Full Duplex Hub?

2001-03-02 Thread Patrick McAllister

I know this isn't a Cisco question per se, and I apologize in advance.=20

Is there such a thing as a full duplex 100BaseTx hub or repeater? I =
thought all hubs/repeaters had to run in half duplex.

Here's the scenario, of sorts. I have a Cogent 1200 100Base TX Class I =
Repeater. I hook two PC's up to them and start transferring files. =
Everything works swimmingly. I look at the config after I'm done and =
both NIC's in the PC's are set to full duplex. There is (of course) no =
setting on the Cogent, and there is (of course) a collision light, but =
it never flashed during the transfer. I know I'm not the sharpest knife =
in the drawer, I accept that. But have I been laboring under a =
misconception all this time?=20



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Re: Full Duplex Hub?

2001-03-02 Thread Mark Holloway

Well, a full duplex hub is typically called a switch.  Just because the NICs
are at 100 Full doesn't mean anything.  Many times devices can be set for
auto negotiate and not configure properly.  You can force a setting on a NIC
and even if it wrong, it will still work, but there may be errors and
retransmissions will occur.  If you only have two devices in this hub and
they are only talking to each other, there may not be any collisions.

Regards,
Mark

""Patrick McAllister"" <[EMAIL PROTECTED]> wrote in message
007201c0a383$7e2ff7d0$6401a8c0@cartman">news:007201c0a383$7e2ff7d0$6401a8c0@cartman...
> I know this isn't a Cisco question per se, and I apologize in advance.=20
>
> Is there such a thing as a full duplex 100BaseTx hub or repeater? I =
> thought all hubs/repeaters had to run in half duplex.
>
> Here's the scenario, of sorts. I have a Cogent 1200 100Base TX Class I =
> Repeater. I hook two PC's up to them and start transferring files. =
> Everything works swimmingly. I look at the config after I'm done and =
> both NIC's in the PC's are set to full duplex. There is (of course) no =
> setting on the Cogent, and there is (of course) a collision light, but =
> it never flashed during the transfer. I know I'm not the sharpest knife =
> in the drawer, I accept that. But have I been laboring under a =
> misconception all this time?=20
>
>
>
> _
> FAQ, list archives, and subscription info:
http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
>


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Re: Full Duplex Hub?

2001-03-03 Thread Patrick McAllister

To all who responded, thank you.=20

Mark - that's one (of my no doubt many) points of confusion. I know a =
switch breaks up collision domains and a hub is shared media, therefore =
one collision domain. I also know that the NIC set to 100 means nothing =
as far as half or full duplex goes, as you can run 100 in either. I've =
searched around - trying Cogent's site though I think they are out of =
business - even reading and rereading Charles Spurgeon's Ethernet - The =
Definitive Guide. Yeah, I know, there's reading and there's the real =
world, I just wanted to check if my logic was correct. No where do I see =
anything about 100 Full Duplex hubs. Switches, sure, that's their reason =
for living for the most part. I have found some writings on the web =
saying that with certain "proprietary" (read - not based on the Ethernet =
Standard) hubs will run at 100 Full Duplex. What I haven't found is WHY =
or HOW they can do this.=20

Gene - yes that makes sense, but how do the NIC's decide to run half =
duplex if I've forced them to full? (I avoid auto-negotiate like the =
plague)?=20

David - Exactly my understanding. Collision detection is turned off at =
full duplex, so how in the hell is this thing working? I suspect the =
answer lies in the hardware specs (clever, aren't I?) but since I can't =
find them I'm bumbling around blindly.

Anyway, thanks for all the responses, it helps to no I wasn't entirely =
crazy...regarding this at least.

Thanks again
Patrick


"Mark Holloway" <[EMAIL PROTECTED]> wrote in message =
97poso$m4e$[EMAIL PROTECTED]">news:97poso$m4e$[EMAIL PROTECTED]...
> Well, a full duplex hub is typically called a switch.  Just because =
the NICs
> are at 100 Full doesn't mean anything.  Many times devices can be set =
for
> auto negotiate and not configure properly.  You can force a setting on =
a NIC
> and even if it wrong, it will still work, but there may be errors and
> retransmissions will occur.  If you only have two devices in this hub =
and
> they are only talking to each other, there may not be any collisions.
>=20
> Regards,
> Mark
>=20
> ""Patrick McAllister"" <[EMAIL PROTECTED]> wrote in message
> 007201c0a383$7e2ff7d0$6401a8c0@cartman">news:007201c0a383$7e2ff7d0$6401a8c0@cartman...
> > I know this isn't a Cisco question per se, and I apologize in =
advance.=3D20
> >
> > Is there such a thing as a full duplex 100BaseTx hub or repeater? I =
=3D
> > thought all hubs/repeaters had to run in half duplex.
> >
> > Here's the scenario, of sorts. I have a Cogent 1200 100Base TX Class =
I =3D
> > Repeater. I hook two PC's up to them and start transferring files. =
=3D
> > Everything works swimmingly. I look at the config after I'm done and =
=3D
> > both NIC's in the PC's are set to full duplex. There is (of course) =
no =3D
> > setting on the Cogent, and there is (of course) a collision light, =
but =3D
> > it never flashed during the transfer. I know I'm not the sharpest =
knife =3D
> > in the drawer, I accept that. But have I been laboring under a =3D
> > misconception all this time?=3D20
> >
> >
> >
> > _
> > FAQ, list archives, and subscription info:
> http://www.groupstudy.com/list/cisco.html
> > Report misconduct and Nondisclosure violations to =
[EMAIL PROTECTED]
> >
>=20
>=20
> _
> FAQ, list archives, and subscription info: =
http://www.groupstudy.com/list/cisco.html
> Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]

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