Network speed?

Questions about cabled networking
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Stretch
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Network speed?

Post by Stretch » Thu Sep 27, 2007 9:00 pm

What sort of speed should I be getting when moving a large file (600MB) via eth0 from PC 1 to PC 2 via an adsl router/modem?

I seem to getting round 2.5 - 2.8 MB/s which I think is slow for a 100Mbs / 1 Gbs LAN.

Husse
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Post by Husse » Fri Sep 28, 2007 7:49 am

It depends on the nics in the computers, the cables and the router and the quality may vary considerably
This is a speed of around 20 Mbps so it is a bit low
Can you get the speed for small files - some equipment does not like large files
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scorp123
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Re: Network speed?

Post by scorp123 » Fri Sep 28, 2007 11:36 am

Stretch wrote: I seem to getting round 2.5 - 2.8 MB/s which I think is slow for a 100Mbs / 1 Gbs LAN.
Were you transferring via WiFi?If not: Are you really sure both PC's have a NIC that can do 100 Mbit or faster? The problem is if one interface is only an old 10 Mbit interface, that will totally slow the connection down. Also: make sure your cables are tip top. Bad cables can cause disturbances on the network and cause degraded performance.

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Re: Network speed?

Post by scorp123 » Fri Sep 28, 2007 7:18 pm

Stretch wrote: I seem to getting round 2.5 - 2.8 MB/s
BTW:

2.5 MB per second = 2.5 x 1024 x 1024 x 1024 Bytes per second = 2'621'440 Bytes per second. And one byte has 8 bits.
2'621'440 Bytes per second = 2621440 x 8 bits per second = 20'971'520 bits per second.
20'971'520 bits per second = 20'971'520 / 1'000'000 Megabits per second = ~roughly 20.9 Mbps.

That's about the speed you'd get in old 10 Mbps 10-Base-2 or 10-Base-T Ethernet networks running at full-duplex (so you can get roughly double the speed between two hosts).

So there is something wrong with your network and / or your network cards.

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Stretch
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Post by Stretch » Fri Sep 28, 2007 8:29 pm

I must take a closer look at this in the morning. I don't know whether transferring via the router is a problem or whether the nics are not right.

I might try a crossover cable between the 2 pc's and see what happens then.

Either way, something ain't right. I tried copying a set of MAME ROMs between the 2 PC's - it took around 20 minutes (17Gig or so). I thought it was because there were so many small files being moved. So I tar'ed them into an archive - but little difference.

Off to bed for now.

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Post by Husse » Sat Sep 29, 2007 12:31 pm

I don't know whether transferring via the router is a problem
Shouldn't be, but again provided decent hardware...
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