cable from building to unmanaged switch managed switch

[5nowman]

Hi,

 

Hope you are all well.

 

We have a network cable coming in from building A to building B.

In building B it connects to port one of an unmanaged negear 10/100 poe switch

 

We have a cisco 250x poe switch gigabit.

 

When I connect that cable to any port on the cisco switch no green lights come on yet they do on the netgear.

 

Regardless of what vlans are setup on the managed switch.. the green light should come on right to show data coming in?

 

Any ideas anyone? Please help as this does not make sense to me.

 

Many thanks and kind regards.

 

5nowman

[FN-GM]

What type of cable? Is it copper if fibre? If fibre what type of fibre?

 

If it’s copper could it be longer than 100M?

 

Any events in the Cisco switch that could be useful?

Edited August 17, 2023 by FN-GM

[5nowman]

What type of cable? Is it copper if fibre? If fibre what type of fibre?

 

If it’s copper could it be longer than 100M?

 

Any events in the Cisco switch that could be useful?

 

My apologies.. cable is copper. I will get cisco error tomorrow when I check again.

 

A computer connected to the new switch lit up ok.. it was just the cable that comes in from another building. Copper all the way in that building too.

 

Seems really odd. Thank you for replying!

[FN-GM]

How long are the switches? Does it need a crossover cable?

[Rob_D]

Just to check, you have checked to see if there's a connection? (not sure about cisco, but our HP/Aruba switch lighting can be set to just show POE)

If you've got a cable tester, it might be worth checking the cable run, could be just the transmit or receive cable pair has been damaged.

[Davit2005]

Plug a laptop into the copper coming from the other building see if you get a light, then plug the laptop into the Cisco switch and see if you get a light if both show link lights on the laptop check if you need a crossover. Some switches have auto crossover and some don't as @FN-GM mentions.

[steveg]

Is the port on the cisco switch set to auto sensing? Might have been manually set to gig at some point.

[3s-gtech]

Can you test with a decent switch (100/1000) instead of the Netgear? I wonder if it’s struggling to negotiate with it. Could be cable damage/termination but my first test would be switch.

[5nowman]

The cable from the building to the netgear. I put a crossover at the end of the cable and plugged it into the cisco

No light

 

Plugged cable into cisco direct... no event log eg port connected.

 

Why is there no light on the cisco but there is on the netgear.

[3s-gtech]

My Ciscos will not talk to stuff below 100mb. I saw similar problems when I upgraded our setup. You may also have spanning tree disabling the port (I have to disable it on any port that has a switch downstream).

[5nowman]

I traced it back.

 

The cable connects to a gigabit managed switch.

 

When plugged into the new switch no green light.

 

Unmanaged 10/100 switch and you get the green light.. no need for a cross over no uplink port on the switch.

 

 

My Ciscos will not talk to stuff below 100mb. I saw similar problems when I upgraded our setup. You may also have spanning tree disabling the port (I have to disable it on any port that has a switch downstream).

[FN-GM]

Why is there no light on the cisco but there is on the netgear.

 

The quickest way to determine this is by looking at the logs in your managed Cisco switch.

[5nowman]

Cisco switch never showed any port up port down or anything.

 

I figured out the problem!

 

Pin 5 seems to have broken along the way. The netgear switch still sees this.. cisco ones says "get lost" and doesn't even show a green light which is odd..

 

Anyone seen this before?

 

 

 

The quickest way to determine this is by looking at the logs in your managed Cisco switch.

[3s-gtech]

Yes. Moving from Cisco to Aruba, I had to have several outlying rooms re-cabled as some ports no longer worked. When tested, they had cable faults. They worked in the old Cisco and previous HP switches!

[steveg]

Cisco switch never showed any port up port down or anything.

 

I figured out the problem!

 

Pin 5 seems to have broken along the way. The netgear switch still sees this.. cisco ones says "get lost" and doesn't even show a green light which is odd..

 

Anyone seen this before?

 

It sort of makes sense - 100 meg only uses pins 1,2,3 and 6. Gigabit uses all 8. I'd have thought connecting a 100 meg switch would force the faster one down to 100 and it would work, but evidently not.

[Davit2005]

Maybe it of worked if you'd forced the ports to 10/100 both ends (apologies if you tried this already). Green and orange pairs normally enough for 10/100 even some extenders I've used in the past have only used 2 pairs and that is how those cable economizers normally work Edited August 24, 2023 by Davit2005