Subject: Re: What is best, PPP or Slip?
To: Michael Graff <>
From: Bill & <>
List: current-users
Date: 08/05/1994 08:53:30
> You may get better overall speed unless you don't care about interactive
> traffic and you never loose a packet.  Assuming no compression and perfect
> transfer rates, you'll get 1440 char/sec.  That means a 1500-packet would
> be over a second to send.  So, if 10 of those are queued up before your
> small interactive-typing ones, you may wait a while.

Actually, No, you won't, because the CSLIP in NetBSD implements
priority queueing based on the IP TOS bits.

Given header compression (which, on a good day, shrinks the 40 byte
IP+TCP header down to 4 bytes) the difference in efficiency between
1500-byte and 250-byte packets is negligable.  With 1500 bytes of
data, you send 1504 bytes over the serial line with a 1500 byte MTU,
vs 1524 with the 250 byte packets; that's about a 1% difference..

The big advantage of the smaller MTU's is that smaller, high priority
interactive traffic like telnet can get in ahead of the bigger lower
priority stuff like FTP data more quickly..