Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!shadooby!oxtrap!mudos!Marc.Unangst
From: mju@mudos.ann-arbor.mi.us (Marc Unangst)
Newsgroups: comp.mail.uucp
Subject: Re: New UUCP Protocol (was: Re: Zmodem added to UUCP)
Message-ID: <672.2530C0D4@mudos.ann-arbor.mi.us>
Date: 9 Oct 89 13:11:04 GMT
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In article <1989Oct9.003603.3693@esegue.segue.boston.ma.us>, johnl@esegue.segue.boston.ma.us (John R. Levine) writes:
 >PEP, though, is really a
 >half-duplex protocol, and fakes full-duplex by turning the line around.  That
 >means that the zmodem ACK packets cause a performance hit and spoofing would
 >still be a win.

Sigh.  This is why we want Zmodem -- Zmodem is a streaming ACKless protocol.
The only time a receiving Zmodem sends anything back to the sender is if
it gets a bad block, or at the end of each file.

In addition, Zmodem adapts dynamically to noisy lines -- It drops the
packet size if it gets a lot of errors, and then will bring it back
up (eventually) if it stops getting line hits.

--
Marc Unangst
Internet: mju@mudos.ann-arbor.mi.us
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