6.3 Connecting routing groups

An Exchange 2000 Routing Group is a collection of Exchange servers joined by a persistent network connection that has relatively low-latency and is within a single network hop of the routing group master. Within a Routing Group, SMTP messages are sent directly from one server to another. Messages sent between Routing Groups are sent to a bridgehead server in the recipient s Routing Group.

All information about routing groups and connectors is stored in the Windows 2000 Active Directory configuration-naming context. The configuration-naming context is replicated to all domain controllers in the Active Directory forest, which means that all Exchange routing information is known to all Exchange servers in the organization. However, you must still configure connections between routing groups. If you change the underlying network infrastructure by adding new network links, the Exchange routing topology must also change to take advantage of the modified network.

Exchange 2000 routing group boundaries should be based upon the availability and reliability of the underlying network bandwidth. Unlike Exchange 5.5 sites, communication between servers within the routing group is not based on synchronous RPCs, which required reliable, high-bandwidth, low-latency connections. Exchange 2000 servers in the same routing group communicate with each other using SMTP, which has less stringent requirements for network bandwidths and latencies. Perhaps the most important factor for determining routing group boundaries is the stability of the network connection, rather than high bandwidth. You should place servers in separate routing groups if the network connection between the servers...