There are many replication topologies. Some of them are the traditional master-slave replication, chain replication, master-master replication, multi-source replication, and so on.
Traditional replication involves a single master and multiple slaves.
Chain replication means one server replicates from another, which in turn replicates from another. The middle server is referred to as the relay master (master ---> relay master ---> slave).
This is mainly used when you want to set up replication between two data centers. ...