Slow copy over cross cable


G

Guest

I've connected my 2 XPs using cross over cable, connection speed is 100 Mbps.
When I copy file, why utilization is running around 50%, why don't it 100%
utilization?
 
Ad

Advertisements

B

Bob Willard

Kong said:
I've connected my 2 XPs using cross over cable, connection speed is 100 Mbps.
When I copy file, why utilization is running around 50%, why don't it 100%
utilization?
When you measure STR (Sustained Transfer Rate) across a net, make sure you
are using one large file (large enough to calculate STR using a watch),
instead of a bunch of small files, so that the per-file overhead does not
affect the STR.

Make sure both NICs are set for FDX, since HDX will reduce STR. And, check
the network params, esp. MTU and RWIN, on both NICs. Use the biggest MTU
that does not cause fragmentation (hint: PING -f), and a large RWIN.

Note that, even with the same copy procedure (e.g., copy'n'paste to a
mapped net drive), there are four ways to do the copy: push from PCa to PCb
push from PCb to PCa, pull from PCa to PCb, and pull from PCb to PCa.
And, you might see four different STRs.

With net file copy, STR can be limited by several factors in either PC,
other than the network, including: slow CPU, not enough RAM, and slow HD.
With older PCs, the HD is a likely suspect.

For reference, I get 9-10 MB/s copying a large file with a mapped net drive
between reasonably fast XP PCs. I don't have a crossover cable -- my
network has a central WRT54G router/switch which should be slightly
slower than a crossover cable.
 

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments. After that, you can post your question and our members will help you out.

Ask a Question

Top