Xref: utzoo news.misc:1054 news.config:366
Path: utzoo!mnetor!uunet!husc6!ukma!gatech!purdue!spaf
From: spaf@cs.purdue.EDU (Gene Spafford)
Newsgroups: news.misc,news.config
Subject: The USENET Backbone (Last changed: 10 December 1987)
Message-ID: <2802@arthur.cs.purdue.edu>
Date: 1 Jan 88 20:41:04 GMT
Expires: 10 Feb 88 20:41:03 GMT
Organization: Dept. of Computer Sciences, Purdue Univ.
Lines: 89
Supersedes: <127@uther.cs.purdue.edu>


Original-from: Gene Spafford (spaf@purdue.edu)
[Most recent change: 10 December 1987 by biep@cs.vu.nl]

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 mileage
may vary.)  Backbone sites are also expected to be running a recent
version of the news software, provide a stable news and mail relay
service, and be maintained by reasonably adept and responsible staff.

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., ALL--munnari, mnetor--uunet,
uw-beaver--ubc-vision, uunet--mcvax) do not carry all newsgroups,
usually meaning "talk" and some "rec" groups, but sometimes also
including "soc", "sci", "news", "misc", and "comp" newsgroups.  The
European component of Usenet receives a limited number of groups from
outside Europe, 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@rutgers.edu".  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).  (In Europe uucp map
entries are obtained through the national backbone's "netdir"
service).



Here is the backbone as of 1 January 1988 (dotted lines show 
restricted links):

         /-----------------------------------------------------\
        /                                                       \
bellcore-----ulysses      alberta-----ucb-vision                 \ (linus)
 |    |                     |              :                      \   |
 |  clyde-----cbosgd-----ihnp4         uw-beaver-----tektronix-----decvax-\
 | /   |                                     :           |          |  |   \
 | | watmath-----utgpu  vuwcomp	(europe)  (mit-eddie)  cae780       |  |   |
 | |               |        :       |                    |          |  |   |
 | | (ames)      utzoo   munnari  mcvax ... kddlab ... hplabs---decwrl |   |
 | |   /           |         :   /                       :             |   |
 | |  /          mnetor ... uunet----------------------amdahl          |   |
 | | /                           \                       |             |   |
 | | |  /---cmcl2-----philabs     \---------nbires       |             /   |
 | | | /      |         |                      :         |            /    |
rutgers-----husc6-----linus-----(decvax)       :         |   /----ucbvax   |
  | |  \      |  \                             :         |  /       |      |
  | |   \     |   \---------------------------hao-------ames-----sdcsvax   |
  | |    \    |                                |         |                 |
  \ \     mit-eddie ... (uw-beaver)            |     (rutgers)             |
   \ \                                         |                           |
    \ \--------------------------------------gatech----------------------mcnc
     \                                                                   /
      \-----------------------------------------------------------------/

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

            tut   enea   diku   unido   hafro   	tut -> Finland
             |      \     |     /	  |		enea -> Sweden
             |       \    |    /	  |		diku -> Denmark
             |        \   |   /		  |		unido -> W. Germany
             |         \  |  /		  |		inria -> France
    inria----+----------mcvax-------------+       	mcvax -> Netherlands
             |         /  |  \	          |		cernvax -> Switzerland
             |        /   |   \	          |		ukc -> Great Britain
             |       /    |    \          |		prlb2 -> Belgium
             |      /     |     \         |		i2unix -> Italy
	   tuvie  ukc    prlb2   i2unix  cernvax	tuvie -> Austria
							hafro -> Iceland

-- 
Gene Spafford
Dept. of Computer Sciences, Purdue University, W. Lafayette IN 47907-2004
Internet:  spaf@cs.purdue.edu	uucp:	...!{decwrl,gatech,ucbvax}!purdue!spaf