There's a fairly simple reason. This type of compression must keep
latencies from growing too much. This *really* hurts compression.
I see what you mean. However, PPP compression (RFC 1962) should not
have this problem, since the additional time taken to start sending
each packet should be more than offset by the decrease in transmission
time.
depends on which PPP compression algorithm is used. the typical
(for me at least) "BSD compress" algorithm is almost the same
algorithm as the one used in modems. but then again I use
NetBSD. I don't know what compression Mac or Windoze stacks use.
my understanding is that with compressing modems, the main additional
value of PPP compression is in reducing interrupt overhead.
Keith