[Klug-general] network lags - electrical interference?

[Michael E. Rentell]

Twisted pair - 19th century technology. Remarkably simple and useful :-)
MikeR
PS: I like steam trains too.

On 26/01/10 22:01, Kevin Groves wrote:
> Yes that's the point of twisted pair. Coax has two parallel conductors
> and any simliar parallel conductors with flowing AC current can induce
> current in the other (as Julia says - transformers and yes, regs say
> separation of Band I and Band II class of cables due to induction during
> fault events - a few hunderd Amp no mater how short a time being induced
> into UTP could be quite interesting). Twisted pair appempts to stop this
> parrallel run and generally does it. Don't often have a problem with it.
>
> Regarding the problem I would agree and say hub/switch possible. As
> you've gone Gigabit watch quality of cable and length and any possible
> crap cables. If found you can generally abuse cable length of quality
> quite a bit but one bit of gear that can't cope and there is little you
> can do.
>
> It might be worth checking cable termination as I've found some CAT5
> plugs to look fine but sometimes just won't work in certain sockets.
> Also if it's regular times then sling Wireshark on and see if it's a
> broadcast or repeated retry of packet send/ack.
>
> If you can get hold of one check the cables out with a decent tester
> (not those crappy £10 boxes), I can certainlly recomend the Fluke range
> as I've just recently bought one and it's already earnt it's way. :-)
>
> Kev,
>
>
> |
>
>
> On 25/01/10 14:42, Mike Evans wrote:
>>
>> On 25/01/10 13:50, Alan @ COMM-TECH wrote:
>>
>>
>>> I think therefore that the issue is down to some sort of magnetic or
>>> electrical interference, like a faulty lighting circuit or some leery
>>> telephone cable crossing
>>>
>> Twisted pair is remarkably immune to interference.  Back in the early
>> days of local area networking for PCs when I worked for Novell we were
>> developing some network cards and comparing performance over ethernet
>> cable (which used to be coax) and twisted pair.  The coax would quite
>> often loose packets when the soldering iron was placed close to the reel
>> of cable we were using as our test.  (Those soldering irons that have a
>> thermal cut-out built in.) Twisted pair took all manner of abuse - we
>> could even run an electric drill with worn brushes next to it.
>>
>> The fact that your drop-out runs for variable lengths of time does
>> indicate that there is probably a co-incidence with some sort of human
>> activity if only you can work out what it is.
>>
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>
>
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