[HECnet] DECrepeater 900TM

[Paul Koning]

Actually, switches (bridges -- same thing, just a different marketing
name) came way earlier.   The first bridges showed up fairly soon after
Ethernet first shipped.   I think the first one was the Vitalink bridge,
which would run over a satellite link (fairly slowly).   The first
full-speed bridge was the DECbridge-100 (two AUI ports) -- it
established the performance standard for bridges, full speed wire rate
min size packets all the time.   I don't remember when that product came
out -- perhaps 1984, maybe even a year or two earlier.

	paul

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On
Behalf Of jeep at scshome.net
Sent: Wednesday, October 28, 2009 11:57 AM
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] DECrepeater 900TM

Like Paul said it is a hub not a switch.   It was designed to be used
in
the DEChub-900 chassis or standalone.   It just preceded the Alpha
family of systems so was targeted at VAXen (10base-T) based systems.
Switches came afterwards.

-Steve

  _____

From: owner-hecnet at Update.UU.SE on behalf of Paul Koning
Sent: Wed 10/28/2009 11:31
To: hecnet at Update.UU.SE
Subject: RE: [HECnet] DECrepeater 900TM



I found a manual online:
http://www.carnagevisors.net/dec94mds/detmminb.pdf

It's a repeater (a.k.a., hub) not a switch (a.k.a., bridge).   It's not
fancy at all.   A repeater takes incoming Ethernet transmissions and
repeats them on all the other ports unconditionally.   Also, a repeater
is by definition a half duplex device, so you have the CSMA/CD
(collisions and all that) of classic Ethernet.   A bridge receives a
packet and transmits it on the appropriate output port (if any), and
can
be full duplex.

The 900TM is 10Base-T, so 10 Mb/s Ethernet -- not fast Ethernet
(100Base-T).   Suitable for old slow Ethernet devices...

              paul

-----Original Message-----
From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE]
On
Behalf Of Mark Wickens
Sent: Wednesday, October 28, 2009 11:22 AM
To: hecnet at Update.UU.SE
Subject: [HECnet] DECrepeater 900TM

Can someone explain to me what a decrepeater 900tm is? Is is a fancy
32
port 10MB switch?

Regards, Mark.
--