[geeks] Re : Seeking network direction box with many 15 pins

[Bertrand Hutin]

the box with many 15 pins connectors was a Hub.
It should have been connected itself to a transceiver on a thick ethernet
cable or
may be a thin one (BNC connectors)

the weird problems may be linked to autonegociation problems.

--- En date deB : Mer 17.9.08, Joshua Boyd <jdboyd at jdboyd.net> a C)critB :
De: Joshua Boyd <jdboyd at jdboyd.net>
Objet: [geeks] Seeking network direction.
C: "The Geeks List" <geeks at sunhelp.org>
Date: Mercredi 17 Septembre 2008, 4h38

I'm trying to understand somethings about how ethernet works.  I
would be happy for either answers, or pointers to free resources
containing the answers would be even better.

When I plug an ethernet device into an ethernet switch/network, what
happens below the IP level?

I was talking to someone with a weird problem.  His device would talk
to his PC when connected via cross-over.  When both were plugged into
a Cisco 2900 switch, communications between the devices would work,
but the show-mac-addresses (or whatever the specific command is
because I'm not a cisco guy) wouldn't show the device's MAC, but
the
LEDs showed a connection was made.  When plugged into a Cisco 3550, a
connection was shown, but no communications happened between any
other PC and the device.

I know that ARP used to map IP addresses to MAC addresses (data link
layer addresses), and I know that MAC addresses are to uniquely
identify devices on an ethernet network and I know about ethernet
frame sizes, but I know nothing else about ethernet and how devices
negotiate.  Is this what the spanning tree protocol does?

Also, what is the relationship between AUI, AAUI, MII, and the phy
chip on a embedded design that seems to say it speaks MII?  Also, I
seem to recall once setting up a box with a lot of 15 pin connectors
on it.  I believe a AUI adapter went on one of these to connect this
box to a Cat5 switch, while the other 15 pin connectors were
connected via 15 pin cables directly to an Onyx, a Sun 4/330, and a
few IPC/IPX machines.  What was that thing?  It was considered
somewhat out dated when I was touching it in the 1996ish time range.
I think it was referred to as a thicknet hub.

Anyway, I've been flipping through wikipedia and google, but I don't
feel I've found the answers to these questions.  It isn't essential
that I find them, but I don't like knowing there are things out there
related to what I work on that I know so little about.
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