Maximum *Practical* Distance of CAT5e?
phillip...@gmail.com
help from this group before.
I need to connect two LANs about 500 feet apart with some flavor of
cable. A wireless bridge is not an option, unfortunatley. I've got a
couple of 100baseFX fiber switches, a big roll of fiber, and some SC
type terminators, but I'd really rather avoid using them since
a) the cable run is outdoors, I can't bury it ... damage is inevitable
b) terminating fiber isn't as trivial as crimping RJ45 plugs
I know that the official distance that CAT5e can run is 100 meters; to
read some web sites, you'd think that an attempt to go 101 meters would
be a catastrophic failure. Some imply that to violate the natural
order of things by running it further is to invite divine retribution.
But surely CAT5e can go more than 100 meters? Perhaps at reduced
speed? I don't need 100 mbps; 10 mbps would be fine as the bottleneck
is a shared 1 mbps internet connection. If ~150 meters is OK, but at
10 mbps, will my dumb 10/100 autosensing switches be smart enough to
fall back on the slower speed? Would I be better off using a new high
quality 10/100 switch that tries to make 100 mbps work, or an older 10
mbps only switch that forces the connection to the slower speed?
Just looking for some references or personal experiences on running
CAT5e further than it's supposed to go, because I don't want to mess
with fiber. Thanks.
John Navas
In <1131571941.6...@z14g2000cwz.googlegroups.com> on 9 Nov 2005
--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>
phillip...@gmail.com
> Why post this to alt.internet.wireless???
The answer is in the first line of my post:
> In <1131571941.6...@z14g2000cwz.googlegroups.com> on 9 Nov 2005
> 13:32:21 -0800, phillip...@gmail.com wrote:
>
> >This isn't a "wireless" question, but I've enjoyed the knowledgeable
> >help from this group before.
Google Groups didn't list an obvious better place to post it in the
alt.internet hierarchy, and as I said, friendly people have helped me
here before. I had hoped that someone would politely answer my
slightly off-topic question, rather than derail the thread into
something about Usenet etiquette.
Pierre
to 300 metres. CAT5 "may" work if you lock the speed down to 10mbs but will
definitely be very dodgy at 100mbs from my experience when pushing the
distance game.
Peter
<phillip...@gmail.com> wrote in message
news:1131571941.6...@z14g2000cwz.googlegroups.com...
Jenny Talyor
news:1131571941.6...@z14g2000cwz.googlegroups.com:
> This isn't a "wireless" question, but I've enjoyed the
> knowledgeable help from this group before.
>
> I need to connect two LANs about 500 feet apart with some flavor
> of cable. A wireless bridge is not an option, unfortunatley.
> I've got a couple of 100baseFX fiber switches, a big roll of
> fiber, and some SC type terminators, but I'd really rather avoid
> using them since a) the cable run is outdoors, I can't bury it
> ... damage is inevitable b) terminating fiber isn't as trivial
> as crimping RJ45 plugs
>
> I know that the official distance that CAT5e can run is 100
> meters; to read some web sites, you'd think that an attempt to
> go 101 meters would be a catastrophic failure. Some imply that
> to violate the natural order of things by running it further is
> to invite divine retribution.
Yes, I'm sure you can exceed the spec by a smidgeon or so, but you
are pushing the range by 75%.
> But surely CAT5e can go more than 100 meters? Perhaps at
> reduced speed?
Don't think so. The range limitation is related to signal delay
times and collision sensing, not the data rate.
> I don't need 100 mbps; 10 mbps would be fine as
> the bottleneck is a shared 1 mbps internet connection.
That's true today, but Broadband speeds are going up, soon ...
...allegedly :-)
> If ~150 meters is OK, but at 10 mbps, will my dumb 10/100
> autosensing switches be smart enough to fall back on the slower
> speed?
No, see earlier answer. Anyway, autosensing is about backward
compatibility, not range optimisation as in wireless LANs.
> Would I be better off using a new high quality 10/100 switch
> that tries to make 100 mbps work, or an older 10 mbps only
> switch that forces the connection to the slower speed?
Don't think it will work, see earlier.
> Just looking for some references or personal experiences on
> running CAT5e further than it's supposed to go, because I don't
> want to mess with fiber. Thanks.
>
I faced this problem with a customer who'd already laid the cable
through underground trunking, and then called me in when nothing
worked properly. The cable length was about 200m. Pings worked but
with a high drop-out rate, anything else was unusable because
connections kept dropping out.
Fortunately the cable was accessible in an intermediate building
about half-way. I cut the cable there, reterminated and fed each
half into ports of a 100Mbps switch, which cured the problem.
In your case, I suggest you plan to route the cable via a
waterproof enclosure about half-way along, into which you can
install a 100Mbps switch. You can power the switch from either end
using a compatible power-over-Ethernet (PoE) kit, e.g. D-Link DWL-
P100 or DWL-P200.
Jenny Talyor
news:dkttl3$gcv$1...@lust.ihug.co.nz:
> You may wish to run with coaxial cable (RG58) which is ok as
> 10-base for up to 300 metres. CAT5 "may" work if you lock the
> speed down to 10mbs but will definitely be very dodgy at 100mbs
> from my experience when pushing the distance game.
> Peter
Whilst technically this would work (at 10Mbps), the downside is that
it is based on technology that is already obsolete and, in my
experience, very flaky.
Jenny Talyor
@z14g2000cwz.googlegroups.com:
> A wireless bridge is not an option, unfortunatley.
Why is that?
John Navas
In <1131574150....@g14g2000cwa.googlegroups.com> on 9 Nov 2005
14:09:10 -0800, phillip...@gmail.com wrote:
>John Navas wrote:
>> Why post this to alt.internet.wireless???
>
>The answer is in the first line of my post:
Not a good answer.
>> In <1131571941.6...@z14g2000cwz.googlegroups.com> on 9 Nov 2005
>> 13:32:21 -0800, phillip...@gmail.com wrote:
>>
>> >This isn't a "wireless" question, but I've enjoyed the knowledgeable
>> >help from this group before.
>
>Google Groups didn't list an obvious better place to post it in the
>alt.internet hierarchy,
You must not have tried very hard.
<http://groups.google.com/groups?q=maximum-distance%20cat-5e>
First link is in newsgroup comp.dcom.cabling, and
several links of possible interest.
>and as I said, friendly people have helped me
>here before.
Not a good reason.
>I had hoped that someone would politely answer my
>slightly off-topic question, rather than derail the thread into
>something about Usenet etiquette.
More than slightly off-topic.
phillip...@gmail.com
> Not a good answer.
My apologies.
Jeff Liebermann
>I know that the official distance that CAT5e can run is 100 meters; to
>read some web sites, you'd think that an attempt to go 101 meters would
>be a catastrophic failure. Some imply that to violate the natural
>order of things by running it further is to invite divine retribution.
>
>But surely CAT5e can go more than 100 meters? Perhaps at reduced
>speed? I don't need 100 mbps; 10 mbps would be fine as the bottleneck
>is a shared 1 mbps internet connection. If ~150 meters is OK, but at
>10 mbps, will my dumb 10/100 autosensing switches be smart enough to
>fall back on the slower speed? Would I be better off using a new high
>quality 10/100 switch that tries to make 100 mbps work, or an older 10
>mbps only switch that forces the connection to the slower speed?
The correct newsgroup is comp.dcom.cabling. I posted articles there
on the topic before.
You're on the right track. One of my fun demonstrations is to put
connectors on both ends of a 1000ft roll of CAT5, plug it into my
office LAN switch and my laptop and surf merrily. No error shown on
the SNMP statistics in the switch. I also have several installations
using CAT5 at about 800ft which work just fine. I'm not sure exactly
what is the maximum, but my guess is about 1200ft.
As usual, there's a catch. You should use a switch or dedicated NIC
port on both ends. 10baseT-HDX (half-duplex) only. Don't bother
trying it with 100baseTX. It won't work. 10baseT-FDX (full duplex)
is problematic because of NEXT (near end crosstalk).
The orthodoxy in comp.dcom.cabling will claim that the rules are the
rules and that 100 meters was selected to insure that it will always
work under all circumstances. They are correct. I can create
situations where 10baseT-HDX will NOT work at much over 100 meters.
Examples on request. However, if you're careful, you shouldn't run
into any of these.
Your dumb and unspecified 10/100 NWAY switch will NOT guarantee
10baseT-HDX. It will start at the highest speed and stay there. To
force it down to 10baseTX, the easiest way is to insert a cheapo
10baseT hub (not switch) in the line. That will force both ends to
10baseT-HDX. (Hubs cannot do full duplex).
You might also consider using coax cable. I have one system with
about 1200 ft of RG-6/u coax, using 10base2 to 10baseT media
converters at each end. Works just fine. The 75 ohm to 50 ohm
mismatch is barely noticeable as the high cable loss eliminates any
reflections from being seen at the opposite end. Radio Shock sells a
Type F to BNC adapter which is all you need to make it work with
common CATV coax. Do NOT use RG-59/u. It's usually garbage or worse.
The following thread might be worth reading:
http://groups.google.com/group/alt.internet.wireless/browse_thread/thread/2a72743a913d8cb9
Incidentally, if you want to go miles over one twisted pair, it can be
done with SDSL. Some pairs of SDSL modems can talk to each other.
Flowpoint, Lucent DSL-HST, Elastic, PairGain, Xpeed, etc can work
without a DSLAM. 3com and Coppercom, cannot. 768-1500Kbits/sec
symmetrical maximum with the older equipment.
--
Jeff Liebermann je...@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
phillip...@gmail.com
Obstacles - wide and tall steel & concrete industrial buildings in
between the two areas in question. The more I look into this, the more
it appears I should just do it right and run fiber over a ~300 meter
more protected route rather than the hazard-filled 150 m direct route.
I appreciate your responses. Thanks.
TheDragon
"Pierre" <rain...@ihug.com.au> wrote in message
news:dkttl3$gcv$1...@lust.ihug.co.nz...
I have run 100 meg at 170m, was a tad intermittent. 150 was fine.
Stuart Robinson
For a link to fall within the definition of Cat5e that is indeed correct.
And is also the distance limit in the Ethernet spec for 100Mbs and 1Gb
Ethernet.
There is however no specific length limit for 10Mbs UTP Ethernet and in a
point to point link round trip delay times wont be an issue.
There is an attenuation and crosstalk test specified for 10Mbs Ethernet
and if your using Cat5 cable that equates to somewhere near 180M to 190M
of cable.
However as others have suggested you must force either end of the link to
10Mbs, the auto negotiation process is not a qualative check on the speed
capability of the cable.
Stuart.
stephen
news:memo.2005111...@srnet.compulink.co.uk...
> > I know that the official distance that CAT5e can run is 100 meters;
>
> For a link to fall within the definition of Cat5e that is indeed correct.
> And is also the distance limit in the Ethernet spec for 100Mbs and 1Gb
> Ethernet.
>
> There is however no specific length limit for 10Mbs UTP Ethernet and in a
> point to point link round trip delay times wont be an issue.
not true - the limit was 100m - but it says Cat3 or better.
in practice 10M will go a long way on good cable with good conditions - see
the separate post by Jeff Liebermann
>
> There is an attenuation and crosstalk test specified for 10Mbs Ethernet
> and if your using Cat5 cable that equates to somewhere near 180M to 190M
> of cable.
Agreed - but even that is conservative - i.e. it assumes cable that just
meets the Cat5 spec, and worst case combination of cabling practice, and
reciever sensitivity etc. The various versions of what is claimed to be "Cat
6" and "Cat 7" would give you more margin to play with.
there was a fair amount of slack built in to make everything reliable in the
real world - just think on how many patch leads get trodden on, how often
someone uses a different type of cable in a patch lead etc.
>
> However as others have suggested you must force either end of the link to
> 10Mbs, the auto negotiation process is not a qualative check on the speed
> capability of the cable.
Agreed. A relaible 2nd hand hub somewhere in the link may be an easy fix.
The old 3Com / Synoptics stuff seems to last forever....
if you must run a long way, then there are "long reach ethernet" products
designed to run up to 15 Mbps over several 100 m of poor quality cable
(phone wiring) - the cisco flavour is based on DSL type protocols. search
for LRE on their site if you want to go this way.
>
> Stuart.
--
Regards
stephe...@xyzworld.com - replace xyz with ntl
Stuart Robinson
Tis true, there was no specific length limit imposed in the standards for
10baseT, dont believe what you read in books written by so called experts.
The definitive reference document on Ethernet, the standard produced by
the IEEE says;
IEEE Std 802.3, 2000 Edition.
14.1.1.3 Twisted-pair media
The medium for 10BASE-T is twisted-pair wire. The performance
specifications of the simplex link segment are contained in 14.4. This
wiring normally consists of 0.4 mm to 0.6 mm diameter [26 AWG to 22 AWG]
unshielded wire in a multipair cable. The performance specifications are
generally met by 100 m of 0.5 mm telephone twisted pair. Longer lengths
are permitted providing the simplex link segment meets the requirements
of 14.4. A length of 100 m, the design objective, will be used when
referring to the length of a twistedpair
link segment.
Note the "Longer lengths are permitted" bit.
Stuart.
johnny
Another way to extend the range of ethernet is with LRE's. My employer is
using them with 4000 foot cat 3/5 ethernet runs.