nanog mailing list archives

Re: And we thought the text part of the Starr Report would be bad


From: miquels () cistron nl (Miquel van Smoorenburg)
Date: 19 Sep 1998 22:39:15 +0200

In article <199809182139.RAA10174 () us net>, David Stoddard  <dgs () us net> wrote:
      There is more to this than meets the eye -- 28.8K is asynchronous
      and has start and stop bits for every byte, so there are a maximum
      of 2880 bytes/sec available over 28.8K.  Then there is the issue

Almost every modem supports V42 error correction, which makes the modems
speak a sort of synchronous with each other (actually data is transmitted
in blocks with a start-of-block and end-of-block marker, and a checksum).
That gets you 8 bits in a bith minus some negligeble V42 overhead.
So an 28k8 modem can actually transfer almost 3.6 Kbytes/sec.

Because of the block-oriented approach you do get a bit higher latency
on interactive connections, which is why gamers often turn of V42.

Somehow, nobody seems to know this.

Mike.
-- 
  "Did I ever tell you about the illusion of free will?"
    -- Sheriff Lucas Buck, ultimate BOFH.


Current thread: