Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!apple!agate!ucbvax!MATHOM.CISCO.COM!BILLW
From: BILLW@MATHOM.CISCO.COM (William "Chops" Westfield)
Newsgroups: comp.protocols.misc
Subject: Re: SLIP: Why are people so reluctant to use it?
Message-ID: <12631113857.26.BILLW@mathom.cisco.com>
Date: 19 Oct 90 21:00:43 GMT
References: <130675@pyramid.pyramid.com>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 21


    PPP is really just HDLC asynchronous. A proper implementation is
    complex, and can be a real CPU hog. Were I to write from scratch, I'd
    need about 6 weeks, and I'm an HDLC expert. Present PD versions are
    little more than toys; I don't know who/when someone is going to write
    a better version that they are willing to give away. (Pyramid's
    version, if done at all, would be based on priority HDLC code that we
    already have.)

I don't think you understand PPP.  It uses HDLC framing, but does not have
a lot of the other baggage that goes along with HDLC.  (In particular, it
does NOT do retransmission or assure reliable delivery.)  A simple
implementation of PPP (direct SLIP replacement - eg ignore most of the
option negotiation) should take considerably less than 6 man-months.
It should not be that much of a CPU hog, either - the time spent doing
the CRC is software (for async) is easilly outweighed by the interrupt
processing overhead...


BillW
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