[VoiceOps] FAS Dead Air

[Calvin Ellison]

Yes, this is traffic to the USA. We're the service provider, so we have no
control over the ANI used, and there's been no obvious pattern there. The
complaints we get cover pretty much every carrier in our short duration
LCR. Most of those complaints reach us from aggregators so we're usually a
few parties distant from the source complaint. Of course, no one ever
provides packet captures, and we're not anchoring media so we can't see it
happening.

Our ULC don't really do much to help in the long term. It's usually "unable
to reproduce, temporarily blocked RN or dialed number over the offending
route, will escalate to peer", repeated a dozen times a week.

I have a few hypotheses:
1. Downstream carriers are taking advantage of flat rates from
international carriers, and media is getting lost bouncing between
continents. We get plenty of other complaints like "why did my call to USA
have a Russian media IP?", so this doesn't seem implausible.

2. Some intermediate is watching for traffic already getting blocked as
robocalls and diverting it to their checking account. There are plenty of
very obvious reject codes out there like "503 Blocked Caller ID", "503
BLOCKED", and "503 ANI BLOCKED". Any intermediate carrier with an ounce of
analytics could look for those and ANI with low ASR, high 404 rates, etc.
and start diverting traffic no one is going to miss on the receiving end.

3. Some popular dialer application is doing tricks with media that
non-complaint system dislike. I've seen some using INVITE with c = 0.0.0.0
or "a=inactive" so they can conserve bandwidth on pre-session media/ring
phase, then re-INVITE with a proper SDP after 200 OK.

Regards,

*Calvin Ellison*
Senior Voice Operations Engineer
calvin.ellison at voxox.com
+1 (213) 285-0555

-----------------------------------------------
*voxox.com <http://www.voxox.com/> *
5825 Oberlin Drive, Suite 5
San Diego, CA 92121
[image: Voxox]


On Thu, Nov 7, 2019 at 2:37 PM Dovid Bender <dovid at telecurve.com> wrote:

> Is this in the US? Are you seeing the same across multiple vendors? If you
> have a pool of say 100 numbers and you use them randomly for outbound calls
> is there any difference?
>
> On Tue, Nov 5, 2019 at 9:11 PM Calvin Ellison <calvin.ellison at voxox.com>
> wrote:
>
>> Is anyone else seeing an increase in customer complaints regarding Dead
>> Air or FAS in general?
>>
>> We don't get this complaint from our conversational clients, but there's
>> been a near-daily stream of them from our short duration/dialer clients.
>> I'm wondering if someone out there is targeting ANI or SDP connection IP
>> and giving them special treatment. Is there a robocall blocking solution
>> that is connecting calls to nothing?
>>
>>
>>
>> Regards,
>>
>> *Calvin Ellison*
>> Senior Voice Operations Engineer
>> calvin.ellison at voxox.com
>> +1 (213) 285-0555
>>
>> -----------------------------------------------
>> *voxox.com <http://www.voxox.com/> *
>> 5825 Oberlin Drive, Suite 5
>> San Diego, CA 92121
>> [image: Voxox]
>> _______________________________________________
>> VoiceOps mailing list
>> VoiceOps at voiceops.org
>> https://puck.nether.net/mailman/listinfo/voiceops
>>
>
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