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From: rb@ccivax.UUCP (rex ballard)
Newsgroups: net.news
Subject: Re: The cost of a message
Message-ID: <368@ccivax.UUCP>
Date: Sat, 1-Feb-86 00:30:13 EST
Article-I.D.: ccivax.368
Posted: Sat Feb  1 00:30:13 1986
Date-Received: Wed, 5-Feb-86 00:43:49 EST
References: <2501@amdahl.UUCP> <871@vortex.UUCP> <2963@glacier.ARPA>
Reply-To: rb@ccivax.UUCP (Rex Ballard)
Organization: CCI Telephony Systems Group,  Rochester NY
Lines: 89

In article <2963@glacier.ARPA> reid@glacier.UUCP (Brian Reid) writes:
>Forward computation: assume that...
>N=4000		Number of nodes on USENET
>C=1.5		Average redundant connectivity of a USENET node
>K=0.10		$US per minute for long-distance telephone time
>L=0.02		$US per minute for local telephone time
>S=80		Characters per second average throughput
>P=1000		characters in a news message
>4000*0.02*1000/(60*80) = $16.66 per 1000-character message.
>Pessimistic computation (all telephone calls long-distance; 50% redundant
>connectivity). This is N*C*K*P/(60*S), which is 4000*0.10*1000*1.5/(60*80),
>or $125 per 1000-character message.
>I think that a reasonable model...that 10% of the phone calls are long distance
>This gives us the hybrid formula
>   COST = 0.9*(4000*0.02*1000/(60*80)) + 0.1*4000*0.10*1000*1.5/(60*80)
>or COST = 14.94 + 12.50 = $27 for a 1000-character message.
>Backward computation:
>That would result in a figure of $32 per 1000/character message.

Two possible solutions here:

Reduce Cost Per Message:

1:	Crunching or compressing data might save 10-50%.
	COST = 4000*0.10*1000*1.5/(60*80*2) = $62.50 (worst case)

2:	Trellis coded modems have an average throughput of 960
	characters per second (With reliability checks). This could cut
	costs by a factor of ten, work on any two wire phone, and
	require simple RS-232 connections.
	COST = 4000*0.10*1000*1.5/(60*960) = $10.42 (worst case)
	COST = 4000*0.02*1000*1.5/(60*960) = $2.08 (best case)

3:	ISDN modems, average throughput 5000 characters per second, available
	as leased lines, through PBX, or ISDN carriers - could cut costs to
	back-bone sites to 1% of original cost.  Only systems with this
	capability should be back-bone sites.
	COST = 4000*0.10*1000*1.5/(60*5000) = $2 (worst case).

	Adding compression may or may not reduce 2 and 3 further

Reduce traffic:

1:	Reduce "Macro Expansion" - cross-postings, use of RCS-style
	'diff -e' of previously posted articles, ability to cross reference
	articles.  Links between articles, and tar with compression could
	reduce the duplication associated with 'bad habits' and stimulate
	interest between groups.

2:	Traffic controls.  Such tactics as requiring 'spell', deleting
	newsgroups, moderated feeds, and groups have all been suggested
	as ways to 'make it harder to post an article' and make the net
	less of a 'political forum'.  Perhaps distribution menus, and
	routing of responses would help as well.

3:	Message concentration/distribution - should articles be posted via
	ucbvax!allegra!siesmo!rochester!ritcv!..... if they could be posted
	via ucbvax!siesmo!ritcv ?  Better subnet addressing would help.

4:	Mailing Lists - for some reason, there are a number of 'mailing lists'
	which are really 'newsgroups' but get distributed in the worst
	possible way, via mail.  Instead of making it harder to
	start/post newsgroups, it should be made easier.  Imagine 200
	identical letters going to the same machine via the longest
	possible path.  Info-mac and info-atari or whatever they are
	called are just two good examples of these 'underground nets'.
	ARPA point to point drops are another example of potential
	wastes.

5:	Encourage (build in to news) local networking.  Local traffic
	is already light, but providing a full compliment of distribution
	to a hierarchy of local networks (Site,Company,City,State,
	country,world) would allow posting of information, discussion
	at a local level.  Provide a 'long name to net name' translation
	directory that users could use for setting distribution.  Sort
	of a network version of 'finger'.

6:	Selective Follow-up.  When a 'info-wanted' type of message come
	in, have a method of sending a reply to the host of the requester.
	If another person reading the 'info-wanted' would also like to
	see the responses, a 'get more info' could be sent.
	Each follow-up could be sent 'back up' by the machines that
	have that info.

Computer traffic management is not that much different than automobile
traffic management.  Build expressways where the traffic will be heavy
so the side streets won't be filled with cars.

Hope this was of some use to somebody.