Mailing List Archive: Network switch

Network switch - LED will not turn ON

Apr 26, 2021, 9:47 AM

Post #1 of 5 (371 views)

I have a computer that is about 70ft (about 21m) from the router I constantly get a very low speed over cat 5e (about 11Mbps).
Yesterday I've tried to connect that PC via Gigabit switch (Trendnet TEG-S80G) but when I disconnect the CAT5e cable from main router, the light on the switch did not light up at all.

I exchange the Trendnet switch with older one Belkin switch (that is closer to the router) and Belkin switch gave me green LED light without any problem in place that is 70ft away.
Plugging the Trendnet closer to the router worked as well.

So it seems to me Trendnet switches are limited how far it can be from the router.

Though, even with the Belkin switch having two green lights I'm still getting about 11Mbps transfer rate.

Re: Network switch - LED will not turn ON [ In reply to ]

matthewdconnell at gmail

Apr 26, 2021, 10:12 AM

Post #2 of 5 (371 views)

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On Mon, 2021-04-26 at 10:47 -0600, thelma@sys-concept.com wrote:
> 70ft (about 21m)

70 feet is nowhere near the limit for ethernet over CAT5e cable.
Combine the link behavior with poor performance and I suspect your
cable is just shoddy.

Re: Network switch - LED will not turn ON [ In reply to ]

thelma at sys-concept

Apr 26, 2021, 2:53 PM

Post #3 of 5 (371 views)

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On 4/26/21 11:12 AM, Matt Connell (Gmail) wrote:
> On Mon, 2021-04-26 at 10:47 -0600, thelma@sys-concept.com wrote:
>> 70ft (about 21m)
>
> 70 feet is nowhere near the limit for ethernet over CAT5e cable.
> Combine the link behavior with poor performance and I suspect your
> cable is just shoddy.

If they cable is the problem the LED port on the 70ft long cable on the switch would be orange "not green"; correct me anybody if I'm wrong.

I'll connect another box later on and try different cable, maybe cat 6

Re: Network switch - LED will not turn ON [ In reply to ]

antlists at youngman

Apr 27, 2021, 1:05 AM

Post #4 of 5 (371 views)

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On 26/04/21 22:53, thelma@sys-concept.com wrote:
> If they cable is the problem the LED port on the 70ft long cable on the switch would be orange "not green"; correct me anybody if I'm wrong.

I guess it depends what's wrong with the cable. And what the green light
is testing for.

There'#s a reason it's called "twisted pair" - that reduces interference
from all the wires stuffed close together. If it was badly connected
when it was made, or the cable's taken a hammering, or or or, you might
be getting a green light because the router says "the circuit is okay",
but poor data transmission because a bad quality cable is suffering from
excessive cross-talk.

Cheers,
Wol

Re: Network switch - LED will not turn ON [ In reply to ]

karl at aspodata

Apr 27, 2021, 2:03 AM

Post #5 of 5 (371 views)

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Wol:
> On 26/04/21 22:53, thelma@sys-concept.com wrote:
> > If they cable is the problem the LED port on the 70ft long cable
> > on the switch would be orange "not green"; correct me anybody if
> > I'm wrong.
>
> I guess it depends what's wrong with the cable. And what the green light
> is testing for.

As can be seen from

https://en.wikipedia.org/wiki/Autonegotiation#Electrical_signals

autonegotiation only runs at 10Base-T speeds. Its use is to make
sure that the endpoints are operating with the same parameters.

Note, it does not tests whether the cable and connector are suitable
for that negotiated link speed.

Also,

https://en.wikipedia.org/wiki/Gigabit_Ethernet#1000BASE-T

says that the tests are not done on all cable pairs, so even
if pair 1 and 2 are perfect, faulty pair 3 and 4 may make
communication fail.

///

So if the link led lights up, but the communication fails,
something between the mii's (the electronics, the chips)

https://en.wikipedia.org/wiki/Media-independent_interface

is faulty and it is with high probability that the cable is faulty.

Regards,
/Karl Hammar