Xref: utzoo comp.mail.uucp:1021 news.sysadmin:554 Path: utzoo!utgpu!water!watmath!clyde!rutgers!cmcl2!husc6!hao!gatech!hubcap!ncrcae!ncr-sd!greg From: greg@ncr-sd.SanDiego.NCR.COM (Greg Noel) Newsgroups: comp.mail.uucp,news.sysadmin Subject: Re: Problems with pathalias Message-ID: <2057@ncr-sd.SanDiego.NCR.COM> Date: 21 Feb 88 03:51:29 GMT References: <590@acornrc.UUCP> Reply-To: greg@ncr-sd.SanDiego.NCR.COM (Greg Noel) Organization: NCR Corporation, Rancho Bernardo Lines: 46 I can only help with one of the problems described here, so I waited to see if anyone could help him with both of them. Since nobody has, I'll explain the one that I can and hope someone else will offer the other. In article <590@acornrc.UUCP> bob@acornrc.UUCP (Bob Weissman) writes: >I've been having problems with pathalias lately. .... >Site 'iconet', for example, disappears without a trace .... I can't help with this problem; not enough information. >We talk to a site, orc.olivetti.com, which is not yet listed in the >official maps, so it appears in our path.local file thusly: > acornrc (DIRECT+FAST) > orc = orc.olivetti.com > orc .orc.olivetti.com He then observes that, although pathalias constructs a direct route to orc, it constructs a long path to the domain: > orc orc!%s > .orc.olivetti.com oliveb!orc!%s If you think about it, this is not a surprise. What the input says is that you can reach .orc.olivetti.com by going through orc, but that you shouldn't go directly through orc. Pathalias does this by creating a dummy node for the arc to , a node which has no neighbors. The domain name is just another node to pathalias, so it makes it a neighbor of the "real" orc. Thus, the path to the domain does not go through the dummy ; in our example, it is oliveb!orc!.orc.olivetti.com!%s and in the post-processing for the output paths, names beginning with a dot are stripped out, giving the counter-intuitive output. The solution is to coerce pathalias into constructing links from the dummy s to any other node that will engender a null output path. It would be ideal if pathalias would do this automatically, but I don't see any easy way of doing it; I can hear Peter screaming already. It might be possible to allow a specification like " .orc.olivetti.com" but that would be a manual and error-prone operation -- everybody who was the destination of a non-through-path link would have to know to include it. The real pity of this is that it negates a lot of the value of a link to uunet, since they list most (all?) of their links as non-through-path, so a gateway that signs up for better connectivity for their domain actually receives the benefit only for themselves and not for the whole domain.... -- -- Greg Noel, NCR Rancho Bernardo Greg.Noel@SanDiego.NCR.COM or greg@ncr-sd