When multiple paths exist to a destination, Exchange Server 2007 Routing uses deterministic algorithms to choose one of the paths. The algorithms are deterministic because one of the paths is always chosen (as long as the contributing factors do not change). This article describes the AD Site and Connector Selection algorithms used by Routing.
Read at source http://msexchangeteam.com/archive/2006/09/14/428920.aspx
Technorati : AD, Exchange 2007, Sites and Services
Del.icio.us : AD, Exchange 2007, Sites and Services