Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!uunet!telebit!brian
From: brian@telebit.com (Brian Lloyd)
Newsgroups: comp.dcom.modems
Subject: Re: Cost of 9.6/19.2 kbps leased line from Bay Area to Midwest
Message-ID: <1991Apr16.052618.29943@telebit.com>
Date: 16 Apr 91 05:26:18 GMT
References: <9104141911.AA04797@ahkcus.org> <1991Apr15.191317.8465@nstar.rn.com>
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In article <1991Apr15.191317.8465@nstar.rn.com> larry@nstar.rn.com (Larry Snyder) writes:
>Currently we are running stock SLIP from Interactive Systems
>and have plans to upgrade to PPP slip which should increase
>the throughput..

Actually PPP as a protocol will not net you any improvement in
performance over SLIP.  In fact, switching from SLIP to PPP will
reduce your throughput slightly because PPP has more overhead (3 to 6
octets per frame depending upon which LCP compression option you have
negotiated).  If you are running IP only and you are running over a
leased line and you are using an async interface to your modem, there
is no advantage to switching to PPP.

PPP is a win when you are running on a sync link because almost all of
the router manufacturers now support PPP as a link protocol.  PPP is
also a win if you are running on a dial-up link because of the
authentication and IP address negotiation/assignment features.

If you are looking for performance consider running Van Jacobson's
IP/TCP header prediction/compression known as CSLIP.  Some
implementations of PPP also support VJ compression.




-- 
Brian Lloyd, WB6RQN                              Telebit Corporation
Network Systems Architect                        1315 Chesapeake Terrace 
brian@napa.telebit.com                           Sunnyvale, CA 94089-1100
voice (408) 745-3103                             FAX (408) 734-3333