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Hi,

Is 100Base-TX a switch or hub?
I think it supports either half-duplex or full-duplex mode. Then, the
duplex modes are related to the switch or hub functionality somehow ?
That is, if it functiona as a switch, it should run in full duplex
mode, or if it functions as a hub, it should run in hal-duplex mode.

Thanks you so much.

Min

minseokoh@hanafos.com wrote:

Hi,

Is 100Base-TX a switch or hub?
I think it supports either half-duplex or full-duplex mode. Then, the
duplex modes are related to the switch or hub functionality somehow ?
That is, if it functiona as a switch, it should run in full duplex
mode, or if it functions as a hub, it should run in hal-duplex mode.

Thanks you so much.

I'm not sure I understand your question. 100TX can use either a switch or a
hub--with a hub it's half-duplex, with a switch it should be full.
Connecting only two computers it doesn't need to use either, just a
crossover cable.

Min

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)

minseokoh@hanafos.com wrote:

Is 100Base-TX a switch or hub?
I think it supports either half-duplex or full-duplex mode. Then, the
duplex modes are related to the switch or hub functionality somehow ?
That is, if it functiona as a switch, it should run in full duplex
mode, or if it functions as a hub, it should run in hal-duplex mode.

It's neither. 100baseTX is an ethernet specification, that may be used with
switches, hubs and NICs. It can also be full or half duplex.

Hubs are half duplex and switches can be operated in full duplex.

A "hub" is a device that operates only at the physical (eg electrical)
layer - another term for a hub is a multi-port repeater. It does not
traffic isolation - basically, it makes things look like every node in
the network is on the same piece of wire.

A "switch" is a device that operates at the data-link layer - another
term for a switch is a multi-port bridge. A switch can do traffic
isolation - learning which MAC addresses are associated with which
ports on the switch and then only sending traffic to those MAC
addresses on the associated port(s).

rick jones
--
firebug n, the idiot who tosses a lit cigarette out his car window
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

In article <1131854890.637564.299820@g44g2000cwa.googlegroups.com>,
<minseokoh@hanafos.com> wrote:

Sorry for the confusion. Yeah, right. I meant for the central device
conforming to 100Base-TX spec.
I wanted to make sure if it can function as either a hub or switch and
if so, when it runs as a hub, the communciation mode must always be in
half-duplex, and when it runs as a switch, it must always be in
full-duplex.

No, you have the wrong emphasis.

Any given communications device might be a hub, switch, or router.
If it is a hub, then due to the definition of what hubs are,
then the device -must- communicate in half duplex. Switches
and routers can use full duplex or half duplex independantly for
each link.

Putting any given device into half duplex mode will not make it a hub,
and these days very few devices that are running in half duplex mode
are hubs. (These days, it's mostly printers that run half duplex...
since they seldom need to communicate much back towards the hosts.)

The concepts of hubs and switches and routers are independant of
100Base-TX.
--
All is vanity. -- Ecclesiastes

One more thing, for switch configuration, can the half-duplex mode not
be supported? I don't see why not.

Thank you.

Min

Thanks for all the replys.

Sorry for the confusion. Yeah, right. I meant for the central device
conforming to 100Base-TX spec.
I wanted to make sure if it can function as either a hub or switch and
if so, when it runs as a hub, the communciation mode must always be in
half-duplex, and when it runs as a switch, it must always be in
full-duplex.

From the replys, I guess my pressumption must be correct.
If I still understand the system incorrect, please let me know.

Thank you so much, everybody.

Min

minseokoh@hanafos.com wrote:

One more thing, for switch configuration, can the half-duplex mode not
be supported? I don't see why not.

When an ethernet device is connected, it autonegotiates with the device at
the other end of the cable to determine optimum configuration. If one
device only supports HD, the other has to use it as well.

minseokoh@hanafos.com wrote:

I wanted to make sure if it can function as either a hub or switch and
if so, when it runs as a hub, the communciation mode must always be in
half-duplex, and when it runs as a switch, it must always be in
full-duplex.

While hubs are always half duplex, switches are generally, but not always
full duplex. Also, if you configure your NIC to HD, your connection to the
switch will be HD, though it shouldn't affect other ports.

While hubs are always half duplex, switches are generally, but not
always full duplex. Also, if you configure your NIC to HD, your
connection to the switch will be HD, though it shouldn't affect
other ports.

"Never" :) hardcode one side and not the other.

How Autoneg is supposed to work:

When both sides of the link are set to autoneg, they will "negotiate"
the duplex setting and select full duplex if both sides can do
full-duplex.

If one side is hardcoded and not using autoneg, the autoneg process
will "fail" and the side trying to autoneg is required by spec to use
half-duplex mode.

If one side is using half-duplex, and the other is using full-duplex,
sorrow and woe is the usual result.

So, the following table shows what will happen given various settings
on each side:

Auto Half Full

Auto Happiness Lucky Sorrow

Half Lucky Happiness Sorrow

Full Sorrow Sorrow Happiness

Happiness means that there is a good shot of everything going well.
Lucky means that things will likely go well, but not because you did
anything correctly :) Sorrow means that there _will_ be a duplex
mis-match.

When there is a duplex mismatch, on the side running half-duplex you
will see various errors and probably a number of late collisions. On
the side running full-duplex you will see things like FCS errors.
Note that those errors are not necessarily conclusive, they are simply
indicators.


--
The glass is neither half-empty nor half-full. The glass has a leak.
The real question is "Can it be patched?"
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to post, OR email to rick.jones2 in hp.com but NOT BOTH...

Rick Jones wrote:

"Never" :) hardcode one side and not the other.

How do you "hardcode" an ordinary consumer level switch?

Thank you all again for the valuable information.

Min

"James Knott" <james.knott@rogers.com> wrote in message
news:562dnUFAm4ZY3eTeRVn-rA@rogers.com...

Rick Jones wrote:

"Never" :) hardcode one side and not the other.


How do you "hardcode" an ordinary consumer level switch?

Most switches should at least allow this via a http interface or some gui.

Particular brand?

BernieM

bkbigpond wrote:

How do you "hardcode" an ordinary consumer level switch?


Most switches should at least allow this via a http interface or some gui.

Particular brand?

No, it's just a cheap made in China type. There was no mention of such a
thing in the docs for it.

BTW, please do not reply via e-mail, unless the message contains something
that should not be public.

"James Knott" <james.knott@rogers.com> wrote in message
news:uv2dnamEzKaoVuTeRVn-vQ@rogers.com...

bkbigpond wrote:

How do you "hardcode" an ordinary consumer level switch?


Most switches should at least allow this via a http interface or some
gui.

Particular brand?


No, it's just a cheap made in China type. There was no mention of such a
thing in the docs for it.

BTW, please do not reply via e-mail, unless the message contains something
that should not be public.

Sounds like it's 'auto' all the way. Sorry about replying via email ... it
was a mistake.

bernieM