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
