Subject: [dispatch] Two new VoIP spam drafts

From: Henning Schulzrinne <[email-masked]>
Date: Sat, 1 Oct 2016 01:03:28 +0000

In collaboration with members of the Robocall Strike Force (https://www.fcc.gov/news-events/events/2016/08/first-meeting-industry-led-robocall-strike-force), I have submitted two I-D's:

https://datatracker.ietf.org/doc/draft-schulzrinne-dispatch-status-unwanted/

https://datatracker.ietf.org/doc/draft-schulzrinne-dispatch-callinfo-spam/

that fill in operational needs for dealing with SIP spam. The first defines a new status code (666) that users can use to mark unwanted calls, either as a response code to an INVITE or in a Reason header in a BYE response. (This will likely be supplemented in practice by API-based mechanisms for post-call spam reports.)

The second defines a set of Call-Info parameters that allow the carrier or other UE-trusted SIP entity in the path to indicate the spam probability, type of call and other related information that will allow the UE and user to make better call handling decisions.

This complements the 'verstat' work being submitted to 3GPP (by others), for indicating the level of trust in the From/PAI tel URI.

Both are obviously pretty drafty, so comments on the approach are particularly appreciated.

Henning

---

From: Paul Kyzivat <[email-masked]>
Date: Fri, 30 Sep 2016 22:36:57 -0400

Audacious move choosing 666!

I want to verify that it is crystal clear that the meaning of this 
response is that requests (often calls) from this caller are unwanted, 
rather than simply that this *call* is unwanted.

At the time of call initiation there is of course little else that the 
callee has to go on to reject the call this way. But I guess I could 
imagine a UA that is intended only for originating calls, that considers 
*all* incoming calls to be undesirable, regardless of caller. In that 
case it would be bad to use 666 if that then put the caller on a list as 
an undesirable caller.

And of course this code can be used with Reason to signify displeasure 
with a call after it has been answered. At that point there may be a 
wider range of reasons to object to the call. E.g., the subject matter 
is objectionable, the caller is identifiable and objectionable even 
though coming from a usually unobjectionable number, etc.

It isn't necessary to boil the ocean here covering all the cases. I just 
want to make certain the all those using this code have a common 
understanding of the semantics.

	Thanks,
	Paul

On 9/30/16 9:03 PM, Henning Schulzrinne wrote:
> In collaboration with members of the Robocall Strike Force
> (https://www.fcc.gov/news-events/events/2016/08/first-meeting-industry-led-robocall-strike-force),
> I have submitted two I-D's:
>
>
> that fill in operational needs for dealing with SIP spam. The first
> defines a new status code (666) that users can use to mark unwanted
> calls, either as a response code to an INVITE or in a Reason header in a
> BYE response. (This will likely be supplemented in practice by API-based
> mechanisms for post-call spam reports.)
>
>
> The second defines a set of Call-Info parameters that allow the carrier
> or other UE-trusted SIP entity in the path to indicate the spam
> probability, type of call and other related information that will allow
> the UE and user to make better call handling decisions.
>
>
> This complements the 'verstat' work being submitted to 3GPP (by others),
> for indicating the level of trust in the From/PAI tel URI.
>
>
> _______________________________________________
> dispatch mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/dispatch
>

---

From: Henning Schulzrinne <[email-masked]>
Date: Sat, 1 Oct 2016 02:51:05 +0000

Yes, this is meant to indicate that the calls from that caller are unwanted. Given that numbers get re-assigned and that sometimes people hit the wrong button (such as hitting the "spam" button in gmail when I meant delete), this should presumably be treated more as a statistical indicator. I didn't want to be too prescriptive here; for example, it is possible that such calls, if they are not yet on a global blacklist, end up in the equivalent of the email spam folder, i.e., voicemail, or that, again mimicking email, you get a text message indicating calls that got this treatment, just in case this was a mistake.

I'll add a sentence about the caller being unwanted.

I had considered adding Call-Info "type" information to allow the called party to provide more information, but I doubt that most users will want to make in-depth selections of the nature of the badness when they just want to get rid of the call. More detailed feedback seems more appropriate for a post-call app-style response (and existing robocall filtering apps seem to allow this type of labeling).

Call-Info can't be used in a BYE, so that method doesn't quite work.

My inclination is to keep it simple for now, and consider adding more structured information as a parameter separately and later if there's need.

Henning
________________________________
From: dispatch <[email-masked]> on behalf of Paul Kyzivat <[email-masked]>
Sent: Friday, September 30, 2016 10:36 PM
To: [email-masked]
Subject: Re: [dispatch] draft-schulzrinne-dispatch-status-unwanted

        Thanks,
        Paul

---

From: Paul Kyzivat <[email-masked]>
Date: Fri, 30 Sep 2016 23:24:49 -0400

On 9/30/16 10:51 PM, Henning Schulzrinne wrote:
> Yes, this is meant to indicate that the calls from that caller are
> unwanted. Given that numbers get re-assigned and that sometimes people
> hit the wrong button (such as hitting the "spam" button in gmail when I
> meant delete), this should presumably be treated more as a statistical
> indicator. I didn't want to be too prescriptive here; for example, it is
> possible that such calls, if they are not yet on a global blacklist, end
> up in the equivalent of the email spam folder, i.e., voicemail, or that,
> again mimicking email, you get a text message indicating calls that got
> this treatment, just in case this was a mistake.
>
>
> I had considered adding Call-Info "type" information to allow the called
> party to provide more information, but I doubt that most users will want
> to make in-depth selections of the nature of the badness when they just
> want to get rid of the call. More detailed feedback seems more
> appropriate for a post-call app-style response (and existing robocall
> filtering apps seem to allow this type of labeling).
>
>
> My inclination is to keep it simple for now, and consider adding more
> structured information as a parameter separately and later if there's need.

I just want to ensure that all the users of this are on the same page 
regarding its meaning. How it is institutionalized is more important 
than what the exact wording is in this document. Users are going to push 
a button on their phone to reject the call. (Probably the same one that 
is there now.) What they mean and how that is used had better be in 
agreement.

	Thanks,
	Paul

> Henning
> ------------------------------------------------------------------------
> *From:* dispatch <[email-masked]> on behalf of Paul Kyzivat
> <[email-masked]>
> *Sent:* Friday, September 30, 2016 10:36 PM
> *To:* [email-masked]
> *Subject:* Re: [dispatch] draft-schulzrinne-dispatch-status-unwanted
>

---

From: Henning Schulzrinne <[email-masked]>
Date: Sat, 1 Oct 2016 03:31:24 +0000

I'd envision two hang-up buttons: the usual one and the "spam" one. Some third-party Android dialer apps already do something like this, and Nougat apparently has a related feature.

________________________________
From: Paul Kyzivat <[email-masked]>
Sent: Friday, September 30, 2016 11:24 PM
To: Henning Schulzrinne; [email-masked]
Subject: Re: [dispatch] draft-schulzrinne-dispatch-status-unwanted

        Thanks,
        Paul