Retro networking / WAN communities

[Wayne S]

Some info for you guys from an old timer. In the beginning there was thick ethernet limited to 100 m. People wanted computers that were on different floors  connected together between floors and buildings.  That exceeded the 100 meter spec so the repeater was born to connect two 100 m thick ethernet seqments. A repeater was basically a signal booster between two ethernet segments. As you added segments interference and collisions became a problem as traffic on one segment was passed to all the other connected segments. Hence the bridge was born. It had some intelligence And didn’t pass packets intended for computers on its own segment to the other segments thereby reducing congestion and collisions. Then the router was born to connect multiple segments together at one point. And it had intelligence to determine what segment a packet should go to and  route it there. It also prevented packets from going onto segments that didn’t have the packet’s intended target thereby reducing congestion.
Hubs were born approximately the same time to get over the ethernet tap distance because by this time there were more computers in the single area that needed to be connected together to the Ethernet. Hubs were dumb so every packet that hit them was forwarded to every other computer connected to the hub into the segment the hub was connected to, so, for a segment that had a lot of computers, there was congestion and collisions. The switch came about. It was a smart hub that had intelligence. It could filter out packets that were not intended for other computers connected to it thereby reducing congestion.
So each device was really an evolution to solve a problem of congestion and ethernet length.



Sent from my iPhone

> On Apr 11, 2022, at 21:56, Grant Taylor via cctalk <cctalk at classiccmp.org> wrote:
> 
> On 4/11/22 9:55 PM, Tony Duell via cctalk wrote:
>> I am not sure what the actual distinction is, but a 'managed bridge' turned up at the local antique market (!) some weeks back. It has a pair of AUI ports and from the amount of logic/processor power inside it does a lot more than just pass packets from one port to the other,
> 
> Would you be willing to share pictures?
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>> The main board contains a pair of ethernet interfaces (AM7990 based), a 68020 processor, ROM, RAM, etc. A board on top of of it called the 'FLUT' (Frame Look Up Table?) contains a CY7C901 (16 bit slice ALU -- think of it as 4 off 2901 + carry loglc), a 29C10 seqencer, etc
> 
> Hum....
> 
>> After removing the leaking NiCd from the mainboard and repairing the corroded tracks it powers up and passes the self-tests. No idea what I'll use it for, but...
> 
> That seems like it would be an interesting piece of networking history to own.  If you're into that sort of thing.  ;-)
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> 
> 
> -- 
> Grant. . . .
> unix || die