The Heart of Lotus Notes Replication is really hard.
Notes does that nobody else knows how to do yet.
Replication, the method used by Lotus Notes to synchronize databases, is an essential aspect of the popularity of Lotus Notes. This chapter describes the concept of replication and the different methods used for effective replication. In this design, all spoke servers replicate with the hub server and not with each other. The hub server can be considered to contain the master copies of each database. The reduced network overhead with hub replication is significant, because the alternative of allowing each spoke server to replicate with every other server creates significant additional traffic when there are a large number of Notes servers.