Please correct me if I’m wrong, might have breathed in too many soap fumes.
Token Ring sends the packets to every node by passing it from one node and if that node is not the recipient it passes it on to the next node.
Memos were created the day before with a list of recipients then it was passed around till everyone on the list had read it.
That’s not how token ring worked. The token controls which node is allowed to transmit over a shared medium. Every node saw every packet and made it’s own determination of relevance.
That’s what I thought too unless the pic (left) literally is how cables are arranged??
My understanding was a shared medium (say, all computers in parallel on a single UTP), where they pass a virtual token “packet” that assigns the right to transmit while anyone receives if addressed, like a ball between kindergarteners sitting in a circle.
The pictured ring topology (left) makes it seem like everyone can only talk to a computer one over, which seems awful for efficiency and resilience, while the pictured star topology (right) introduces an authority figure (MAU is like a kindergarten teacher that decides who walks around and gives the ball to whichever child they think should speak next). Both seem inherently worse than Ethernet - left can be completely broken by disabling one or two nodes while the right one is just a switched network with less throughput.
I think token ring is a data link layer technology that controls transmission access over the physical connection. Like early non-switched Ethernet, computers are connected in parallel to the same wires but instead of collision detection and random delays, which caused congestion and serious overhead on busy networks, a “token” is passed around and determines the right to “speak”. Everyone listens at the same time and starts receiving packets when addressed. If the computers were literally wired in series like a looping daisy chain, the failure of one would destroy message propagation. Instead, if the token-bearing computer or disconnects from a token ring network, the token is presumed expired after a short while and a new token-bearer is chosen. It’s like a kindergarten activity where you sit around in a circle and need to hold the ball to speak, passing it around. It doesn’t matter who you’re addressing, you can even broadcast, but that’s handled by a higher-level protocol.
As for memos, I have never used them and they seem extremely inefficient.
Edit: looks like Token Ring is actually more physical than I thought, with special cables connecting computers in series, so you may be right. That sounds really stupid as a thing to build a network on, it’s easy to cut it in half by disabling just two computers, antithetical to the internet’s resiliency principle.
Edit edit: my original understanding was right, the literal cable ring is obsolete for good reason. I still don’t get the role of a MAU in the star topology unless it’s just needed for old NICs to understand virtual tokens.
My memory of token ring is vague, but I think it was originally a ring in series as you said - however token ring switches (that isn’t what they were called) also existed, which was the “modern” way of writing up a token ring network.
Yeah, see the pic in the thread. The “switch” (MAU, Media Access Unit) seems redundant to me though, based on what I read I would expect the network interface cards to create a functional ring on their own over a shared medium. Maybe the old cards for ring-topology networks only worked in that one mode and the MAU made them compatible by pretending they were part of a physical ring, cutting computers out of it if they turned off.
Yes, I think that’s probably how it worked.
😜 I love Cunningham’s law. Yeah token ring sucked hard we used it with bnc coax cables and vampire taps at school.
That is what ‘automation’ often is. You take a working process, then let machines do as many steps in that process as you can. Harvesting crops, sending memos, robots spraypainting car parts, self driving cars (We still have a lot to do there)
Building on that it gets even more interesting as we try to find better, or even completely new processes.
