Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!think!harvard!cmcl2!acf4!mascagni
From: mascagni@acf4.UUCP (Michael Mascagni)
Newsgroups: net.news
Subject: Re: The USENET Backbone (Last changed: 28 February 1986)
Message-ID: <4820001@acf4.UUCP>
Date: Sat, 1-Mar-86 09:16:00 EST
Article-I.D.: acf4.4820001
Posted: Sat Mar  1 09:16:00 1986
Date-Received: Sun, 2-Mar-86 19:31:43 EST
References: <2869@gatech.CSNET>
Organization: New York University
Lines: 81

/* acf4:net.news / usenet@gatech.UUCP / 12:18 am  Mar  1, 1986 */
Original-from: Gene Spafford (gatech!spaf)
[Most recent change: 28 February 1986 by spaf]

A Usenet "backbone" site is one which exchanges every (non-local) news
article it receives with at least two other backbone sites; or which is
the main newsfeed for a particular area (e.g., Australia) and exchanges
news with at least one other backbone site.  This exchange is done
(theoretically) with minimum delay.  Thus, any article submitted to a
backbone site is supposed to propagate to all other backbone sites
within a very short time period. (Under actual conditions, your milage
may vary.)

Each backbone site normally feeds some number of well-connected
secondary sites, most of which are not "leaf" (terminal) nodes.
These secondary sites feed the news out to other distribution and leaf
nodes, and so on.

For optimal news distribution, each site should establish an "L" type
link with a site closely connected to a backbone site. This will help
ensure that any articles submitted from that site get propagated to the
whole net with a minimum of delay.  Sites should *not* request a news
feed from a backbone site unless they are willing to feed at least five
or six (or more) other, non-terminal sites.

Note that some backbone links (viz., seismo--munnari, utzoo--ALL,
hao--ALL, uw-beaver--ubc-vision, seismo--mcvax, seismo--gatech) do not
carry all newsgroups, including some "net" and "mod" newsgroups.  The
European component of Usenet receives a limited number of "net" and
"mod" groups, as well as having a number of active "eunet" newsgroups,
and exchanges all those articles via X.25 links.

To send mail to the administrators of all the backbone sites, address
your mail to "backbone@cbosgd.UUCP".  If you wish to send mail to the
administrator of a particular site, consult the uucp map for the name
and address of the appropriate individual(s).

Here is the backbone as of 1 March 1986:


	       mgnetp
		 |
         ------ihnp4-----------------------cbosgd
         |       |                           |
         |     alberta                       |
         |       |                           |
         |    ubc-vision      burl---------clyde----watmath----utzoo
         |       |             |                                 |
         |       |             |                                 |
         |       |          ulysses-------bellcore-----------\  linus
         |       |                                            \  |
         |       |                                             \ |
         |    uw-beaver----tektronix---------------------------decvax------
         |                     |                                 |        |
    |--qantel----------------\ | /--------oliveb----glacier----decwrl     |
    |                         \|/                                         |
    |  kddlab----------------hplabs-------sdcrdcf                         |
    |    |                     |             |                            |
    |    | (see below)        hao         sdcsvax                         |
    |    |/                    |                                          |
    |  mcvax-----------------seismo--------cmcl2-----------philabs-------mcnc
    |                         /|\                                         |
    ---------lll-crg---------/ | \---------gatech-----------------------akgua
                               |             |
                             munnari      drillsys


This is the European backbone (mcvax feeds all of them):

           penet  enea   diku   unido           penet -> Finland
             |      \     |     /		enea -> Sweden
             |       \    |    /		diku -> Denmark
             |        \   |   /			unido -> W. Germany
             |         \  |  /			vmucnam -> France
    vmucnam--+----------mcvax------cernvax	mcvax -> Netherlands
             |         /  |  \			cernvax -> Switzerland
             |        /   |   \			ukc -> Great Britain
             |       /    |    \		prlb2 -> Belgium
             |      /     |     \		i2unix -> Italy
	   vmars  ukc    prlb2   i2unix         vmars -> Austria
/* ---------- */