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Overcoming collision domain limits
klenze Apr-11-02 05:55 PM
or overcoming the inherent distance limits between a switch and a pc on a 100mbps segment.

I've been looking for repeaters, but most of them are actually Media Converters or Transceivers. These converters allow you to go from TX to FX etc. I simply need a repeater that regenerates data signal to make up for attentuation (data loss) at a distance up to 700 ft. The repeater needs In and out of female end of RJ-45.

So now I'm thinking of using a switch to regenerate signal (a switch is actually a hub with a repeater)

Anyone knows the total # of switches that can be uplinked and the limitations on distance in between and alltogether? Isn't the maximum collision diameter 205m?

So from what I understand, all segments combined can't exceed 205m.

Yet another option is to create a separate collision domain using a Canary Lan Extender.

Any ideas?

1. RE: Overcoming collision domain limits
DJ Net2Infinity Apr-11-02 06:03 PM
In response to message 0
If it were me I would run Fiber

2. RE: Overcoming collision domain limits
trumpetr Apr-12-02 06:57 AM
In response to message 0
Look down a few posts in this forum for "Network Segment lengths" it has some good info in it. Also, FWIW here is a quote from a Net+ newsgroup that is having the same discussion

<begin quote from alt.certification,network-plus>

Ok. imagine five 100-meter lengths of cat5 ethernet cable, with RJ45
jacks on each end. You have an office buidling 500 meters across and
have three computers you'd like to put on a single network. One
computer is on each end of the building, with the third computer smack
in the middle. The 5 ethernet cables represent the "5" in the
5-4-3...segments on the network.

You hook up one end of cable to a computer on one end of the building,
but of course it won't reach either computer...it's 400 and 150 meters
too short, respectively. So you add a repeater, which boosts the
signal. This almost reaches the middle computer, but short by 50
meters. You add a SECOND repeater, and you reach the computer in the
middle. You add 2 more repeaters and then you can reach the other
end. The repeaters represent the "4" in the 5-4-3...maximum number of
repeaters. An active hub (meaning it has a power plug) is considered
a "multi-port repeater".


So all three computers are hooked up. Now Joe Smith in accounting
gets an idea. He adds his computer between the 1st and 2nd repeaters
and never tells the network administrator. This is not allowed and
will cause problems on the network because of the "3"...a maximum of 3
segments with computers on the network (his computer would populate
*4* segments, since its between repeaters 1 and 2...placing a computer
between repeaters 3 and 4 would do the same thing)

So theres the 5-4-3 rule. Max 5 segments, 4 repeaters, 3 segments

4. RE: Overcoming collision domain limits
lbyard Apr-12-02 11:13 AM
In response to message 2
That might be OK if a 10 Mhz network meets requirements. The 5-4-3 rule applies to 10BASE-T, not 100BASE-TX. 205 Meters is correct for 100BASE-TX copper. I agree with DJ Net2Infinity’s post and would use fibre for a 700 foot run. Larry

5. RE: Overcoming collision domain limits
dbradsher1 Apr-13-02 10:26 PM
In response to message 4
Not only will using fiber make it easier and faster but it will also give you more bandwidth possibilities and no need to upgrade to a faster backbone for years to come provided you would like to add more pc's,printers,servers etc. in the future.

6. RE: Overcoming collision domain limits
Mosquito57 Jun-22-02 05:00 PM
In response to message 5
I hope this answer don't come too late, but I just registered today.

After reading this thread, I've search the net for domain collisions, and found a very helpfull and well documented web site : www.ethermanage.com/ethernet

You'll find there answers on ethernet history, hubs (cat I & II), switches, distance limitations (and the reason why), cabling rules and so on. Some pages concerning 10BaseT are not referenced in the main pages, but nevertheless can be accessed (for example
www.ethermanage.com/ethernet/10quickref/ch7qr_4.html witch talks about domain collisions in a 10BaseT multisegment network)

I think it's possible to solve your connection problem using two 100BaseTx switches, or a switch and a hub.

A switch is NOT actually a hub with a repeater. A switch splits the whole network in as many collisions domains as used network ports.

Hope this helps.
(And hope my froggy english is good enough )


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