I have been running NetBSD-current for some time, and recently noticed
an odd situation.  I was FTPing a file from one part of my ISPs LAN to
another from my box (on the end of a dedicated PPP link) to one of the
boxes on the ethernet (through a Livinston Portmaster).

When I am transferring files TO cynjut, I generally have very few
problems:  I regularly get transfer rates higher than 28.8K.  

When I transfer files FROM cynjut, I get good throughput for a while,
then the modem just hangs up.  It redials, tries to connect and fails.
The next time the modem redials, I get in just fine.  The transfer
continues as soon as the PPP link is estabnlished and continues for as
little as a second and as long as a couple minutes.  The cycle is then
repeated (dies, dials, fails to log in, redials, connects).  The entire
cycle time for this is less than the time out for an FTP connection, so
the connection remains and the files are transferred normally.  The
problem is easily reproducable.  All I have to do is try and transfer
the kernel from cynjut to another machine.

I saw something like this in either news or here a couple weeks ago, and
thought it might be familiar.  I got looking and it appears to be
exactly what is happening here.  If there are any suggestions available,
I'd love to hear them....

Some particulars:

NetBSD cynjut.neonramp.com 1.2_ALPHA NetBSD 1.2_ALPHA (CYNJUT) #5: Mon 
Jun 10 20:48:38 CDT 1996     
burgess@cynjut.neonramp.com:/usr/src/sys/arch/i386/compile/CYNJUT i386

The modems on both ends are USR Sportsters.  Here is the output from an
'ATI3':

USRobotics Sportster 33600 Fax Settings...

   B0  E1  F1  L2  M1  Q0  V1  X4  Y0
   BAUD=115200  PARITY=N  WORDLEN=8
   DIAL=HUNT   ON HOOK

   &A3  &B1  &C1  &D2  &G0  &H1  &I0  &K1  &M4  &N0
   &P0  &R2  &S0  &T5  &U0  &Y1  

   S00=000  S01=000  S02=043  S03=013  S04=010  S05=008  S06=002
   S07=060  S08=002  S09=006  S10=014  S11=070  S12=050  S13=000
   S15=000  S16=000  S18=000  S19=000  S21=010  S22=017  S23=019
   S25=005  S27=000  S28=008  S29=020  S30=000  S31=128  S32=002
   S33=000  S34=000  S36=014  S38=000
 
A representative entry from the ppp error log:

Jul 21 06:15:43 cynjut pppd[3957]: Modem hangup
Jul 21 06:15:43 cynjut pppd[3957]: Connection terminated.
Jul 21 06:15:44 cynjut pppd[3957]: Exit.
Jul 21 06:15:44 cynjut pppd[4035]: pppd 2.3.0 started by root, uid 0
Jul 21 06:16:30 cynjut pppd[4035]: Connect script failed
Jul 21 06:16:31 cynjut pppd[4035]: unable to delete pid file: Is a directory
Jul 21 06:16:31 cynjut pppd[4035]: Exit.
Jul 21 06:16:31 cynjut pppd[4038]: pppd 2.3.0 started by root, uid 0
Jul 21 06:16:52 cynjut pppd[4038]: Serial connection established.
Jul 21 06:16:53 cynjut pppd[4038]: Using interface ppp0
Jul 21 06:16:53 cynjut pppd[4038]: Connect: ppp0 <--> /dev/tty02
Jul 21 06:16:55 cynjut pppd[4038]: local  IP address 204.248.20.49
Jul 21 06:16:55 cynjut pppd[4038]: remote IP address 204.248.22.129
Jul 21 18:13:05 cynjut pppd[6963]: unable to delete pid file: Is a directory
Jul 21 18:13:05 cynjut pppd[6963]: Exit.
Jul 21 18:13:05 cynjut pppd[6966]: pppd 2.3.0 started by root, uid 0
Jul 21 18:13:25 cynjut pppd[6966]: Serial connection established.


-- 
Dave Burgess  (The man of a thousand E-Mail addresses)
*bsd FAQ Maintainer / SysAdmin for the NetBSD system in my spare bedroom
"Just because something is stupid doesn't mean there isn't someone that 
doesn't want to do it...."