I've got a NetBSD PC (K6-2 500, 256 meg RAM, twin Intel Etherexpress
PRO/100+ NICs) that does some firewall/NAT amongst other things for
a Linux PC (PII-450, 3com 905b, 128 meg RAM).  They are on a 
100baseT switch, both NICs configured to full-duplex, with the
Linux PC using 3Com's NIC driver.  Both have IDE disks.

netperf & ttcp say I am getting 93+ Mbps between these computers,
even for long tests (a few minutes). This is for both TCP & UDP.
Running these at the same time on both I get 90+ Mbps each way
for UDP, so full-duplex seems to be working fine.

FTP & NFS tell a different story - moving a large file (100 meg)
between them starts at 9 or so Mbyte/sec and then slowly drops
to about 2.5 Mbyte/sec where it stays until its finished.  Copying
a bunch of MP3's gives varying results - some will go at 10 Mbyte/s,
others about 1 or 2.  Same for NFS.

Any ideas why the FTP & NFS speeds would do this, or why transfer
speeds are so inconsistent, even under very light loads for 
both?  I've tried the stock NetBSD ftpd as well as wu-ftpd, and
wu-ftpd and proftpd on the Linux PC, but the results were the 
same.  Ditto for ncftp vs. ftp.


Thanks,

Brian