On 10/19/18 7:08 AM, Warren Kumari wrote:
So, there were a few documents where I was not able to quickly figure
out which of the classes it should be placed in.
tl;dr: my analysis is that all four of the mentioned documents should be
removed from the list. Details below.
RFC3861 describes how to use SRV, but it is updated by RFC6121, which
largely says "Don't!" -- what do we do here? Update both? Just
RFC3861? Juast RFC6121?
That's sort of true. 3861 defines rules for _im._x and _pres._x (for
arbitrary values of "x"), while 6121 says "don't do this for x = xmpp."
For example, RFC 5509 builds on RFC 3861 for SIP, and it's technically
still in effect (although the practical case is probably the same as
XMPP, no one has produced a revision to 5509 that says as much).
All of that notwithstanding, 3861 most definitely does not deal with
"Global" underscored node names as -attrleaf- defines that term. It
deals only with labels further down the tree. I believe it should be
removed from the list.
I couldn't figure out RFC3404, and RFC6011.
Clue appreciated.
RFC3404 -- Dynamic Delegation Discovery System (DDDS) Part Four: The
Uniform Resource Identifiers (URI) Resolution Application
Perhaps SRV? But it doesn't really seem to be underscore scoped...
This one is quite perplexing, and I don't know how it got caught up in
Dave's net. The character "_" appears only 12 times in this document,
all in variable names in the pseudo-code in its appendix. Neither of the
English words "underscore" nor "underline" appear at all.
As far as I recall (and a quick skim seems to validate this), the only
reservations DDDS makes are under "urn.arpa." and "uri.arpa." -- there
aren't any global name reservations, with or without underscores.
I think this document was included in error.
RFC6121 -- Extensible Messaging and Presence Protocol (XMPP): Instant
Messaging and Presence
This updates RFC3921 and explicitly recommends against SRV.
"Interoperability Note: RFC 3921 specified how to use the _im._xmpp
and _pres._xmpp SRV records [IMP-SRV] as a fallback method for
discovering whether a remote instant messaging and presence service
communicates via XMPP. Because those SRV records have not been widely
deployed, this document no longer specifies their use, and new
implementations are not encouraged."
Should this be in this list?
RFC 6121, as you point out, only mentions _{im,pres}.xmpp as an
historical note while deprecating its use. I believe it should also be
removed.
RFC3861 -- Extensible Messaging and Presence Protocol (XMPP): Instant
Messaging and Presence
See above. It would be SRV, but was updated by RFC6121.
[see above]
RFC6011 -- Session Initiation Protocol (SIP) User Agent Configuration
I got confused here -- I cannot really see the underscore names here
as anything other than a target name.
6011 shouldn't be updated by this document. The only underscored node
names in that document are in non-normative examples, and they're
actually incidental to the purpose of the example. Presumably, they're
included to demonstrate that querying for NAPTR records can return both
UA Config records *and* other, unrelated records, and that
implementations need to ignore the unrelated records.
Thanks for doing the heavy lifting on this. I think it has dramatically
improved the document to figure out why each updated RFC is included,
since it flushed out several that should not be.
/a
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