They are emulation of replication ports.
RF is a fiber director converted to be an RDF port, it uses the fiber protocol.
RE is GigE so it uses TCIP and has an IP address assigned to it.
RA is remote adapter.
RDF ports are replication ports.
Remote adapter, RF, RE RA. They are all terms that describe the port that is used for array-to-array data replication using the SRDF replication technology. Think Disaster Recovery capability. Search SRDF in support.emc.com and take a look at the SRDF product guide to learn more on this technology.