Wireless Networking Ethernet linked access point appears sensitive to cable length well below specified limits.

Ethernet linked access point appears sensitive to cable length well
below specified limits.

I�m seeking to locate a wireless access point remote from my main
router, a D-Link DI-524 whose wireless function has been turned off. The
wireless access point is being implemented with a nearly identical
D-Link DI-524 wireless router whose DHCP function has been turned off.
The IP address of the second D-Link DI-524 wireless router has been
altered so as not to conflict with the IP address of the first router.
One of the LAN outputs of the first router is connected to one of the
LAN outputs of the second router so that it acts like a switch.

I have tested the above configuration at three locations linked by three
different CAT5 cables.

Location #1 � WORKS fine when linked by commercially constructed 10�
long CAT5 cable.

Location #2 � WORKS fine when linked by home built 40� long CAT5 cable.

Location #3 � DOES NOT WORK when linked by home built 100� long CAT5
cable. � Not only is there no communication over the link, but the
lights on both routers do not even indicate a connection. YET, if at
this same location #3, the 100� long cable is plugged into any one of
several computers, the connection indicator lights come on immediately,
and full normal network access is quickly obtained.

As the cable length is well under the 100 meter (300 feet) maximum
length for Ethernet, at first I thought that maybe the third cable is
somehow wired differently, perhaps as a �Cross over cable� rather than
as a �straight through� cable.  I understand that some interfaces can
cross and un-cross a cable automatically as needed.  I am uncertain
whether or not the LAN ports of the DI-524 have that feature, but an
examination of all of my cables, both home made and commercially
assembled, and all appear to be wired �straight through.�

I�ve also sought to confirm that the problem is not associated with the
RJ45 connector at the end of the cable. The symptoms are unchanged when
a short (10 foot long) Ethernet extender (female to male) cable is used,
so the connector at the end of the 100� cable is not disturbed as I
switch between the D-Link DI-524 and my lap-top computer..

Any Suggestions?

I nominate this post as best of the month for well formed question,
good initial troubleshooting, and supplied information.

Let me have coffee, feed the dogs, moves the cows to another pasture,
then I'll look it over.

added cabling & ethernet newsgroups -
Wonder if a small ethernet cable tester has been used to verify proper pairs
?
--

windsurferLA wrote:

These homebuilt cables, which wiring pattern did you use?
T-568A or -B ?  If you don't know what I'm talking about,
it is highly likely you split a pair.

Please do not complain "but the other comp works".
Difference NICs and drivers are more error-tolerant
and have more robust fall-backs.

Electrons may be color blind, but they _do_ know
who their dance [twist] partners are.

-- Robert

On Sat, 03 May 2008 20:22:07 GMT, Robert Redelmeier


Huh?  Unless he did something really disgusting, like EIA-568A on one
end and EIA-568B on the other, either wiring standard will work.  The
color codes are different, but the pairing is identical.

Drivel:  I once had some hired help in wiring a medical office.  I did
568B while my hired help did 568A wiring.  Nothing worked when we were
done.  Never ignore the obvious.


True.  I recently demonstrated that I can run 10baseT-HDX (half
duplex) through 2,000 ft of CAT5e (two rolls in series), without any
data degradation.  If I had a 3rd roll, I would have added it.  The
catch is that it would only work between my Cisco 1900 ethernet
switch, and a desktop with an Intel Pro100 card.  It would function to
other devices (several laptops, assorted junk around the office), but
these showed various errors in the switch SNMP logs.


Perhaps a matchmaker would be appropriate?


See item #6:
<http://www.LearnByDestroying.com/nooze/support.txt>

--
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558