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Need Ethernet Hub - NOT Switch

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Anonymous
March 15, 2005 10:15:52 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

I'm looking for a simple unmanaged 16 port rack mountable 100mbit
ethernet hub, which is NOT a switch.

We bought a Linksys EF2H16 because it was advertised as a hub, but after
monitoring it found it acting as a switch. Linksys tech support after
lots of probing told me that the older versions were in fact just hubs
but they had silently substituted newer silicon that acted as a switch
in the current version.

Can anyone suggest a product that will do what I want?


--
Ken Mandelberg | km@mathcs.emory.edu
Emory University |
Dept of Math and CS | Phone: Voice (404) 727-7963
Atlanta, GA 30322 | FAX (404) 727-5611

More about : ethernet hub switch

Anonymous
March 15, 2005 10:15:53 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

can you go in and set the cache so small it will always overflow?
According to another thread here, most switches become hubs when the
cache fills up....
Anonymous
March 16, 2005 2:43:02 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

"Ken Mandelberg" <km@mathcs.emory.edu> kirjoitti viestissä
news:D 17tro$s20@mathsunf.mathcs.emory.edu...

> I'm looking for a simple unmanaged 16 port rack mountable 100mbit
> ethernet hub, which is NOT a switch.

WHY would you want to use a hub, not a switch?

I can imagine you could use a small hub to monitor traffic, maybe in some
lab or test environment, but why 16 ports and a fixed installation?


--
Petri Krohn
Helsinki Neighborhood Networking Association
HelsinkiOpen -- http://www.helsinkiopen.net
Related resources
Anonymous
March 16, 2005 2:43:03 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d18v25$17qm$1@news.bbnetworks.net>,
Petri Krohn <petri.krohn@iki.fi-n-l-a-n-d.invalid> wrote:
:"Ken Mandelberg" <km@mathcs.emory.edu> kirjoitti viestissä
:news:D 17tro$s20@mathsunf.mathcs.emory.edu...

:> I'm looking for a simple unmanaged 16 port rack mountable 100mbit
:> ethernet hub, which is NOT a switch.

:WHY would you want to use a hub, not a switch?

:I can imagine you could use a small hub to monitor traffic, maybe in some
:lab or test environment, but why 16 ports and a fixed installation?

Perhaps he needs to monitor a number of devices.

Perhaps (considering his university email address) he needs it for
teaching purposes, so a number of students can all get copies of the
packets.

Perhaps he needs to connect devices that have difficulty with
autonegotiation .

Perhaps he needs to connect a number of devices that need layer 2
frames that are not passed through switches, such as CDP (Cisco
Discovery Protocol) or Cisco PIX LAN failover keep-alives.
--
History is a pile of debris -- Laurie Anderson
Anonymous
March 16, 2005 6:02:37 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

On Wed, 16 Mar 2005, J. Clarke wrote:

> 100TX only though, not dual-speed, if that's a problem.

No offence meant, but surely there can be no such thing, literally, as
a "dual-speed hub"? There are/were some boxes which contain, in
effect, a 10M hub and a 100M hub, interconnected by a switch. They
used to be marketed as "dual speed hubs", but technically we knew what
that really meant.
Anonymous
March 16, 2005 6:02:38 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <Pine.LNX.4.61.0503161457220.20522@ppepc56.ph.gla.ac.uk>,
Alan J. Flavell <flavell@ph.gla.ac.uk> wrote:
>On Wed, 16 Mar 2005, J. Clarke wrote:
>
>> 100TX only though, not dual-speed, if that's a problem.
>
>No offence meant, but surely there can be no such thing, literally, as
>a "dual-speed hub"? There are/were some boxes which contain, in
>effect, a 10M hub and a 100M hub, interconnected by a switch. They
>used to be marketed as "dual speed hubs", but technically we knew what
>that really meant.


Right idea, but I beleive that it's a bridge that connects the two
sides and I expect that the chip used is much faster than the 10Mb
side can either source or sink bits and so it's effectivly invisible.
A basic bridge passes all traffic.

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 16, 2005 6:02:38 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Alan J. Flavell wrote:

> On Wed, 16 Mar 2005, J. Clarke wrote:
>
>> 100TX only though, not dual-speed, if that's a problem.
>
> No offence meant, but surely there can be no such thing, literally, as
> a "dual-speed hub"? There are/were some boxes which contain, in
> effect, a 10M hub and a 100M hub, interconnected by a switch. They
> used to be marketed as "dual speed hubs", but technically we knew what
> that really meant.

A dual speed hub used to be two repeaters linked by a single bridge.

I mentioned that mainly to save clicking the link if he needs 10baseT.

--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
Anonymous
March 16, 2005 6:41:45 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Thanks for all the responses.

As to why we don't want a switch:

We already have a large rack mounted mesh of switches. The hub was to
consoldiate a collection of wireless access points onto one of the
switch ports. Because of mobility issues we didn't want to deal with
any issue of the switch having to relearn port association when a
wireless session flipped between access points. It would also be a plus
to be able to monitor from any of the hub ports.

We used the Linksys EF2H16 "hub" for a while thinking it was as advertised
not a switch. Mostly it worked fine, even when laptops moved between access
points. However, sometimes it didn't. In some cases we saw a laptop able
to broadcast its dhcp request all the way through to the dhcp server, but
unable to get its unicast reply. The "hub" was confused about what port to
send the reply to, and this persisted for hours.

That example might just indicate a poor Linksys implementation, or even a
defective piece of hardware. I was really only expecting a few second of
trouble on port switching. Still it seems to me a real hub is what we want.
If we wanted a switch we could connect directly to ports on our managed
switches and not need a hub at all.

Ebay references:

Thanks also for the ebay pointers on older hubs. I might go this way, though
my preference would be to get a new/warranteed piece of hardware if such a
thing exists.

--
Ken Mandelberg | km@mathcs.emory.edu
Emory University |
Dept of Math and CS | Phone: Voice (404) 727-7963
Atlanta, GA 30322 | FAX 727-5611
Anonymous
March 16, 2005 6:41:46 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

In article <d19k3p$qje$1@finch.mathcs.emory.edu>,
Ken Mandelberg <km@mathcs.emory.edu> wrote:
>Thanks for all the responses.
>
>As to why we don't want a switch:
>
>We already have a large rack mounted mesh of switches. The hub was to
>consoldiate a collection of wireless access points onto one of the
>switch ports. Because of mobility issues we didn't want to deal with
>any issue of the switch having to relearn port association when a
>wireless session flipped between access points. It would also be a plus
>to be able to monitor from any of the hub ports.
>
>We used the Linksys EF2H16 "hub" for a while thinking it was as advertised
>not a switch. Mostly it worked fine, even when laptops moved between access
>points. However, sometimes it didn't. In some cases we saw a laptop able
>to broadcast its dhcp request all the way through to the dhcp server, but
>unable to get its unicast reply. The "hub" was confused about what port to
>send the reply to, and this persisted for hours.
>
>That example might just indicate a poor Linksys implementation, or even a
>defective piece of hardware. I was really only expecting a few second of
>trouble on port switching. Still it seems to me a real hub is what we want.
>If we wanted a switch we could connect directly to ports on our managed
>switches and not need a hub at all.
>
>Ebay references:
>
>Thanks also for the ebay pointers on older hubs. I might go this way, though
>my preference would be to get a new/warranteed piece of hardware if such a
>thing exists.
>

I believe the HP Procurve line has a lifetime warranty. If you're
worring about warranty coverage buy two or three on ebay and keep them
for spares. I see Cisco 24 port 10/100 hubs are going for as little
as $40 on ebay.

--

a d y k e s @ p a n i x . c o m

Don't blame me. I voted for Gore.
Anonymous
March 16, 2005 9:16:10 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Ken, at the risk of stating the obvious, you're at a University, can
you not just email your networking colleagues explaining your problem
and asking if anybody can swap a hub for a switch? I have two 16 port
hubs sitting in a cupboard, surely there must be loads in Emory.

And if you can't get a 16-port hub you should be able to daisy-chain
two 8-porters together.

John
Anonymous
March 16, 2005 10:51:44 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

"Ken Mandelberg" <km@mathcs.emory.edu> kirjoitti viestissä
news:D 17tro$s20@mathsunf.mathcs.emory.edu...


>I'm looking for a simple unmanaged 16 port rack mountable 100mbit
>ethernet hub, which is NOT a switch.

There is right now on eBay two 3C250's for $19.95 (for both),
plus $39.95 shipping. The shipping is a little high, but they
are a little heavy. Those are real 100baseTX 24 port
rack-mountrepeaters, maybe even class I.

-- glen
Anonymous
March 16, 2005 11:22:39 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Al Dykes wrote:

>(snip)

> If you buy a used box made by Cisco/3Com/HP you can trust that if it
> says it's a hub, it's a hub.

> before buying you should get the model # and grap the manual from the
> manufacturer's web site and read up to make sure you know what youi
> are buying. I wouldn't trust a seller to describe the item correctly.

> HP has a lifetime warranty on some of it's gear. Hard to go wrong.

As far as I know, they are all hubs, some repeaters and some
bridge/switch (two different words for the same thing).

Since the original hubs were repeaters, they got associated with the
word hub, but hub is supposed to describe the wiring topology, not the
electrical characteristics of the box. (There are also coaxial
repeaters and AUI repeaters, neither of which are usually called hubs.)

-- glen
Anonymous
March 17, 2005 7:01:09 PM

Archived from groups: comp.dcom.lans.ethernet (More info?)

Your switch is configurable? Can't you configure all ports into
promiscuous mode?
August 7, 2012 4:06:18 PM

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