On 12/1/11 10:08 PM, Dan York wrote:
Paul,
Many thanks as always for your helpful comments. The question seems to
be that we want to define ABNF that describes an example like this:
P-Charge-Info: <sip:6835555555;npi=001;noa=3@10.10.7.21>
I have lost track, but I think there were prior proposals to incorporate
the above parameters into the syntax of the tel URI. But AFAICT that was
never done. (There were issues with it, raised by me among others.) (If
they were valid in tel, then they would be valid in sip URIs too, since
the sip uri can contain telephone-subscriber from the tel uri.)
IIUC, here you are trying to introduce these parameters into the user
part of a sip uri, when used in P-Charge-Info, without extending them
for other uses of the sip uri or tel uri. Is that right?
The optional npi and noa parameters are parameters that are on the left
side of the @ symbol in a SIP URI.
In looking at the original ABNF we had in there, it does seem to me that
it *was* incorrect, as it would have required a URI of something like
one of these:
P-Charge-Info: <sip:6835555555@10.10.7.21;npi=001;noa=3>
P-Charge-Info: <sip:6835555555@10.10.7.21>;npi=001;noa=3
Yes, that is what it would have required. Whether that is correct or
incorrect is an open question. But I guess it is contrary to your intent.
I'm guessing the former... but it's irrelevant - the point is that
either of these would be wrong. We need the ABNF to specify that THIS is
the correct notation:
P-Charge-Info: <sip:6835555555;npi=001;noa=3@10.10.7.21>
So we really do want to specify somehow that "chargeparam" is part of
the "userinfo" section of the SIP URI, and perhaps specifically the
"user" section given these definitions:
RFC 3261:
userinfo = ( user / telephone-subscriber ) [ ":" password ] "@"
user = 1*( unreserved / escaped / user-unreserved )
RFC 2806:
telephone-subscriber = global-phone-number / local-phone-number
Any ABNF experts out there able to help me sort this out? The current
formal definition is:
Technically the parameters you want are already *syntactically* valid,
in two different ways:
They fit the definition of 'parameter' in tel (RFC 3966),
they are consistent within the definition of 'user' in 3261.
So in some sense you don't need to extend the syntax definitions at all.
But that doesn't say anything about semantics. So at least you would
need to define the semantics of these.
BUT...
There is now a registry of parameters for the TEL URI, defined by RFC
5341. If you *don't* register these parameters there, then you run the
risk that they might subsequently be registered by somebody else as tel
uri parameter, with some different meaning.
So, I think you cheat if you don't define these as new tel uri
parameters. But if you define them as tel uri parameters, then
presumably they can be used anywhere a tel or sip uri can be used.
Perhaps they could somehow be defined somehow to limit their use to
certain contexts, but I don't know how you would go about that.
If these parameters are only to be meaningful in p-charge-info, then the
right thing to do is define them as header field parameters, as you did
have them once, even though they are then positioned differently than
you were hoping for.
Thanks,
Paul
----
The syntax of the P-Charge-Info header is described as follows:
P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec)
; name-addr and addr-spec are specified in RFC 3261
charge-param = npi-param / noa-param / generic-param
npi-param = ";npi" EQUAL npi-value
; generic-param is specifed in RFC 3261
npi-value = 3DIGIT
noa-param = ";noa" EQUAL noa-value
noa-value = gen-value
The SIP URI is the billing indicator that is passed between the
parties.
charge-param is used as a userinfo parameter in P-Charge-Info.
----
Thanks,
Dan
On Nov 29, 2011, at 8:59 PM, Paul Kyzivat wrote:
On 11/30/11 3:38 AM, Dan York wrote:
Brett, (and replying from a slightly different address so that it will
go to the SIPPING list)
Thank you for the feedback and question. The ABNF in the draft has
evolved over the past almost-4 years as various people more literate
than I in ABNF have given us feedback and we've updated the draft.
In the ABNF section, "chargeparam" is intended to represent that you
could optionally have the "noa", "npi" parameters - or any other generic
parameters found in RFC 3261(such as "user=phone")
Including generic-param is a mechanism for making the syntax
compatible with future enhancements. But allowing it syntactically
doesn't specify how parameters that match generic-param are to be
processed if the are present on this header. Typically you would
specify in the draft that they should be ignored unless the behavior
is defined by some other specification.
Originally, the ABNF read:
P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec)*
(SEMI charge-param)
; name-addr and addr-spec are specified inRFC 3261
<http://tools.ietf.org/html/rfc3261>
charge-param = npi-param / noa-param / generic-param
I thought that was fairly clear and made sense. However, I changed the
ABNF in rev -10 in October 2010 to more simply:
P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec)
; name-addr and addr-spec are specified inRFC 3261
<http://tools.ietf.org/html/rfc3261>
charge-param = npi-param / noa-param / generic-param
after someone strongly made the case that the "* (SEMI charge-param)"
was not required because it was a "userinfo parameter" to the
name-addr/addr-spec element.
That is something very different. What you have above are *header*
parameters for the P-Charge-Info header.
It sounds like you are talking about TEL-URI parameters when the tel
uri has been converted to a sip URI. But if so, then you should be
defining an extension to the tel-uri syntax. And then you would need
to define the semantics relative to the tel-uri. (It isn't really
kosher to define the parameters on the tel-uri but then only define
their semantics relative to the P-Charge-Info header.)
IMO its wrong to make this change. Rather you should go back to
defining these explicitly as header params for P-Charge-Info.
Thanks,
Paul
Unfortunately, the email exchange about
this seems to have NOT taken place on the mailing list but rather in a
private email exchange - and I no longer have access to the archives of
the email account where that occurred (I am no longer with Voxeo) - so I
don't know who it was that argued for this change.
I'm directly cc'ing John Haluska as he was involved in with a number of
those exchanges and can perhaps clarify this.
In reviewing section 19.1.1 of RFC 3261 (
http://tools.ietf.org/html/rfc3261#section-19.1.1 ) and sections 19.1.2,
19.1.3, and 19.1.6 as well as the ABNF in section 25, I am guessing that
the rationale was because the "charge-param" does fit into the "user"
section of the URI.
So that's a roundabout way of saying that it is part of "user", as I
interpret the ABNF in RFC 3261.
Do you have suggestions for how to make this clearer in the draft? Would
the original ABNF be more useful to you? Should the sentence
"charge-param is used as a userinfo parameter in P-Charge-Info" indicate
that it is the "user" part of the "userinfo" field?
Thanks,
Dan
P.S. After not receiving any feedback for many, many months I suddenly
have received two email questions/comments about P-Charge-Info today. I
don't know if this is as a result of the mention on a mailing list that
Richard Shockey mentioned... but I was surprised.
On Nov 29, 2011, at 1:35 PM, Brett Tate wrote:
Howdy,
Draft-york-sipping-p-charge-info-12 includes the following ABNF
without explicitly indicating if the charge-param is part of user,
telephone-subscriber, or both. I'm not sure how to interpret the
charge-param statement since userinfo has no parameters (although user
and telephone-subscriber can have them).
Is charge-param part of user, telephone-subscriber, or both? I
recommend updating section 7 to remove the ambiguity.
Thanks,
Brett
------
Draft-york-sipping-p-charge-info-12:
"The syntax of the P-Charge-Info header is described as follows:
P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec)
; name-addr and addr-spec are specified in RFC 3261
charge-param = npi-param / noa-param / generic-param
npi-param = ";npi" EQUAL npi-value
; generic-param is specifed in RFC 3261
npi-value = gen-value
noa-param = ";noa" EQUAL noa-value
noa-value = gen-value
The SIP URI contained in the name-addr/addr-spec is the billing
indicator that is passed between the parties.
charge-param is used as a userinfo parameter in P-Charge-Info."
RFC 3261:
userinfo = ( user / telephone-subscriber ) [ ":" password ] "@"
user = 1*( unreserved / escaped / user-unreserved )
RFC 2806:
telephone-subscriber = global-phone-number / local-phone-number
--
Dan York dyork@xxxxxxxxxxxxx <mailto:dyork@xxxxxxxxxxxxx>
<mailto:dyork@xxxxxxxxxxxxx>
Phone: +1-802-735-1624 skype:danyork
http://www.danyork.com/
http://twitter.com/danyork
--
Dan York dyork@xxxxxxxxxxxxx <mailto:dyork@xxxxxxxxxxxxx>
<mailto:dyork@xxxxxxxxxxxxx>
http://www.danyork.com/ skype:danyork
Phone: +1-802-735-1624
Twitter - http://twitter.com/danyork
--------------------------------------------------------
All comments and opinions are entirely my own and have no connection
whatsoever to any employer, past or present. Indeed, by tomorrow even I
might be disavowing these comments.
--------------------------------------------------------
_______________________________________________
Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@xxxxxxxxxxxxxxx
<mailto:sip-implementors@xxxxxxxxxxxxxxx> for questions on current sip
Use sip@xxxxxxxx <mailto:sip@xxxxxxxx> for new developments of core SIP
_______________________________________________
Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@xxxxxxxxxxxxxxx
<mailto:sip-implementors@xxxxxxxxxxxxxxx> for questions on current sip
Use sip@xxxxxxxx <mailto:sip@xxxxxxxx> for new developments of core SIP
--
Dan York dyork@xxxxxxxxxxxxx <mailto:dyork@xxxxxxxxxxxxx>
http://www.danyork.com/ skype:danyork
Phone: +1-802-735-1624
Twitter - http://twitter.com/danyork
--------------------------------------------------------
All comments and opinions are entirely my own and have no connection
whatsoever to any employer, past or present. Indeed, by tomorrow even I
might be disavowing these comments.
--------------------------------------------------------
_______________________________________________
Sipping mailing list https://www.ietf.org/mailman/listinfo/sipping
This list is for NEW development of the application of SIP
Use sip-implementors@xxxxxxxxxxxxxxx for questions on current sip
Use sip@xxxxxxxx for new developments of core SIP
