From: clewis@ferret.ocunix.on.ca (Chris Lewis)
Newsgroups: comp.mail.uucp
Subject: Re: Are costs relevant ? (was Re: UUCP map entries)
Date: 17 Nov 92 06:45:03 GMT
Organization: Elegant Communications Inc., Ottawa, Canada

In article <1dtdonINN58c@grasp1.univ-lyon1.fr> Christophe.Wolfhugel@grasp.insa-lyon.fr (Christophe Wolfhugel) writes:
>In article <3983@ecicrl.ocunix.on.ca> clewis@ferret.ocunix.on.ca (Chris Lewis) writes:
>>On the contrary, they're *entirely* relevant. 

>I'm not convinced anymore on that point.  In the design, costs
>are definitely a good stuff, but seeing how they are more
>and more used it does not reflect anymore the reality.

They may not reflect reality, but this doesn't mean that they're irrelevant.
In fact, the problem is that they're relevant, but wrong.  Nor would
any improvement be seen by eliminating costs.  The real improvement
is by getting people to fix their maps, as well as ensure that they're
up-to-date.

>First point: should costs reflect reall costs, delays or a combination of
>both of those parameters ?

>A cheap way may take several days whereas a not much more expensive one
>takes a few hours. I recently had the case with a site in the usa.tx maps
>who had a pathalias route cheap and efficient.

The best way to calculate them is to first determine how often you
connect to your neighbors.  This step is the easy one.  Take that
as a starting point.  Then, factor in:
	- link speed (for small + or - increments)
	- desirability of routing other people's mail thru the
	  link.  If you don't want other people to use the link, but
	  you should be able to, then don't advertise it, just
	  do it in your local maps.
	- reliability - if you go for months at a time only
	  being able to reach them once a week, then say WEEK.
	  Not DEMAND because it's supposed to be, but WEEK
	  because that's how the link sometimes behaves.
	  Take worst-case.
    
There are really no hard-and-fast rules.  There really can't be.

>And...

>... with the recent set of maps posted for Texas, many links have
>changed, and in fact new ones have been added. From a two-hops
>away from the Internet I switched to another two hops away via
>site ks.uucp (at IBM Austin). Too bad, this site is misconfigured and
>all mail get bounced. I declared the site as dead and restarted the
>pathalias. News entry point: another IP site in Texas and 3 or
>4 hops to go to my correspondant.  Another link dead, and that
>still for two or three more turns gave my unefficient routes
>with low cost...

Try sending mail to the postmasters, my experience is that it often
helps to unjam links, or at least to get the map entries fixed.

On the other hand, I often find it more reliable to only run with
local maps (eg: province or state), and select a well administered
machine as smart-host.  I get virtually no bounces from mnie.

>I'm also conscient that changing the current cost scheme would
>be nearly impossible.

To what?  The *real* problem is SAs not keeping their maps up
to date.  Changing the costing scheme won't make any difference.
-- 
Chris Lewis; clewis@ferret.ocunix.on.ca; Phone: Canada 613 832-0541
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