Subject: Re: [Ecrit] draft-ietf-ecrit-additional-data-10: mandatory elements in blocks

From: Hannes Tschofenig <[email-masked]>
Date: Wed, 16 Oct 2013 11:52:32 +0200

Hi Barbara,

On 07/31/2013 07:09 PM, STARK, BARBARA H wrote:
> Comments related to blocks with no mandatory elements. The Use
> statements for an element should not be considered a statement as to
> whether the block itself is mandatory or optional. Bock
> usage/inclusion Use statements need to be elsewhere. So Use of an
> element is restricted to use of that element within a block that
> exists. ------------- 3.3.  Device Information
>
> Comment 20: It's sort of weird that there's not a single required
> element for this block. But, ok.

We found it hard to declare some of the data elements mandatory given 
the wide range of scenarios where additional data is used.

> Does this mean it's possible to have
> the block present with nothing in it?

Theoretically, this is possible. Of course, it wouldn't be useful as such.

  -------------- 3.4.1.  xCard
> for Subscriber's Data Use:  Conditional : Some services (e.g.,
> prepaid phones, initialized phones, etc.) may not have this
> information.
>
> Comment 21: What's the condition? Or is it really just Optional? As
> with DeviceInfo block, there are no required elements.

We changed the wording:

-----

3.4.2.  xCard for Subscriber's Data

    Data Element:  xCARD for Subscriber's Data

    Use:  Conditional.  Subscriber data is provided unless it is not
       available.  Some services, for example prepaid phones, non-
       initialized phones, etc., do not have information about the
       subscriber.

    XML Element:  <SubscriberData>

    Description:  Information known by the service provider or device
       about the subscriber; e.g., Name, Address, Individual Telephone
       Number, Main Telephone Number and any other data.  N, ORG (if
       appropriate), ADR, TEL, EMAIL are suggested at a minimum.  If more
       than one TEL property is provided, a parameter from the vCard
       Property Value registry MUST be specified on each TEL.

    Reason for Need:  When the caller is unable to provide information,
       this data may be used to obtain it

    How Used by Call Taker:  Obtaining critical information about the
       caller and possibly the location when it is not able to be
       obtained otherwise.

-----

  But in this
> case, this is the only possible element. So it seems that if a
> Subscriber block exists, then this SubscriberData element is
> Required. Otherwise it makes no sense for the Subscriber block to
> exist.

At the moment this is the only possible element but the structure is 
extensible and so there could be something else in the future.

  -------------- 3.5.1.  Comment
>
> Data Element:  EmergencyCall.Comment
>
> Use:  Optional
>
> Comment 22: Again, it makes no sense for the one possible element of
> a block to be optional when that block is present. This is a
> statement about the existence of this element in the block and not
> about the block itself. All blocks are effectively optional.

It is true that it is not useful to send an empty block and we could say 
that but of course that does not prvent anyone from still sending it. 
So, there is no harm in sending an empty block since it will just be 
parsed and nothing happens.

Ciao
Hannes

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