The new streaming mode already allows a better way for news exchange between news servers. This mode is explained in [Bar97]. However, news is still lacking a way to compress articles before they are transferred on the network. This is especially necessary and useful for networks connected over limited bandwidth links.
To eliminate this problem, we suggest the implementation of a new transfer mode to allow the compressed transmissions of articles. However, this is only a proposal for the discussion of the commands explained here and no bullet proof extension.
The compression extension is activated using the mode
compressed and deactivated using the mode uncompressed
commands. Other commands should be defined for the negotiation of the
compression algorithm. However, since the compression of the articles
may imply a higher processor load on the news server the news server
is allowed to neglect this extensions for some or all hosts. We expect
that the transmission of news in a compressed format can reduce the
required network bandwidth by over 
.
Articles containing readable text only can usually be compressed by
over 
. Binary or compressed articles (e.g., program files) are
encoded to a subset of the ASCII character set before they are
transmitted by NNTP, because NNTP only guarantees to transfer a subset
of the ASCII character set correctly. Hence those compressed and
uuencoded or base64 encoded can still be reduced by .
As soon as the compression is turned on, the news server may decide before transmitting an article whether the article is transmitted compressed or uncompressed. This decision may be based on the article's size and compressibility. Whenever the news server transfers an article in compressed format it indicates this using the reply code (see appendix B for an explanation of NNTP). For example, this may be done by using a different numeric reply or by appending a ``c'' for compressed to the numeric reply code.