Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/17/84 chuqui version 1.7 9/23/84; site nsc.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!nsc!chuqui From: chuqui@nsc.UUCP (Chuq Von Rospach) Newsgroups: net.news Subject: Re: a harmless query... Message-ID: <2665@nsc.UUCP> Date: Sat, 4-May-85 13:33:12 EDT Article-I.D.: nsc.2665 Posted: Sat May 4 13:33:12 1985 Date-Received: Sun, 5-May-85 23:37:00 EDT References: <185@greipa.UUCP> Reply-To: chuqui@nsc.UUCP (Chuq Von Rospach) Distribution: net Organization: The Courts of Chaos Lines: 35 Summary: In article <185@greipa.UUCP> paul@greipa.UUCP (Paul A. Vixie) writes: >My understanding of news is that every system sends every article it >receives to every machine it feeds. Lots of "every"'s in that... Not quite true. Any site that is already in the 'Path' header line will not see the message again because inews will recognize that as a duplication and not ship it. Also, 'every' system doesn't send 'every' article to 'every' machine it feeds (these definitions may vary, void where prohibited by law). For example, for 'net.all' nsc gets almost all of its news from a single site, hplabs. We ship this data to three sites, cadtec, daisy, and voder. In our case we almost never see a duplicate message because we only get a single feed. Sites downstream of us also don't see duplicates because they only get their news from us. When you have multiple sites feeding in, you will get duplicates. Hplabs is an example of this, because they get news from (I believe) hao, tektronix, and sdcrdcf. Major sites such as this are the exception instead of the rule, though, and the duplication tends to be acceptable because it allows the news distribution to be sped up by cutting down on the paths it has to travel. It'd be nice to be able to recognize duplicates before shipping them, but the first try at that (inews has an IHAVE/SENDME protocol that attempts to deal with this...) doesn't work because of the turnaround delays in uucp lines. What happens is that in many cases between the time you ship out the SENDME and the time you get the messages someone else shipped them as well and the duplicates show up anyway. You end up slowing news down significantly (three phone calls instead of one for a set of messages) adding a lot of volume to your uucp link (three sets of messages -- an IHAVE, a SENDME, and the message itself) and it didn't really help. -- :From the offices of Pagans for Cthulhu: Chuq Von Rospach {cbosgd,fortune,hplabs,ihnp4,seismo}!nsc!chuqui nsc!chuqui@decwrl.ARPA Who shall forgive the unrepentant?