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From: hhs@hou2h.UUCP (H.SHARP)
Newsgroups: net.dcom,net.lan
Subject: Re: Re: Standards for commercial packet radio
Message-ID: <1035@hou2h.UUCP>
Date: Wed, 28-Aug-85 10:32:40 EDT
Article-I.D.: hou2h.1035
Posted: Wed Aug 28 10:32:40 1985
Date-Received: Fri, 30-Aug-85 08:11:09 EDT
References: <501@petrus.UUCP>
Organization: AT&T Bell Labs, Holmdel NJ
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Xref: watmath net.dcom:1212 net.lan:996


>From: karn@petrus.UUCP (Phil R. Karn)
>Posted: Tue Aug 27 19:44:57 1985

>True, it's also at least theoretically possible to use larger packet and
>window sizes in X.25 but no one seems to know how to do that with the actual
>PDN we have to deal with.

>I think best way to understand the X.25/CCITT mentality is to understand
>that it's just fine for what almost everybody uses it for -- remote access
>from a dumb terminal through a PAD. Relatively few people are doing the kind
>of true host-to-host resource sharing that is the basis of the Internet.

It is interesting to consider another viewpoint of this matter.
Recommendation X.25 and the ISO standard for X.25 for 1984 
make allowances for packet sizes up to 512 octets (or 1024 octets).
The PDN's are only implementing the smaller packet sizes (128 octets)
because the only demand is for remote access from a dumb terminal
through a PAD.  Maybe if the PDN's had more demand for true
host-to-host resource sharing, they would offer the larger packet
sizes and faster lines.  Any comments from a PDN out there?
 
If a switch can handle a certain number of packets per second, then
increasing the packet size will increase throughput (of course, other
factors come into play, such as need for more buffer space).