Gen-ART review of draft-ietf-bliss-shared-appearances-12

[<[e-mail]>]

The -12 version of this draft resolves all of the comments in the
Gen-ART review of the -11 version.

Thanks,
--David

> -----Original Message-----
> From: Black, David
> Sent: Thursday, June 28, 2012 4:51 PM
> To: [e-mail]; [e-mail];
> [e-mail]; [e-mail]
> Cc: Black, David; Shida Schubert; [e-mail]; IETF Discussion; Robert
> Sparks
> Subject: Gen-ART review of draft-ietf-bliss-shared-appearances-11
> 
> I am the assigned Gen-ART reviewer for this draft. For background on
> Gen-ART, please see the FAQ at
> <http://wiki.tools.ietf.org/area/gen/trac/wiki/GenArtfaq>.
> 
> Please resolve these comments along with any other Last Call comments
> you may receive.
> 
> Document: draft-ietf-bliss-shared-appearances-11
> Reviewer: David L. Black
> Review Date: June 28, 2012
> IETF LC End Date: June 28, 2012
> IESG Telechat date: (if known)
> 
> Summary:
> 
> This draft is on the right track but has open issues, described in the review.
> 
> This draft describes support for shared appearances in support of multi-line
> and shared-line telephone often found in businesses.  All of the open issues
> are minor.  The draft is well-written and reasonably clear for the most part,
> although significant SIP expertise is required to completely understand it.
> 
> Major issues:  None.
> 
> Minor issues:
> 
> 4.1 - REQ-16:
> 
>    in this case, seizing the line is the same thing as dialing.
> 
> That seems wrong - I would have thought it was a "prerequisite" as
> opposed to "the same thing" because seizing the line is immediately
> followed by a dialing request.
> 
> 5.3.
> 
>    A user may select an appearance number but then abandon placing a
>    call (go back on hook).  In this case, the UA MUST free up the
>    appearance number by removing the event state with a PUBLISH as
>    described in [RFC3903].
> 
> What happens when that can't be done due to UA or network failure?
> 
> 5.4.
> 
>    A 400 response is returned if the chosen appearance number is invalid,
> 
> Is that always a 400 (Bad Request) or is any 4xx response allowed?  If
> it's always 400, add the words "Bad Request" after "400".
> 
>    If the Appearance Agent policy does not allow this, a 400 response
>    is returned.
> 
> Same question.  In addition, is 403 Forbidden allowed here?
> 
>    If an INVITE is sent by a member of the group to the shared AOR (i.e.
>    they call their own AOR), the Appearance Agent MUST assign two
>    appearance numbers.  The first appearance number will be the one
>    selected or assigned to the outgoing INVITE.  The second appearance
>    number will be another one assigned by the Appearance Agent for the
>    INVITE as it is forked back to the members of the group.
> 
> How does that interact with the single appearance UAs in 8.1.1 that won't
> understand the second appearance number?  A warning that such a UA can't
> pick up its call to its own AOR would suffice, either here or in 8.1.1.
> 
> 9.1
> 
>    A UA that has no knowledge of appearances must will only have
>    appearance numbers for outgoing calls if assigned by the Appearance
>    Agent.  If the non-shared appearance UA does not support Join or
>    Replaces, all dialogs could be marked "exclusive" to indicate that
>    these options are not available.
> 
> Should that "could be marked" be changed to "SHOULD be marked" ?
> Also, analogous questions for "could" in 9.2 and "can" in 9.3.
> 
> All three of these affect interoperability.
> 
> 12. Security Considerations
> 
> In general, this section is weak on rationale - the second, third and
> fourth paragraphs should all explain more about the purpose of and/or
> rationale for their security requirements (e.g., what does the security
> mechanism protect against and when/why might that protection be desired
> and/or required?).
> 
>    NOTIFY or PUBLISH message bodies that provide the dialog state
>    information and the dialog identifiers MAY be encrypted end-to-end
>    using the standard mechanisms.
> 
> What are "the standard mechanisms"?  List them, and provide references,
> please.
> 
> Please ensure that the section 6 XML and Section 7 ABNF are
> syntax-checked with actual tools.
> 
> Nits/editorial comments:
> 
> p.10:
> 
>    The next section discusses the operations used to implement parts of
>    the shared appearance feature.
> 
> "The following list describes the operations ..." would be better.
> 
> 5.3.1.
> 
>    A UA wanting to place a call but not have an appearance number
>    assigned publishes before sending the INVITE without an 'appearance'
>    element but with the 'shared' event package parameter present.
> 
> I think I understand what was intended here, but this would be clearer
> if "publishes" was replaced with language about sending a PUBLISH.
> It's also not completely clear whether "without" applies to the
> INVITE or the PUBLISH, so this sentence probably needs to be reworded.
> 
> 5.4. - Expand B2BUA acronym on first use.
> 
> idnits 2.12.13 ran clean.
> 
> Thanks,
> --David
> ----------------------------------------------------
> David L. Black, Distinguished Engineer
> EMC Corporation, 176 South St., Hopkinton, MA  01748
> [phone]             FAX: [phone]
> [e-mail]        Mobile: [phone]
> ----------------------------------------------------