paul@devon.UUCP (05/25/87)
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 Brownbblue@crash.UUCP (05/29/87)
In article <269@devon.UUCP> paul@devon.UUCP (Paul Sutcliffe Jr.) writes: > > 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. ... > What I'd like to see is something like: > > PCP 900 local call (via PC-Pursuit) Oh, heavens no! First, even though PCP is low cost in terms of dollars, does not make it low cost in terms of delivery times. It is an after 6pm weekdays, and 24hour weekends connection - that right there makes it hard to value because pathalias has no idea of day distinctions. But worse, even though you can *use* it after 6pm and on weekends does not mean you can get through! There are horrendous bottlenecks in certain areas using PC Pursuit. These bottlenecks can further delay mail by hours on end. And unless you've done some tweaking to your uucp (WINDOWS = 7, or use the f protocol), throughput when you do finally connect is around 600bps. Since the pathalias values are supposed to assess the cost of delivery both in terms of real cost *and* delays encountered, the combination of all of this makes for an EXPENSIVE connection. If anything, under average (non optimized and non-idea connectivity) conditions, the pathalias cost should be HIGHER! In my opinion, at the very least EVENING is generous for PCP use. Under optimized conditions where connectivity is first-call (or close) and throughput is high (via the modifications mentioned above) you could say EVENING+HIGH (yielding 1795) or subtract some other number that you feel more closely approximates a realistic cost (maybe EVENING/2 or something). But do it on a PER CONNECTION basis, taking into consideration what the real delays and connection costs are for that particular connection. Assigning some new (cheap) PCP value would be a disaster. I have been using PC Pursuit for over a year now, from San Diego to San Francisco, Denver, Los Angeles, Atlanta, Boston and Chicago. At times I have to poll manually during the day because mail queued for one of these areas couldn't get delivered ALL NIGHT! That doesn't sound like bonus time to me... --Bill