What was a Token Ring network? (dfarq.homeip.net)

[1] https://www.youtube.com/watch?v=R18APaR7mTQ at 28:54.

In comparison to that, traditional ethernet (think concentric cabling and terminators) glitched often and one flaky part of a cable could ruin your day.

ARCNET was much slower in theory, but robust, fair and stable and did not totally die under load from a single client.

Fast-forward to 2013, when my wife was giving birth to our daughter in one of their hospitals, and I noticed an unused type-1 token ring wall jack in our room right beside some occupied 8P8C (aka RJ-45) jacks.

Fun fact: each system had an IN and an OUT coax port, and the coax cable was about as thick as a thumb. If a system died, a small hardware box short circuited, tying the IN and OUT coaxes together. This kept the ring intact, but it would also make that segment of the network longer and there were strict distance limitations between nodes. If the distance got too big, the entire ring broke. Also, if any coax cable got damaged, that also lead to a ring break. Prime had a special diagnostic program they could use on multiple nodes to try to find ring breaks.

It didn't last. Gigabit Ethernet began popping up around the time of the dot-com bubble bursting. That was it for Token Ring.

Token Ring was a networking alternative to Ethernet.

With Ethernet when a node wants to transmit it just does so, then backs off and retries if there was a collision (someone else trying to transmit at the same time).

Token Ring avoided collisions by passing a "permission to transmit" token from node to node in circular (ring) fashion.

Essentially that was the same for Ethernet too, everything on the same leg needs to talk at the same speed, though IIRC a different speed device wouldn't take down everything, it would just cause a significant excess of collisions due to the out-of-sync cross-talk and not be able to talk to anything itself. It wasn't until switching hubs and full switches were around that you could mix speeds on the same leg (with a switching hub you'd actually have two legs, one at each speed, bridged, with a full switch you have a separate collision domain per port so can mix speeds quite freely).

In principle, token ring was faster than Ethernet (which was CSMA/CD in the day): the mathematics of token ring were exact and analytic, and, when solved, gave higher speeds and better reliability than Ethernet, the mathematics of which were so complex (think three-body-problem) that analytic solutions were available only for bounding equations, which resolved to slower than token ring.

In practice, Ethernet was much faster.

A classic "the model is not the territory" problem.

I don’t disbelieve the author here but anecdotally the only time I’ve worked with coax BNC plugs for networking is with TR. And it be never seen a TR network in the wild that wasn’t coax.

It’s interesting to read that other cable types existed for TR.

That textbook was sort of system textbook which describes a lot of low level stuffs such as networking, hard disks and such.

In fact, broadcast ethernet is essentially token ring, except instead of a token it just grabs the wire. Only one machine can grab the wire at a time. Switches hide that from most people.

IBM were still using them in 2004.

https://youtu.be/4UWibKEjyY8?is=rpvYv31UIB3DLIep

https://en.wikipedia.org/wiki/Vampire_tap

Lot more details: https://en.wikipedia.org/wiki/Token_Ring

The main reason Ethernet won the war was because it was cheaper.

He should have stopped there. That was it. And because it was cheaper, less complicated to build the chips, 'good enough' networking, a bunch of folks jumped on the bandwagon. And here we are.

If you had a 16 megabit network and brought up a system at 4 megabits, it took down the whole network.

Well, yes, everyone who has ever mentioned TR tells some variation of this. And if you left the terminator off of the coax ethernet, you brought the whole network down. But TR got smart MAUs and ethernet got UTP hubs around the same time and problem solved.

And hubs were a lot cheaper than smart MAUs. Sooo...

Ethernet was junk if you went with the cheapest options all around, but you could make it acceptable if you invested some of the savings in improved technology.

Just like TR. If you were deploying dirt cheap 8228s after 1990 or so, your network still sucked. You didn't do that.

But the other reason Ethernet won was because of scale.

Yes, there was a thing called 100Mb Token Ring. Someone might have even shipped some number of them. I never saw one in the wild, and I don't know anyone who claimed they had who didn't work for IBM or Madge (which, btw, wasn't an 'obscure' network company at the time and made more than just TR cards).

That's because basically everyone who did Token Ring (IBM most of all) had decided that you wanted to scale TR you were going to ATM (for a bunch of mostly political and marketing reasons). Which, unlike TR, was in reality a very bad idea, but that's another story.

I've never even heard anyone even suggest 128Mb Token Ring, and I suspect someones LLM is hallucinating. There was a gigabit Token Ring standard (IEEE 802.5v), but I feel pretty confident saying noone ever shipped it. Like I said...ATM was gonna be the future.

Ethernet used a 15-pin connector that looks quite a bit like a PC joystick connector. Token Ring used a 9-pin connector that looks like a 9-pin video connector or an Atari style joystick plug.

Ok...I'll just be snarky and point out there are ethernet cards that use a 9-pin D-sub connector to reuse a TR wiring physical plant. I have several.

Coax connectors for Token Ring did exist

Citation needed. I've seen coax for 802.4 industrial networking stuff, which is not TR. I'm betting more hallucinations.

ARCNET was another competitor from the same timeframe. It, too, was a contender for a while because it was backed by Datapoint, a pioneer in office automation using small computers.

Arcnet was a contender because it was even cheaper than ethernet and it was (and still is) widely used in industrial environments. And some popular early PC file sharing systems (e.g. LANTastic) would use Arcnet.

https://www.automatedlogic.com/en/media/AAR_CS-aug2023_tcm70...