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Path: utzoo!utgpu!water!watmath!clyde!rutgers!cbmvax!vu-vlsi!devon!paul
From: paul@devon.UUCP
Newsgroups: comp.mail.uucp,news.misc
Subject: Suggestion for a new pathalias cost value
Message-ID: <269@devon.UUCP>
Date: Mon, 25-May-87 16:04:10 EDT
Article-I.D.: devon.269
Posted: Mon May 25 16:04:10 1987
Date-Received: Tue, 26-May-87 04:48:30 EDT
Organization: Devon Computer Services, Allentown, PA
Lines: 65
Keywords: pathalias, maps, uucp, PC-Pursuit
Xref: utgpu comp.mail.uucp:491 news.misc:387


    With the increased use of PC-Pursuit  as  a  (lower  cost)  method  of
    transferring mail and news between systems, perhaps we should consider
    adding a new ``pathalias'' data value that could be used to  denote  a
    PC-Pursuit connection.

    For those of you who haven't read your pathalias documentation lately,
    here  is a list (I hope it's correct!) of the current legal values for
    ``comp.mail.maps'' entries:

	Symbol          Cost            Used to denote
	----------      ----------      -------------------------
	LOCAL           25              local area network
	DEDICATED       95              high speed dedicated (hard wired)
	DIRECT          200             local call
	DEMAND          300             long distance call, anytime
	HOURLY          500             hourly poll
	EVENING         1800            time restricted call
	DAILY           5000            daily poll
	WEEKLY          30000           irregular poll
	DEAD            a very high number  -  non-useable path

    What I'd like to see is something like:

	PCP             900             local call (via PC-Pursuit)

    Perhaps 900 isn't the correct value.  The idea is to have a value that
    is  understood  (by  pathalias)  as  being  less  costly than EVENING;
    perhaps it should be closer to the value of DIRECT.

    To illustrate my  point,  consider  the  following  scenario:   SITE-A
    connects  to  SITE-B using PC-Pursuit, and to SITE-C via a normal long
    distance call.  SITE-C connects  to  SITE-B  through  a  regular  long
    distance  call  also.   So,  the  comp.mail.maps  data  showing  these
    connections would be:

	site-a  site-b(EVENING), site-c(DEMAND)

	site-c  site-b(DEMAND)

    Given these values, pathalias will generate the path  from  SITE-A  to
    SITE-B  as  ``site-c!site-b!%s''  because  the cost using that path is
    DEMAND + DEMAND (600) versus EVENING  (1800).   What  pathalias  isn't
    considering  here  is  that there will be two long distance calls made
    instead of one local call.  Of course, the catch  is  that  PC-Pursuit
    calls  *really  are*  EVENING  calls  during  weekdays  (but  could be
    considered DIRECT on weekends and holidays).

    Now, I realize that my suggestion is only valid if you want  pathalias
    to  generate paths that are the *least costly* (in dollars) to all the
    systems involved along the path.  If you  want  the  *fastest*  (least
    costly  in  time)  path,  the  example above would be correct, even if
    SITE-A listed it's connection to SITE-B  as  PCP  (unless  PCP  had  a
    numeric value less than 600).

    I'd like to see a discussion on this.  If you must flame me, turn  the
    heat down--my asbestos suit is at the cleaners.  :-)

- paul

-- 
Paul Sutcliffe, Jr.	UUCP: paul@devon.UUCP
			-or-  {seismo,ihnp4,allegra,rutgers}!cbmvax!devon!paul

"No problem is so big that it can't be run away from." -- Charlie Brown