[VoiceOps] TMobile Sending Calls to LRN not Called Number

[Paul Timmins]

STIR/SHAKEN isn't implemented at all in TDM world. I've had problems on 
and off for years where a carrier will take SS7 traffic, send it over 
some janky arrangement that strips the GenericAddress parameter (where 
your actual destination number is hidden in the IAM - when you dip in 
SS7 you send the LRN as your CallingPartyNumber, set the flag indicating 
the call is dipped, and put the original TN in the 
GenericAddressParameter field) and then I get a pile of calls from 
specific carriers rocking into my LRN until I can get one of them to 
call their carrier and report the issue, which fixes it.

Our usual trick is the LRNs are routed to the NOC, so they have a 
procedure where if they start getting calls from all over the place 
looking for our customers, that they ask the caller to reach out to 
their phone company and have them write down a little spiel to put in 
their trouble ticket with their carrier ("Clear Rate says they are 
getting the calls without the generic address parameter, which is 
related to failure of local number portability in your switch or tandem 
provider" or something to that effect), which is typically pretty effective.

How often? Happens probably once a year since I set up the network in 
2007 we'll have a spate of them for a day.

-Paul

On 7/1/21 11:42 AM, Mary Lou Carey wrote:
> I'm not an expert in how STIR/SHAKEN is implemented in the TDM world, 
> but I've never heard of this happening until recently. I've heard 
> anything sent over the SS7 network has issues with the token being 
> dropped. Maybe the problem is bigger than just the token being 
> dropped.....maybe what they are doing is causing the called number to 
> be dropped as well! That's the only reason I can come up with as to 
> why one would get the LRN but not the called number.
>
> Just a thought,
>
> MARY LOU CAREY
> BackUP Telecom Consulting
> Office: 615-791-9969
> Cell: 615-796-1111
>
> On 2021-07-01 10:15 AM, Mark Timm wrote:
>> It’s not just T-Mobile, it’s Verizon, US Cell and Lumen
>> originations.  I believe it is traffic that Inteliquent back hauls.
>>
>>          [1]
>>
>>         Mark Timm​
>>
>>         Switch Engineer
>>
>>         Aureon
>>
>> 7760 Office Plaza Drive South
>>
>> West Des Moines
>>
>>         ,
>>
>> IA
>>
>> 50266
>>
>>         Mark.Timm at aureon.com
>>
>> 515‑830‑0478
>>
>>          [2]
>>
>>         www.Aureon.com [2]
>>
>>          [3]
>>
>>          [4]
>>
>>          [5]
>>
>>          [6]
>>
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>> From: VoiceOps <voiceops-bounces at voiceops.org> On Behalf Of Matthew
>> Sutton
>> Sent: Thursday, July 1, 2021 10:08 AM
>> To: voiceops at voiceops.org
>> Subject: [VoiceOps] TMobile Sending Calls to LRN not Called Number
>>
>> Anyone else seeing calls from TMobile coming in with the LRN as the
>> called number? The ISUP doesn't show the actual called number so we
>> can't route the calls.
>>
>> -Matthew
>>
>> Links:
>> ------
>> [1] https://www.aureon.com/
>> [2] http://www.aureon.com/
>> [3] https://www.facebook.com/aureon
>> [4] https://www.youtube.com/channel/UCv6xwRKJCouZM6FPQEJ6CMA
>> [5] https://www.twitter.com/aureon
>> [6] https://www.linkedin.com/company/aureon
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-- 
Paul Timmins
Clear Rate Communications
Direct: (248) 556-4532
Customer Support: (877) 877-4799
24 Hour Repair: (866) 366-4665
Network Operations: (877) 877-1250
www.clearrate.com

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