Gigabit lan - measuring thruput

[Harry Putnam]

I'm trying to determine how much data I can move over a gigbit segment
of home lan.

I get confused over what is actually supposed to be measured.

Examples are:
Is it 1000 or 1024 bytes per kilobyte?
Is it bytes or bits being measured?

What I actually see, using 1024 divisor is:

2.38 Gb copied over in 77.1 seconds

That works out to 31.85 Megabytes per second I think.

But how would that be reported in gigabit lan terminology.

 

[CWatters]

I'm trying to determine how much data I can move over a gigbit segment
of home lan.

I believe typical ethernet networks achieve no more than 70% of the bit rate
due to protocol overheads so...

10Mbit/s LAN will achieve about 900 KBytes/s max
100Mbit/s ....................9MBytes/s max
1Gbit/s ........................90MBytes/s max

However with fast LANs the performance of the network cards and the systems
they are in start to become limiting. How fast are the disc drives each end
for example.

 

[Larry(LJL269)]

I'm trying to determine how much data I can move over a gigbit segment
of home lan.

I get confused over what is actually supposed to be measured.

Examples are:
Is it 1000 or 1024 bytes per kilobyte?
Is it bytes or bits being measured?

What I actually see, using 1024 divisor is:

2.38 Gb copied over in 77.1 seconds

That works out to 31.85 Megabytes per second I think.

But how would that be reported in gigabit lan terminology.

Its NUGS to use b for bit & B for byte where 8b/B

Western Dig even defines kile=1000 not 1024, Mega=1000000,
etc

Thank God they dont do math in hex!!
HTH-Larry

Any advise given is my attempt to show appreciation for all
the excellent help I've received here but I'm no MVP so it
may only apply NUGS (Normally, Usually, Generally, Sometimes

 

[reader]

I believe typical ethernet networks achieve no more than 70% of the bit rate
due to protocol overheads so...

10Mbit/s LAN will achieve about 900 KBytes/s max
100Mbit/s ....................9MBytes/s max
1Gbit/s ........................90MBytes/s max

However with fast LANs the performance of the network cards and the systems
they are in start to become limiting. How fast are the disc drives each end
for example.

Very late with this response .. sorry.
Thanks CWatters. So if I'm following you here your figures would
indicate my calculations show my lan to be pretty slow compared to
what it should do. I'm seeing 37MB - 50MB per second. The high
points are only about half of what should be happening.

In my case the terminal drives were both wd 250Gb sata drives. Not
sure if SATA drives spin at the 7200 rpm or not. So writing should
not be the bottle neck should it?

The machine doing the copy is a P4 3.2. the other end is
Athlon64 +3400 2.2Ghz.

 

[Bob I]

You are not alone. See last sentence.

http://www.windowsitpro.com/Windows/Articles/ArticleID/24551/pg/5/5.html

"Overall, my tests showed that Gigabit Ethernet provided a tangible
performance improvement, but bottlenecks elsewhere kept the overall
throughput lower than I had hoped. I was satisfied with Gigabit Ethernet
performance relative to Fast Ethernet, and I was particularly impressed
that general network responsiveness remained acceptable even during peak
network loads. But I was disappointed not to be able to reach much
beyond 450Mbps on the Lab's most capable server"