On Sun, 28 Feb 1999, John Corey wrote:
> Subject: Collisions
>
> I've got these Tulip 100baseT ethernet cards here at home. Whenever I
> transfer fairly large files, the collision light on my hub goes crazy.
> I can still transfer at about 2 MB per second, which is plenty fast, but
First point: use 'ttcp' in each direction to check the stream throughput.
FTP tests the filesystems more than the network.
> it's been bugging me. It does this in communication with another Linux
> box or a Win98 box, over either HTTP, FTP, or SMB. On the otherhand, I
> can send a ping flood across, and the collision light only comes on
> sporadically, with no packet losses.
Flood ping waits a bit for a reply before sending the next packet.
This misleadingly minimizes collisions.
Ping also
doesn't check for available buffer space it preloads packets.
reports "N packets transmitted", even if no ARP reply was received.
It's fine as an initial functionality test, but it's pretty much misleading
when it comes to diagnosing network performance or errors.
> I'm not even sure where to look for this. Since it happens with several
> protocols, I'm guessing somewhere in the kernel area. Or is there
> something that might need set with the card's (dos only, of course)
> setup program?
A comon problem is a host forcing full duplex when connected to a repeater
(some manuals imply that it magically doubles performance) but I don't think
that's occuring here.
Donald Becker [EMAIL PROTECTED]
USRA-CESDIS, Center of Excellence in Space Data and Information Sciences.
Code 930.5, Goddard Space Flight Center, Greenbelt, MD. 20771
301-286-0882 http://cesdis.gsfc.nasa.gov/people/becker/whoiam.html
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