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TOPIC: Patch Panel / NIC combo not working

Patch Panel / NIC combo not working 14 years 3 months ago #7139

Many THANKS in advance,

1. Working setup:
DLINK 713P router --> 1 ft crossover cable --> CISCO Catalyst 2924 --> 3 ft st. cable --> Patch Panel (non powered) --> ~30ft st. cable in wall --> wall outlet --> 3 ft st. cable --> laptop w/gigabit NIC card.

All cables/ports are CAT 5E.

2. Breaks if:
If you swap out the laptop for a recent model desktop ("slower NIC") or any other system without the gigabit NIC, no link appears on switch and packets are dropped.

3. Also, if you plug the DLINK router into the wall outlet --> patch panel --> switch, this also fails. Older model DLink with, i'm sure, slower ports.

numerous outlets combinations on wall outlets/patch panel have been tested where 1. works but 2&3 fail. My problem appears to be the lack of "power" in the NIC cards. Is there anyway around this, with a setting change? The total cable length is way under 60ft (although in 3 segments, system to wall, wall to patch panel, panel to switch) Or is there another solution not involving additional hardware?

Re: Patch Panel / NIC combo not working 13 years 9 months ago #9515

  • jwj
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The length of your cable is definitely not the problem since Category 5 is capable of a total length of approximately 100 meters. What this sounds like to me is a problem with auto-negotiation of the speed/duplex. Try to set up the old NIC or whatever you are plugging into the wall jack to the highest speed it is capable of, and at full duplex, e.g. 100 Mbps, full duplex. Then, on the 2924, I would configure the port exactly the same as the NIC, e.g. 100 Mbps, full duplex.

Re: Patch Panel / NIC combo not working 13 years 9 months ago #9536

Somebody correct me if I am wrong, but some switch's are able to detect what device is connected on the other side of the cable, whether it is crossed or straight and set up the proper pinout internally.

I wouldn't be surprised if some NIC's could do the same. Say for instance that you wanted to set up two machines ad-hoc and only had a straight-through cable. The NIC could detect this and switch the Tx/Rx and make it work.

If your gigabit NIC works in this manner and your 100Mbit NIC's don't, then maybe somewhere along the way you used 568a when you should have used 568b (or vice versa) and crossed the connection; Perhaps your patch panel.

I am interested to know from the experts if this is a possibility or if I am way out in left field.


Cross-over 13 years 9 months ago #9544

I've certainly experienced switches and routers that can do auto-crossover on their ports so I don't see why NICs couldn't do it too. That would be one possible explanation for what you're seeing. Another could be speed/duplex mismatches as jwj suggests - try setting everything to 'auto' or fixing everything at say 100 half. Another possibility might be a problem with your wall cabling. To eliminate this, try tour PC and laptop test with a long patch lead directly into the switch rather than through the wall cable and patch panel. If both work then the wall cabling must be causing the problem somehow, but if the problem remains it must be something else. Think how you can break the problem down into chunks and use that approach to isolate the chunk causing the failure
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