North American Network Operators Group
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Re: And we thought the text part of the Starr Report would be bad

  • From: John Leong
  • Date: Tue Sep 22 14:36:19 1998 
> As long as we are being specific about this, I omitted data
> compression too

V42bis compression is probably not very useful if the data is already
compressed either at the application level [gif, tiff, mpeg] or at PPP.

By the way, V42 [LAP-M] does not just add frame overhead.  It is a full
blow error correction and flow control protocol and as such can add
sizable retransmission delay if the link is noisy and SREJ [selective
reject ... similar in concept to TCP SACK] is not used.  Note that it is
a bit of an irony that even though an application decide to use UDP
because it specifically do not need or even want flow control and error
correction, componenet in the path such as the modem will go ahead and
do it anyway :-(

Regards,
John