Age-old ethernet equipment

From: Iggy Drougge <>
Date: Wed Mar 28 23:39:24 2001

Pete Turnbull skrev:

>On Mar 28, 2:47, Iggy Drougge wrote:

>> This weekend, along with a batch of PS/2s, I received a 3Com 3c588 1988
>> vintage MultiConnect Repeater. It's a 19" case with space for sixteen
>> Mine features one card indicating power with a green LED as well as a
>> female connector, then fourteen cards equipped with a BNC connector, an
>> activity led, one partition LED and a partition/reset switch each.
>> Whenever a card is connected to a 10b2 network, the partition light
>> otherwise emits a steady red light) begins to flicker. Upon flicking the
>> switch into reset mode, the partition light goes out. The network works
>> as long as there is no partitioning. I suppose its purpose is to not leak
>> traffic between several networks.

>Not quite. "Partitioning" is network jargon for disconnecting a port or
>segment. If there's no terminator, the transceiver will behave as though
>continually detecting collisions, and the repeater will automatically
>disconnect ("partition") that transceiver from the rest. The red LED
>lights up to tell you it has done so. It won't self-reset because if it
>really were connected to a faulty network segment, it might end up going in
>and out of operation.

I see. I really must create a lot of small networks now, so that I may
saturate all those ports.

>> What is the purpose of the DB-9 connector?

>I'm not familiar with this particular repeater, but I imagine it's a serial
>port for management and setup. Modern 3Com equipment has a serial port
>wired to the same (non)standard as PC 9-pin ports, but that one may not be
>wired in the normal way. It may also do auto-baud-rate detection, and it
>probably won't emit anything until it receives a couple of carriage
>returns. My old SynOptics 2813 hubs have a DA9 as well, and it's some odd
>connection for a modem (they also have a DB25 whichj is a normal serial

What management would be involved with a repeater? All other hubs and
repeaters I've used have been entirely automatic.

>I'd pull the card and see if anything on it gives you any clues.

>> Could this repeater slow a network down?

>Unlikely. You can get different cards for those repeaters -- 10baseT,
>10base2, 10base5/AUI, and the 10baseT cards have 3 ports each. 3Com
>wouldn't have done that if it were going to significantly impact bandwidth.
> It's basically just a buffer; it doesn't process the data passing through
>like a switch does. Any intelligence in it is just for monitoring and
>setup (partitioning, etc).

I'd think so too, but I heard on Usenet that old repeaters (the kind which
actually call themselves repeaters =) could slow down modern networks. Don't
ask me how, though.

>Another thing you could try is snooping on the network packets (if you have
>snoop, tcpdump, or similar) to see if the repeater emits any packets when
>it first powers up. It might be trying to BOOTP to get an IP address, and
>if you give it one, you can probably telnet to it and look at the setup.
> It probably needs a password, though.

My, that's interesting. I'll let the OpenBSD machine have a go, then.

>> What does partitioning actually entail?

>See above. Some more modern 3Com hubs also have the capability to split
>the unit into segments (eg, the SuperStack II PS 40 hubs and others can
>have 4 segments) but assigning ports to different segments isn't usually
>called partitioning.

IOW it's just a glorified OFF switch. =)

En ligne avec Thor 2.6a.
Hackers do it with fewer instructions.
Received on Wed Mar 28 2001 - 23:39:24 BST

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