Random Partitioner (RP) is a scheme to organize how to place the keys in the Cassandra cluster node ring. This in turn impacts how information is spread across the cluster and impacts range query efficiency. Random partitioning will spread keys fairly evenly across the cluster.
The scheme is to use a BigInteger token and MD5 hash to determine placement.
This is the default partitioner.
Partitioning cannot change without serious impact to data, and so it does not change after setting with the initial configuration.
There are other partitions schemes such as Order Preserving Partitioning (OPP), Collating Order Preserving Partitioning and Byte-Ordered Partitioning.