Mailinglist Archive: opensuse (908 mails)

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Re: [opensuse] On redundant technology and the context for its use
On 06/05/2016 10:52 AM, Carlos E. R. wrote:
On 2016-06-05 16:33, James Knott wrote:

I'd like to hear it. The only thing a hub can do that an unmanaged
switch can't do is monitor traffic. But sticking a 10 Mb half duplex
device into a modern network is going to kill performance. On the other
hand, a managed switch, with port mirroring, is capable of monitoring at
full wire speed.
Except that simultaneous speed or however is called, gets killed.
Everything on all ports have to be copied onto a single port, so max
total speed is that of that single port.

Similar to having a gigabit hub.

It's unlikely you'd set it up to monitor all ports. You'd be much more
likely to monitor just one port, such as to a single computer, or
perhaps the Internet connection. Even if you did try to monitor all
ports it simply means you'd be overflowing the mirror port, not
interfering with the traffic passing through the switch

Are you aware of any company that still makes Ethernet hubs? I haven't
seen a new one in many years. On the other hand, I recall one project I
was working on, when someone was trying to find out why the network was
so slow. It turned out someone had used a hub, instead of a switch. In
this applications, a lot of computers were being reimaged via the
network and the 10 Mb hub really killed performance.
If the internet connection is a 1 MB ADSL (what I had not long ago), a
10 MB hub is fine as long as you only connect to internet, not between
the computers in the house. Internet is slow, after all (in that house).

This wasn't even involving the Internet. It was bringing disk images
from a server to the computers being reimaged.
However, as soon as you try to transfer a file between two computers,
performance is terrible. Even a usb flash stick writes faster.

I think that is what I had till recently, a 100Mb hub. Wish I could confirm.

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