The Replication Server at each primary or replicate site coordinates data replication activities for local data servers and exchanges data with Replication Servers at other sites.
Receiving transactions from primary databases through a Replication Agent and distributing them to replicate database sites that have subscriptions for the data
Receiving transactions from other Replication Servers and applying them to local replicate databases or forwarding them to other replication servers that have subscriptions for the data
Receiving requests for data updates from a replicate database and applies them to a primary database
The information needed to accomplish these tasks is stored in Replication Server system tables that are stored in the Replication Server System Database.
See Replication Server Administration Guide Volume 2 > Performance Tuning > Replication Server Internal Processing for more information about the internal elements of the Replication Server.