R2 release) is deployed and configured.

If you need to preserve remote or external access for your users, first you replace your Live Communications Server 2005 Access Proxy server with the Office Communications Server 2007 R2 Edge Server. After the Office Communications Server 2007 R2 Edge Server is in place, deploy the first Office Communications Server 2007 R2 pool, followed by Communicator Web Access (2007 R2 release). You move users only when the full environment required to support external or remote access is in place.

Migration from Live Communications Server to Office Communications Server 2007 R2 follows this sequence:

These phases are described in more detail in the following sections.