gws2@cblpf.ATT.COM (Gary Sanders) (10/15/87)
Here is one for all you uucp/uucp map guru's.. I was rummaging
through the maps and started running "cost" values from differnet
sites and found an interesting item..
We have the following sites, A=cbosgd
(all from ohio map) B=osu-eddie
C=chemabs
D=n8emr
Number is "()" are link values.
(500)
A-------B
(200) | |(200)
| |
D------ C
(5000)
From the uucp maps, A talks to B, B talks to A
B talks to C, C talks to B
D talks to C, C talks to D
D talks to A A Doesn't talk to D (according to maps)
Pathalias says that the shortest path from A to D is A!B!C!D
Why? Dosent pathalias take into effect that D talks to A???
Does pathalias take only into account info from the "FROM" site??
--
Gary W. Sanders {cbosgd|ihnp4}!gwspc!gws AT&T Bell Labs (Columbus)
72277,1325 (cis) N8EMR @ W8CQK (packet)
614-860-5965 (w) 614-457-4595 (h)jbs@eddie.MIT.EDU (Jeff Siegal) (10/16/87)
In article <771@cblpf.ATT.COM> gws2@cblpf.ATT.COM (x5965) writes: >[...] > D talks to A A Doesn't talk to D (according to maps) > >Pathalias says that the shortest path from A to D is A!B!C!D >Why? Dosent pathalias take into effect that D talks to A??? It will use the reverse link (A-->D), but only if there is no other possible path. If you want mail to be routed over a link in a particular direction, you need to list that as a path in the map. Jeff Siegal
brian@ncrcan.Toronto.NCR.COM (Brian Onn) (10/16/87)
In article <771@cblpf.ATT.COM> gws2@cblpf.ATT.COM (x5965) writes: >Here is one for all you uucp/uucp map guru's.. > [nice picture deleted] >Pathalias says that the shortest path from A to D is A!B!C!D >Why? Dosent pathalias take into effect that D talks to A??? >Does pathalias take only into account info from the "FROM" site?? Pathalias does realize that A talks to D. It gets this information from the entry for site D, since that says D talks to A. However, since it is not listed in A's entry that A talks to D, pathalias assumes that the connection cost from A to D is arbitrarily high, I think around 30000 or so. Thus the cheapest path according to the given information is A!B!C!D. -- +-------------------+--------------------------------------------------------+ | Brian Onn | UUCP:..!{uunet!mnetor, watmath!utai}!lsuc!ncrcan!brian | | NCR Canada Ltd. | INTERNET: brian@ncrcan.Toronto.NCR.COM | +-------------------+--------------------------------------------------------+
honey@umix.cc.umich.edu (Peter Honeyman) (10/17/87)
pathalias is based on a directed graph model. so your figure should look like this: (500) A<----->B ^ ^ (200) | |(200) | | | v D<----->C (5000) with that understood, the route from A to D speaks for itself. peter