Re: [yam] Issue #7: RFC 5321 Section 2.2.2: add a bullet for the definition of extensions

[Alessandro Vesely <[e-mail]>]

SM wrote:
>> 5321 and 4409 are both on the yam list. Which one(s) of them define 
>> extensions?
>
> The Extension Model is defined in Section 2.2 of RFC 5321.

Yes it is, but no IANA registry of extensions is defined. RFC 4409 
defines no registry either, but lists its initial values. Will that 
list have to be updated for 4409bis? And how will it be maintained 
thereafter?

>> They'll have to agree with each other...
>
> Yes but it is better not to have each document reference each other 
> normatively.

This can be avoided with a well crafted IANA registry definition: 
RFC 5321 may just acknowledge that the extension mechanism can be 
reused by "other protocols", if they are similar enough to SMTP. The 
extensions IANA table definition may thus provide for adding a 
column for each look-alike protocol, and a row for each extension. 
The RFCs where the look-alike protocol is defined must also provide 
the column values for already registered extensions --which is what 
4409bis would then do. Likewise, as new extensions register 
additional rows, they must provide the values for already existing 
columns.

That way, 2033bis would be able to add its own column as well, 
without circular normative references.