SimpleSnitch 

The SimpleSnitch is used only for single-datacenter deployments.

The SimpleSnitch (default) is used only for single-datacenter deployments. It does not recognize datacenter or rack information and can be used only for single-datacenter deployments or single-zone in public clouds. It treats strategy order as proximity, which can improve cache locality when disabling read repair.

Using a SimpleSnitch, you define the keyspace to use SimpleStrategy and specify a replication factor.