[124960] in North American Network Operators' Group
Re: Hubs on a NIC (was:Re: what about 48 bits?)
daemon@ATHENA.MIT.EDU (Steven Bellovin)
Wed Apr 7 23:32:33 2010
From: Steven Bellovin <smb@cs.columbia.edu>
In-Reply-To: <201004071503.o37F3HPI030585@aurora.sol.net>
Date: Wed, 7 Apr 2010 21:00:00 -0400
To: Joe Greco <jgreco@ns.sol.net>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Apr 7, 2010, at 11:03 16AM, Joe Greco wrote:
>> On Wednesday 07 April 2010 07:18:57 am Joe Greco wrote:
>>> To me, this is a Dilbert-class engineering failure. I would imagine =
that
>>> if you could implement a hub on the network card, the same chip(s) =
would
>>> work in an external tin can with a separate power supply. Designing =
a
>>> product that actually exhibits a worse failure mode than 10base2 is =
...
>>> strange to me.
>>=20
>> I have in my gear museum a fairly large box with a couple of this =
type of 'hub=20
>> on a card' installed. And in this particular case, it made perfect =
sense, as=20
>> the box is an Evergreen Systems CAPserver, and has 16 486 =
single-board=20
>> computers tied to two 8-port hub cards (two ports on each modular =
plug, too),=20
>> with....wait for it... a 10Base-2 uplink. These were used mostly for =
remote=20
>> network access and remote desktop access.
>>=20
>> If you want more data on this old and odd box, see=20
>> http://www.bomara.com/Eversys/capserver2300.htm
>>=20
>> I can see a hub card being useful in an old NetWare server setting, =
though,=20
>> since if the server went down you might as well not have a network in =
the first=20
>> place, in that use case.
>=20
> Certainly. I can come up with a bunch of reasonable-use scenarios =
too,
> but most of the people here will have run into that awful situation =
where
> a product is used in a manner that isn't "Recommended".
>=20
> In this case, I know that some of these cards were marketed in the =
same
> manner that workgroup hubs/switches are marketed; you would =
daisy-chain
> these stupid things so that your PC would feed the cubes right around =
you
> and then have an uplink and downlink a few cubes to the next "hub".
When I had the need to wire a building around 1987, I opted for the =
multiport 10Base5 repeaters that DEC made -- they were called DELUAs, I =
think. I'd had quite enough of distributed single points of failure, =
thank you.
>=20
> Remember, it was this strange time when people were uncertain about =
how=20
> networks were going to evolve, and what the next thing would be, and
> even then, 10baseT was being deployed over Cat3 (sometimes recycled/
> repurposed), so any sort of "enabling" gadget such as these cards had =
a
> tendency to be abused in various ways.
Right -- the wire and pin assignments for 10BaseT and 100BaseT were =
designed to permit sharing the cable between Ethernet and phone.
>=20
> Two ports on each modular plug, though.... (shudder) ;-)
>=20
Hey, I had that in my house on my 100BaseT network, till I upgraded to =
gigE and had to give in and buy another switch. (Sigh -- home network =
configurations of NANOGers. I'm contemplating putting in VLANs now...)
--Steve Bellovin, http://www.cs.columbia.edu/~smb
