Strange network behaviour

[Michael K. Smith]

Vincent Zee <basics at zenzee.cistron.nl> writes:

> I am really at a loss at the moment.
> 
> I have a 100baseT network at home and all connected machines have 100Mb 
> network cards.
> When I upload mp3 files from my ibook to the FreeBSD server the speed 
> drops to 100kb/s.
> 
> This only happens between these two particular machines. These same 
> machines connected to other machines give the expected transmission 
> speeds. I checked cables, switches and router but found nothing 
> unexpected.
> 
> Any hints, ideas or even solutions are most welcome.
> 
> The FreeBSD machine is running 4.7 and the ibook 10.2.4

This sounds a lot like a duplex mismatch. 
Check the collision count.


Hi:

I'm experiencing the same issue from a PowerMac 733 with OS 10.2.4 (which
is, to my mind, pretty FreeBSD like) to several different FreeBSD machines
running 4.5 and 4.7 respectively.  I know there aren't any duplex problems
and I'm not experiencing the issue when I go from either the Mac or FreeBSD
boxes to other hosts.

In doing a TCP dump it looks like packet loss, although it only occurs
between these hosts.  The ack is sent by the Mac but the BSD box doesn't see
it, so the Mac re-acks (up to 4 times usually) before the BSD box acks the
ack at the end of its Window.  Everything slows to a crawl until that one
dropped packet is acked.

Hrmm.   Has anyone else seen this?  I'm thinking it's an issue on the Mac
side, but who knows.

Mike