Token Ring Networking as a protocol/concept (not so much physical IBM hardware, of course) rather than CSMA/CD. It naturally makes sense that allocating BW via

Token Ring Networking as a protocol/concept (not so much physical IBM hardware, of course) rather than CSMA/CD. It naturally makes sense that allocating BW via a token would be much more power efficient and faster than transmitting into the void and hoping for no collision. Its hard to get line rate traffic with CSMA/CD but the financial services co I was working at back then had very high util in the upper 90%s for hours. I also miss ATM and its complicated and semi-obscure adaptation layers, pretty cool although toward its death it was just a weird way to send pt-to-pt ethernet frames. ISDN was like that too, a whole protocol stack, pretty interesting exciting ideas, toward the end it was just a 128K pt-pt interface for internet access and of course a voice trunk signalling protocol replacing old E+M signalling. Both could have been interesting/cool. X.25 switching never really took off either.