While the SMB protocols are not limited to running on Token Ring, they are
usually thought of in conjunction with Token Ring. Because Apple SMB File
Transfer Utility works so closely with the Texas Instrument Token Ring
interface controller chip set on the TokenTalk NB Card, it would be
difficult to port to an Ethernet environment without a major rewrite of the
software.
For file transfer and sharing in a PC/Macintosh environment over Ethernet,
try an AppleTalk Filing Protocol Server solution, like Novell's NetWare or
even AppleShare.