[NNTP] Article references

[Ruud H.G. van Tol]

Russ Allbery:
> Clive D W Feather:

>>    News reading clients have available a variety of mechanisms to
>>    retrieve articles via NNTP.  The news articles are stored and
indexed
>>    using three types of keys.  One key is the message-id of an
article.
>>    Another key is composed of the newsgroup name and the article
number
>>    within that newsgroup.  That key MUST be unique to a particular
>>    server (there will be only one article with that number within a
>>    particular newsgroup), but is not required to be globally unique.
>>    Additionally, because the same article can be cross-posted to
>>    multiple newsgroups, there may be multiple keys that point to the
>> -  same article on the same server.  The final key is the arrival
>> +  same article on the same server; nevertheless, a given article
>> +  MUST NOT have two different article numbers in any particular
>> +  newsgroup on a particular server. The final key is the arrival
>>    timestamp, giving the time that the article arrived at the server.

> I'm also fine with this.

I still see some problems. The "but is not required to be globally
unique" is trying to counter a popular misconception, but is not
adding much information.

First try:

News reading clients have available a variety of mechanisms to
retrieve articles via NNTP.  The news articles are stored and indexed
using three types of keys.

The first key is the message-id of an article.

The second type of key is composed of a newsgroup name and a rotation
number within that newsgroup.  That key is unique to a particular
server. An article has (gets? is assigned?) exactly one such unique key
per
served newsgroup that it is posted in. (that it belongs to?)
These article numbers are local to the newsgroup and to the server, so
the article is likely to have different article numbers in the related
newsgroups, and in the same newsgroup on different servers.

The third key is the arrival timestamp, giving the time that the article
arrived at the server. This key can be shared by multiple articles.



-- 
Grtz, Ruud