Path: utzoo!utgpu!attcan!uunet!husc6!cmcl2!rutgers!njin!brisco From: brisco@pilot.njin.net (Thomas Paul Brisco) Newsgroups: comp.mail.uucp Subject: Re: re/routing (was: why you should say "-d ru) Message-ID: Date: 5 Aug 88 15:45:55 GMT References: <676@bacchus.DEC.COM> <881@vsi1.UUCP> <3674@palo-alto.DEC.COM> Organization: NJ InterCampus Network, New Brunswick, N.J. Lines: 122 ] = vixie@palo-alto.DEC.COM (Paul Vixie) <3674@palo-alto.DEC.COM> > = lmb@vsi1.UUCP (Larry Blair) <886@vsi1.UUCP> } = kehres@tis.llnl.gov (Tim Kehres) <22350@tis.llnl.gov> ]This depends on what you mean by "all your routing". What I mean by "all my routing" is all my routing. I only have to say "rutgers!foo!user" and let the rutgers mail look up the path to site foo. So, it literally does *all my routing*. (I don't know how else to say it). >I have NEVER heard a single good >reason for a site to reroute. Rerouting saves the offending site nothing. >In fact, they end up having to process the same mail twice when it bounces! >[That is a perverse justice] This is more than a perverse justice. Isn't it logical to you that if site A talks to site B then we can infer that site B talks to site A? (I've heard rumors that there is a theory stating that they both also talk with the same bandwidth, but I'm not sure that it's been proved yet ;-) I'm not sure what site you mean by ``the offending site'', but I believe that rerouting is a big win for all sites involved. Let's assume that there exists the following links: A -> B (local, 9600 baud, direct) A -> C (long distance, 1200 baud, daily) B -> C (long distance, 9600 baud, hourly) The obvious thing for the casual user (on A) to send a letter to a user on C to do is to route a letter thus: C!user. The routing mechanism should give the route B!C!user. In this case it is not obvious that C!user is not an optimal path. Not only is it not an optimal path, it might be more expensive. Since site A only polls site C on a daily basis, we should assume that site A is unwilling to spend the money for the phone call very frequently. However, site B has stated that it is willing to spend more money on the cause. Since site B is willing to pay the price for a "better" connection (and has advertised it), then it is only logical to use such a path. However, of course, without a routing mechanism that does "stupid" things like this, we would incur a higher cost and slower speed by waiting around at site A for the poll to B, whereas the path via site C is certainly cheaper (from A's point of view). Of course this is a black-and-white example and obviously contrived - but is not unrealistic. ]If I send to <...!rutgers!foo!bar!person>, and rutgers looks in its map ]database and says "oh, site <<>> can be reached through ...!baz!bar!user", ]IT HAS JUST DONE THE WRONG THING. Since we are arguing here about what *is* the right thing I'm not sure what this statement means. ] is never nec'ily the same person as . <<>> ]can be contextual: and aren't nec'ily the same machine. ] baz!bar!user foo!bar!user ^ ^ | | +-------------------------------+ What the maps and registry are for is to ensure that they *ARE* the same hosts, and consequently the same user. Looks like you've been bit by the people that I was flaming originally. Either baz or foo are advertising a black hole and should fix their maps. According to the maps, it is *not* doing a `wrong thing', but is only reflecting the bogosity in the maps written by either the administrator at site foo or site baz. } o Optimal source routing can be dynamic and the originator/recipient } cannot always determine best routing. } } o Most users are only concerned about getting their mail through, } not how it gets there. When is the last time you specified the } route the postal service should use to get a letter delivered? } How many of your users can tell you the best route to mcvax } without looking through past mail messages or uucp tables? } ... } }These are probably not the only reasons, but enough to make the point. }There is sometimes a tradeoff between best routing and making the use of }electronic mail possible for a wider range of users. Although pathalias }(or the data that gets fed into pathalias) certainly can be improved, it }does help (most of the time) in generating good paths, and provides some }isolation to a wide range of users to routing decisions. (thanks, Tim). The only thing I've seen so far is that if you don't care enough about the net to keep your maps updated, or complain to the people who don't keep their maps updated, OR simply prefer to do the wrote/repetitive tasks that computers were designed for (like figuring out a path between site foo and baz) - then you should not use the routing information available to you. It seems that if we lived in the "best of all possible worlds" (i.e. where all admins kept their maps updated) then the arguments that I've heard would fall to the ground. If you choose to mark rutgers dead (and it sounds like you'll be marking mcvax dead soon, too), I'm sure they'll be very happy to not have your mail passing through their machines. vixie's and lmb's arguments sounds as if they want to cure the symptoms, not the disease. I must infer that if you get a ticket (or whatever) for breaking a law that you don't agree with - then you flame on the cop, not on your government officials. Yes - it is very frustrating to have a letter disappear down a black hole. I do not, however, think that this means that I should do my routing by hand - I tend to blame the person advertising a bogus route. Tp. -- ---------------------------------------- UUCP: ...!rutgers!brisco ...!njin!brisco ARPA: brisco@pilot.njin.net BITNET: brisco@zodiac.bitnet Voice: (201) 932-2351 ---------------------------------------- Ask me about the New Jersey Intercampus Network Pilot Project