Gigabit over bad wires?

A couple of years ago I ran Cat 5/E through my house, and now I've upgraded to a couple of gigabit switches (NetGear GS605) and some gigabit Ethernet cards (NetGear again) that claim that I am happily communicating at 1000 Mbps.

1) Does Gigabit Ethernet adjust its speed, based on the quality of the lines? So if I had put a sharp kink in the cabling somewhere, I might actually be running at only 416M or 732M or something?

2) Is there a free program somewhere that I can run on two of my PCs and verify the actual speed? Or is it just as easy (and accurate) to copy some big honking file and see how long it takes?

3) Am I correct in believing there is no way for my PC to communicate with the gigabit switches and ask them what they think about the line quality?

Thanks! Chris

Reply to
Chris Shearer Cooper
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No.

For house sized distances, your wire could be significantly worse than usual and still work fine. As you approach 100m (rare in most houses) the signal gets weaker and crosstalk relatively worse.

Kinks and untwisting at punchdown junctions are much more significant than at 100baseTX, but, unless you really over do it not likely to be a problem in a house.

You might try making a test cable of 10m or 20m, connecting it into one of your links, and then stomping on it, kinking it, tying knots in it, and see how much it takes before you notice problems. Then you will know how much beating it can take. That should be much cheaper than a cable tester.

-- glen

Reply to
glen herrmannsfeldt

Nope, it'll run at a gigabit with errors. [Unless you break something sufficient to make it fall back to 100BaseT, which AFAICT means removing a couple of pairs]

Look for ttcpw.exe for this. Big honking disk files will measure the speed of your slowest disk.

Managed switches will give you error counts, but low-end Gigabit SOHO switches won't tell you anything. You might be able to tell something from the error counters of your NICs in your terminal machines...

Reply to
William P.N. Smith

Yes. One would be netperf -

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binaries are probably "out there" somewhere, but generally folks build from source. There are no doubt other programs out there.

The copy a big honking file method is OK depending on how the big honking file is transferred. SMB may not cut it since it is request/response. FTP might. It also depends on how fast your discs happen to be and if they are on the same bus as the GbE NIC.

rick jones

Reply to
Rick Jones

Reply to
Chris Shearer Cooper

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Reply to
BernieM

"Chris Shearer Cooper" top-posted:

Google is your friend. First hit is a page with a pointer to:

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Reply to
William P.N. Smith

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