RE: Basic CAT5 Network Question

["Paul Gordon" <paul@xxxxxxxxxxxxxxxxxxxxx>]

Many (most?) modern switches now have auto-detection for MDI/MDI-X (aka
straight/crossover) on all ports, so that you can use any port as an
uplink, with either kind of cable - you just plug any old cable(*) into any
old port, and it will just work... :-)  (*provided the cable is wired
correctly as one type or the other)

Failing that, you may have a specific port on one of your devices that is
set aside for that purpose, - it will usually be labelled as an
"uplink" port, or as "MDI-X" in which case, use that
port. - Check the specific device as well though to check whether this port
is "shared" with the one adjacent to it.. - often a so-called
8-port switch will actually have a 9th port labelled as the uplink/MDI-X
port, invariably this port shares the same internal connection as port 8
next to it, and you can only use ONE of them, not both together...

The important point to remember is that both ports _and_ cables can be
configured with crossovers in them, and to link 2 switches together there
should only be *exactly one* crossover between them. The crossover in
question is referring to swapping over the TX & RX lines so that TX
pins on one switch are connected to the RX pins on the other, and
vice-versa. Thus if you use a dedicated uplink or MDI-X port on one of the
switches, the crossover is in that port, so you should use a
straight-through cable and an "ordinary" port on the other
switch. If you use an "ordinary" port on both switches, then you
should use a crossover cable. Here's where it gets fun... if you use an
uplink or MDI-X port on *both* switches, then you should again use a
crossover cable! - but if you have auto-detection on at least one of the
switches, then you should be able to use either kind of port on the other
switch, and either kind of cable, and the auto-sensing port will work out
how to configure itself....

The maximum length each individual CAT5 cable can be is 100m (328ft). The
total length of connection (across directly connected hubs) must not exceed
205m (672ft). Strictly speaking, fast ethernet rules only allow two
"repeater devices" in the network, but I've blatantly ignored
this rule for years and never yet suffered any problems because of it...

HTH

Paul G.


________________________________

From: ukha_d@xxxxxxx on behalf of Danny Dawson
Sent: Wed 25/01/2006 22:50
To: UKHA_D Group
Subject: RE: [ukha_d] Basic CAT5 Network Question



It depends wat switches you have, try connecting them with a straight
through cable first either on the first or last port
If you cant see it on the other switch then try a crossover.
Danny


>From: "flidgetuk2002" <neil@xxxxxxx>
>Reply-To: ukha_d@xxxxxxx
>To: ukha_d@xxxxxxx
>Subject: [ukha_d] Basic CAT5 Network Question
>Date: Wed, 25 Jan 2006 22:09:47 -0000
>
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>
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>I'm moving my network switch (and servers) into a server rack in the
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>garage and I was wondering if I could take a CAT5 cable through the
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>wall into the study and then plug in another switch to give me more
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>connections in the study.
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>This would be rack switch to one CAT5 Cable then another switch (in
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>the study) then many CAT5 cables to printer/desktops etc.
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>Cross-over cable keeps jumping to mind, but I'm not sure in what
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>context. Can anyone help?
>
<SNIP>