Subject: Re: your mail
To: Jonathan Stone <>
From: Dave Huang <>
List: current-users
Date: 07/17/1996 17:47:04
On Wed, 17 Jul 1996, Jonathan Stone wrote:
> Bring the PPP connection up again.  Retry whatever-it-is that's
> failing. 

Nothing's actually _failing_, it's just a performance issue... I can get 
around 7.5K/s on incoming ftps, but only 4.9K/s on outgoing ftps.

> PPP includes a link-level checksum.  Watch the packet counts in the
> netstat -I ppp? output over time. Check carefully Check carefully to
> see whether the PPP driver is recording input errors (frames whose CRC
> failed.)  Frames with bad checksums are counted in Ierr field.  A
> non-zero count indicates _something_, possibly overruns, is in fact
> garbling your PPP traffic.  If the packets are being discarded due to
> errors at the PPP level, they'll never even get as far as IP.

No Ierrs or Oerrs at all on my machine, and I don't have access to the
terminal server at the other end of my PPP link, so I can't tell whether
it got any errors. 

> Also, use netstat (or an SNMP daemon and monitor, if you prefer)
> to watch the rate of change of bad packets at the IP and TCP level.
> I run "netstat -p ip" "netstat -p tcp".  One has to manually compute
> the rate of change; netstat's -i option means something different
> to, say, vmstat's.   (Adding  periodic  sampling and rate-of-change
> to netstat would be a Cool Project.)

I'll take a look at netstat -p ip later (not running NetBSD right now), 
but I did look at netstat -p tcp, and the only thing that seemed unusual 
was a large number of data packets retransmitted.

> What OS is your FTP peer (ghostwheel) running?  Is it a pre-2.0.0
> Linux? If so, have you tried turning off rfc1323 on your NetBSD
> machine??

ghostwheel is running BSD/386 1.1, and is on an ethernet with the 
terminal server I get my PPP connection from. I don't have a PPP 
connection directly between my machine and ghostwheel, so it's hard for 
me to tell exactly what it's not liking about my packets :)

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