On 4/12/22 11:41 AM, Paul Koning via cctalk wrote:
I don't know anything about the 3 Mb/s prototype other than that
it existed. When I speak of Ethernet and its "day 1" I mean 10 Mb/s
Ethernet as defined by the DEC/Intel/Xerox spec.
Okay. Fair enough.
I surmise that we're talking about Ethernet II a.k.a. the Digital /
Intel / Xerox that was commercialized.
Repeaters are a core part of that spec, and they were among the first
wave of products delivered by DEC.
I can see how the need for repeaters was learned during Ethernet
research at Xerox PARC and incorporated into Ethernet II / DIX from the
start.
I no longer remember. That's possible, or perhaps they were a number
of small segments each with a handful of stations on them.
That would make /some/ sense. E.g. have a 10Base2 segment for a set of
cubicles and then link the multiple segments together with a multi-port
bridge.
That's true but only part of the story. For one thing, as I said,
both mechanisms were part of bridges from the start (at least from
the start of DEC's bridges, which may not be quite the very earliest
ever but certainly are the earliest significant ones).
Fair enough.
The learning part of bridging is actually the hard part. ...
I feel like the conceptual algorithm / logic is simple. I concede that
implementing it within timing requirements could be non-trivial ~>
difficult.
Spanning tree is indeed another algorithm / protocol, but it's a
control plane algorithm with relatively easy time constraints, so
it's just SMOP.
I guess I always assumed that spanning tree came along /after/ and / or
/independently/ of bridging / switching.
After all, the BPDU in spanning tree is "Bridge ..." so that name tends
to imply to me that it came about /after/ bridges were a thing on at
least some level.
That rings a bell. Someone reminded me of 100Base-T4.
T4 rings a bell for me. -- It reminds me of some references to T2 and
T8. It seems as if there was great conflation between the number being
reference to wires; 4 vs 8, and pairs; 2 vs 4, respectively.
In any case, there were two proposed, one that made it. The other
might have gone as far as one or two shipping products, but no further
than that.
Yep.
--
Grant. . . .
unix || die
