Actually to complete the story, MFEnet preceded HEPnet & SPAN as DEC was
still developing the DECnet protocol at the time. When Sid put together
the proposal for SDSC, it was a clone of the operating and successful
MFE Computer Center (down to the floor plans of the building). The CTSS
operating system for the Cray at that time included the MFEnet protocol.
In that same time frame the MFEnet itself was running out of address
space and worked through a transition to TCP by running MFEnet over IP.