Subject: Re: problems with ppp
To: None <>
From: Mike Long <>
List: netbsd-users
Date: 09/25/1995 09:58:09
>Date: Mon, 25 Sep 1995 09:58:02 +1000
>From: bryan collins <>

>I'm running at mtu of 256, it was running at 256 on a
>linux machine with the same modem, same terminal server
>at other end, and same configuration, just that pppd is
>on netbsd now, and the performance is horrible, I get
>around 300bytes/sec in transfers like ftp/http whereas they
>went upto 5.7k/2.6k repsectivley with ppp on linux.

Some things to try:

1) Upgrade to -current; -current's com.c driver is much better than
the one in 1.0.  pppd in -current is also newer and (I presume)

2) Increase the mtu/mru; I use the defaults (1500) for both.
Increasing the mtu and mru decreases TCP/IP overhead, giving you
better throughput.

3) Use 'asyncmap 0x0' to eliminate control-character-quoting

Optimizations like these allow me to get ~1630 chars/sec FTP transfers
over a 14.4kbps w/V.42+V.42bis modem.  My ISP uses Livingston
Mike Long <> 
VLSI Design Engineer         finger for PGP public key
Analog Devices, CPD Division          CCBF225E7D3F7ECB2C8F7ABB15D9BE7B
Norwood, MA 02062 USA                assert(*this!=opinionof(Analog));