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Date:      Fri, 15 May 1998 16:51:58 -0700 (PDT)
From:      "Jan B. Koum " <jkb@best.com>
To:        Evren Yurtesen <yurtesen@ispro.net.tr>
Cc:        freebsd-net@FreeBSD.ORG
Subject:   Re: your mail
Message-ID:  <Pine.BSF.3.96.980515163903.9926A-100000@shell6.ba.best.com>
In-Reply-To: <Pine.LNX.3.96.980513232648.22417D-100000@avrasya.ispro.net.tr>

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On Wed, 13 May 1998, Evren Yurtesen wrote:

>hello
>sorry maybe this is not a freebsd related problem but
>I do not know where else I can ask this question...
>
>at my office I want to expand my network with installing
>new hubs, how many hubs I can connect together? 
>
>like this 
>
>HUB------HUB------HUB-----...

	[I hope people on this list will correct me if I am wrong]

	This depends on a hub and media you use (fiber, 10Base, 100Base) 
In the old ethernet people follow the 5-4-3 rule: No more then five
segments interconnected with four hubs, and no more then three segments 
populated with hosts. Consider you have two computers A and B which each
connect to hub HA and HB like this:

A----HA === HB----B

	Then the total length between A and B should be no longer then 100
meters for 10BaseT (copper), 412 meters for 100BaseF (fiber media) and 205
meters for 100BaseT (copper).
	You should really look at the web site of your hub manufacturer to
get more info...

>
>and what can happen if I install too many hubs like this?

	They won't propagate the ethernet signal or will propagate it
poorly. Ever noticed why 10BaseT cables are not 500 meters long? *grin*

>
>would it cause collusion on my network? 
>(well another thing I should ask it, why does collusion 
>occurs on a network?)
>

	No, collisions are caused by for example two computer trying to
send a packet at the same time, or a hub trying to send a packet to a
computer and computer is trying to send a packet to a hub. Since a hub
can't send packets at the same time (think of it as electricity going
through the wire, that is all), it has a collision. See if you can find
out more on the web about CSMA/CD standard and look at Exponential Binary
Back-off principle.


>again I am so sorry that I ask a question not really related

	We are here to help... Most of the time. *grin*

-- Yan

>to FreeBSD (well my server uses FreeBSD eh...)
>
>+--------------------------------------------------------+
>| Name  : Evren Yurtesen - yurtesen@ispro.net.tr         |
>| S-mail: Mithatpasa Cad. No:1079/13 35290  Guzelyali    |
>| Home:+90-232-2857604 Work:+90-232-2463992 Izmir/TURKEY |
>+--------------------------------------------------------+
>
>
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