Re: [Dime] Adam Roach's No Objection on draft-ietf-dime-rfc4006bis-08: (with COMMENT)

[Yuval Lifshitz <[e-mail]>]

 Hi Adam, thanks for the review. Comments inline
    On Tuesday, May 22, 2018, 1:41:50 a.m. GMT+3, Adam Roach <[e-mail]> wrote:  
 
 Adam Roach has entered the following ballot position for
draft-ietf-dime-rfc4006bis-08: No Objection

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COMMENT:
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Thanks to the authors and other participants who helped with this revision of
the credit-control application. Thanks in particular for the addition of an
extensive privacy considerations section.

I will note that I only reviewed the diffs between this document and RFC 4006.

I have a handful of comments.

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General nit:

This document uses the term "service specific" as a compound adjective in
several places. As a compound adjective, this should be hyphenated (i.e.,
"service-specific").

[yuval] will fix

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§1.1:

This document uses lowercase forms of RFC-2119-defined terms. Please update this
section to use the boilerplate from RFC 8174.

[yuval] we use them in lowercase, without their normative meaning. Is this an issue?
For example: "a commercial agreement must exist between the visited domain and the home domain" is just informational

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§5.1.2:

>  If independent credit-control of multiple services is used, the
>  Validity-Time AVP and Final-Unit-Indication AVP or QoS-Final-Unit-
>  Indication AVP SHOULD be present either in the Multiple-Services-
>  Credit-Control AVP(s) or at command level as single AVPs.

The phrasing here is ambiguous -- it's not clear whether the requirement is:

  (Validity-Time and Final-Unit-Indication) or QoS-Final-Unit-Indication

... or ...

  Validity-Time and (Final-Unit-Indication or QoS-Final-Unit-Indication)

I suspect it's the latter, in which case I suggest:

  If independent credit-control of multiple services is used, the
  Validity-Time AVP, and either the Final-Unit-Indication AVP or
  the QoS-Final-Unit-Indication AVP, SHOULD be present either in the
  Multiple-Services- Credit-Control AVP(s) or at command level as single
  AVPs.

[yuval] yes. will fix

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§5.2.1:

The alignment of the "Diameter AAA Server" title on Figure 3 has changed from
RFC 4006 in a way that looks worse.

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[yuval] will fix

§5.6.2:

>  The credit-control
>  client receives a Credit-Control-Answer or service specific
>  authorization answer with the Final-Unit-Indication or the QoS-Final-
>  Unit-Indication AVP and Validity-Time AVPs but no Granted-Service-
>  Unit AVP.

This has the same confusion as above regarding the application of logical
combinations. The second half of the statement is of the form "A or B and C
but not D," which is pretty ambiguous. It's also a little unclear whether the
client receives a Credit-Control-Answer (with A or B and C but not D), or just
a Credit-Control-Answer of any description, full stop.

[yuval] how about this:
"When the credit-control client receives (either at session or service specific level) a Final-Unit-Indication AVP or QoS-Final-Unit-Indication AVP, together with Validity-Time AVP,but without Granted-Service-Unit AVP, it immediately starts the graceful service termination   without sending any message to the server."
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§8.19

>  Note: The values reported in a Used-Service-Unit AVP does not
>  necessarily have a relation to the grant provided in a Granted-
>  Service-Unit AVP, e.g., the value in this AVP may exceed the value in
>  the grant.

Nit: "...values reported in a Used-Service-Unit AVP do not..."
                                                    ^^

(or "...value... does not...")

[yuval] will fix

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§8.54:

>  The User-Equipment-Info-MAC (AVP Code TBD3) is of type OctetString.
>  The User-Equipment-Info-MAC AVP contains the 48-bit MAC address is
>  formatted as described in [RFC3580].

Nit: remove "is" after "address".

[yuval] will fix

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§8.65:

>  The Redirect-Address-IPAddress AVP (AVP Code TBD14) is of type
>  Address and defines the IPv4 or IPv6 address of the redirect server
>  with which the end user is to be connected when the account cannot
>  cover the service cost.

This appears to be underspecified, unless I've missed some specification
elsewhere regarding what the client is supposed to do with this IP address.
While the other redirection methods (HTTP, SIP) have relatively clear means of
contact (they indicate a protocol), the indication of only an IP address with
neither protocol nor port doesn't seem to provide enough information for a
client to act on.  Please either flesh this out in this section, or point to
another document that indicates how this IP address is to be used.

[yuval] I think this is left unspecifid on purpose. There are many ways to redirect IP addresses (e.g. different tunneling mechanism), don't think we want to list them here?[yuval]

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§12:

When new documents obsolete an RFC that originally registered values with IANA,
I'm used to seeing that document also update the IANA registry so that the
corresponding entries now point to the new document. You may consider text that
instructs IANA to update the existing RFC-4006-registered values so that they
point to this document instead of RFC 4006.

[yuval] don't know what the process here. but does it need to go into the RFC?

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Appendix B:

As a general comment for all of the examples: I'm surprised that none of the
examples have been updated to reflect the newly defined capabilities in this
document. For example, all the examples in this appendix use
Final-Unit-Indication rather than QoS-Final-Unit-Indication. In practice, to
show maximally flexible and compatible examples, I would expect that the
examples would include both AVPs. This applies to all of the "Extension"
AVPs as well.

[yuval] the examples are more around the flow and less about the actual content.
With respect to flow, there is no difference between the old and new AVPs - and we wanted to minimize unnecessary changes. Only flow that was modified was reflected in a new diagram at the end of section 5.6 ("zero GSU")
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Appendix B.2:

>  control server.  Therefore, in this example, it is assumed that the
>  SIP Proxy adds a Record-Route header in the initial SIP INVITE

"...a Record-Route header field..."

(A SIP header is everything before the first blank line; individual lines within
a SIP header are called "header fields")

[yuval] ok. will fix

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