Domino Mail Routing delivers a message to a users home server. In the case of a clustered environment, this means that when Server A accepts mail for John Citizen, it Routes it to Server B (John's Home Server), but since Server A and Server B are cluster members, the message is then REPLICATED BACK to Server A.
It would be more efficient if Server A was able to understand that it is in a Cluster with Server B, that it has a Replica of John's mail file, and therefore when it receives a message for John it is delivered LOCALLY, and then Cluster-replicated to Server B, John's Home Server.
And if Server B is down - the message isn't waiting in Server A's mail.box for Server B to come back up, and since John's Notes client has already "Failed Over" to Server A, he receives the message immediately.
1 Network transaction instead of 2.
Better Cluster and Fail-over functionality.
Include a new field on the "Advanced" tab of the person document called "Replica Mail Servers", and "Mail Replica ID".
When the Catalogue task runs overnight, it does a quick check to see if the replica ID of a database is recorded in a person doc in the directory, if it is, then it updates the "Replica Mail Servers" field in the person document with the Local server's name.
If a server is a member of a cluster, it's Router task does an additional check when delivering Mail to "John Citizen" to see if it is listed in John's "Replica Mail Servers" and instead of routing the Message to Server B, it deriver's the message to the Local replica. Cluster replication then takes over to transfer the message to Server B.