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From: larry@pdn.paradyne.com (Larry Swift)
Newsgroups: comp.dcom.lans
Subject: Re: What services does X.25 provide?
Keywords: x.25, services, login, e-mail, file transfer, IPC
Message-ID: <6576@pdn.paradyne.com>
Date: 22 Sep 89 14:03:16 GMT
References: <796@maxim.erbe.se> <3279@wasatch.utah.edu> <522@wet.UUCP> <1989Sep18.020822.16329@cit5.cit.oz> <727@idacom.UUCP> <17683@bellcore.bellcore.com>
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Reply-To: larry@pdn.paradyne.com (Larry Swift)
Organization: AT&T Paradyne, Largo, Florida
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In article <17683@bellcore.bellcore.com> karn@jupiter.bellcore.com (Phil R. Karn) writes:
    Telenet's network seems to act as though the D-bit were always set. That
    ...
    the end-to-end RRs means that the maximum achievable throughput over a
    single virtual circuit can be abysmal. This results in hacks like
    "downward multiplexing", where a datagram-based DTE (e.g., the CSNET
    IP-on-X.25 gateway) opens multiple virtual circuits to the same
    destination and spreads its datagrams among them.  It often takes 4 or 5
    parallel virtual circuits to keep a single 9.6kb/s access link busy.
	...
    Face it, X.25 is a disaster for anything other than remote slow speed
    terminal multiplexing. It is not suitable for serious computer
    networking.
    
Seems like a quantum leap from an obvious hack to a blanket condemnation
of X.25.  It would be easy (and obvious?) for a private X.25 network to
open the window size to a more optimal value based on number of hops.

Larry Swift                     larry@pdn.paradyne.com
AT&T Paradyne, LG-132           Phone: (813) 530-8605
8545 - 126th Avenue, North
Largo, FL, 34649-2826           She's old and she's creaky, but she holds!