transport for Internet sites
Rich Salz, Open Software Foundation
|NNTP, the Network News Transfer Protocol, has been labelled the most widely
implemented elective protocol in the Internet. The growth of the Internet has meant more
sites exchanging NNTP data. While the explosive growth in Usenet traffic places demands
on all sites, the goal of fast network access puts particular demands on NNTP hosts.
InterNetNews is an implementation of the Usenet transport layer designed to address
IntroductionUsenet is a distributed bulletin board system,
built as a logical network on top of other networks
and connections. By design, messages resemble
standard Internet electronic mail messages as defined
in RFC822 [Crocker82]. The Usenet message for-
mat is described in RFC1036 [Adams87]. This
defines some additional headers. It also limits the
values of some of the standard headers as well as
giving some of them special semantics.
Newsgroups are the classification system of
Messages generated at a site are sent to the
Figure 1 : Small Usenet topology (all links are two -way).
The Path header is used to prevent message|
loops. For example, an article written at A could get
sent to B , D , C , and then back to A. Before pro-
pagating an article, a site prepends its own name to
the Path header. Before propagating an article to a
site, the receiving host checks to make sure that the
site that would receive the article does not appear in
the Path line. For example, when the article arrived
at site C , the Path would contain A!B!D , so site C
would know not to send the article to A.
Sites also keep a record of the Message -ID's of
For the past few years, the amount of data gen-
The number of sites participating in Usenet has
1 Yes, this means that, as far as the software is
concerned, Usenet is over 90% noise.