Retro networking / WAN communities

[Grant Taylor]

On 4/11/22 11:38 PM, Wayne S wrote:
> In the beginning there was thick ethernet limited to 100 m.

Um....

I *REALLY* thought the 5 & 2 in 10Base5 and 10Base2 was the number of 
hundreds of meters that the cable segment could exist on it's own.

My understanding is that the 100 meter limit came about with 10Base-T.

> 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.

I feel like even only 100 meters / 300(+) feet gives quite a bit of 
flexibility to connect multiple floors.  Especially if you consider the 
AUI drop cable.

Aside:  I'm not sure how long an AUI drop cable could be.  I'm 
anticipating between single and low double digit feet.

> 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.

Yep, the 3, 4, 5, rule.  Up to five segments of cable with four 
repeaters and stations on no more than three of the 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.

Didn't repeaters operate in the analog domain?  Meaning that they would 
also repeat ~> amplify any noise / distortion too?

Conversely bridges operated in the digital domain.  Meaning that they 
received an Ethernet frame and then re-generated and transmitted a new 
pristine Ethernet frame?

> 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.

I would say "network" as opposed to "segment" because a network could 
consist of multiple segments.

But otherwise I agree.

> 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.

Hum....

I can see problems with having enough actual taps on a network segment 
to connect all the machines in a given area with AUI drop cable length 
issues.

But I know that multi-port taps were a thing.  I've read about them and 
seen pictures of them for sale.  I think I've read about a singular tap 
that had eight AUI ports on it.  I've seen pictures of four AUI ports on 
a single tap.

So ... the idea of having too many multi-port taps to be able to connect 
machines in proximity seems ... questionable to me.  Single port taps, 
maybe.

> 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.

I feel like a hub is the 10Base-T evolution of a multi-AUI port tap.

> 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.

I feel like the switch and the bridge are doing the same thing from a 
learning / forwarding / blocking perspective.

I don't know which came first, but I suspect it was bridges.

> So each device was really an evolution to solve a problem of congestion 
> and ethernet length.

Sure.



-- 
Grant. . . .
unix || die