STIR/SHAKEN and robocall mitigation filing deadlines


Tricia McConnell


What’s happening?

STIR/SHAKEN is a robocall mitigation framework designed to reduce fraudulent robocalling and illegal phone number spoofing in the U.S. The deadline for STIR/SHAKEN compliance is June 30, 2021. Smaller providers (less than 100K subscribers) currently have a 2-year extension to June 30, 2023 but the FCC has proposed reducing this time to only 1 year. 

The FCC has also recently launched the Robocall Mitigation Database (RMD) for service providers to formally file their robocall mitigation plans. The deadline for service providers to complete this registration is June 30, 2021. 

Important: The FCC has directed carriers and service providers to block calls they may receive, including internationally originated traffic, from voice service providers not registered in the RMD after September 28, 2021. 

Who’s impacted by STIR/SHAKEN and the upcoming deadlines?

Voice service providers routing traffic to or from US phone numbers, including internationally-based providers. 

What do I need to do? 

  1. File a robocall mitigation plan in the FCC’s RMD. While Bandwidth can't provide specific legal advice about what to include in your plan, the Robocall Mitigation Database External Filing Instructions from the FCC can help guide you in this process.
  2. Be prepared to manage network and traffic exchange arrangements with new carrier blocking behaviors in mind. 

What has Bandwidth done to prepare for STIR/SHAKEN?

Bandwidth deployed STIR/SHAKEN in our network in December 2019. Since then, we’ve completed STIR/SHAKEN interops with Verizon Wireless, Comcast, T-Mobile/Sprint, AT&T, Peerless, and more. 

We currently sign over 4.5B calls each month on behalf of our global customers including Bandwidth International (formerly Voxbone) customers using U.S. numbers. In December, we were granted an exemption by the FCC in recognition of Bandwidth’s significant voluntary efforts to deploy STIR/SHAKEN well in advance of the Commission’s upcoming June 30 deadline. 

How is Bandwidth signing calls on behalf of its customers?

  • Outbound calls from Bandwidth customers using Bandwidth U.S. phone numbers are signed with “A” or full attestation. 
  • Outbound calls from Bandwidth customers using non-Bandwidth U.S. phone numbers are signed with “B” or partial attestation. 
  • Bandwidth does not currently sign any calls with “C” or gateway attestation. 

We strongly recommend that our customers consult with legal counsel to determine if the above, combined with the filing of a robocall mitigation plan, satisfies their regulatory requirements for STIR/SHAKEN. 

Want to learn more about STIR/SHAKEN and new features available with Bandwidth? Please see our full support article or contact your Account Manager. 

What if I’m signing my own calls for STIR/SHAKEN? 

Approved STIR/SHAKEN service providers who are authenticating and verifying their own traffic can use Bandwidth as an intermediate service provider at no charge. You can enable our Transit Identity Service directly in the Bandwidth Dashboard. Bandwidth will act as an intermediate service provider and convey the SIP header information for both inbound and outbound traffic.

Bandwidth International (formerly Voxbone) customers who are also approved STIR/SHAKEN service providers should contact their Account Manager or Customer Success Manager to migrate their accounts to the Bandwidth Dashboard in order to enable this service. 

Does Bandwidth provide the verification results on inbound traffic? 

U.S. Origination customers can now enable our Inbound Verification Service in the Bandwidth Dashboard. This feature provides STIR/SHAKEN verification results to service providers in order to make decisions to either block calls or terminate them to the end user.

A similar capability is currently in development for Bandwidth International customers and will be enabled in the Bandwidth International platform at the account level. Please contact your Account Manager or Customer Success Manager for more information. 

Some of my calls will be signed with “B”. Are they going to be blocked? 

Call blocking determinations are made in a number of different ways, including the use of proprietary call analytics services. While Bandwidth is focused on avoiding inappropriate blocking by downstream terminating providers, Bandwidth doesn't anticipate that signing calls with “B” will be the sole factor in such call blocking treatment. 

Nevertheless, in order to better ensure that false-positive blocking is minimized, Bandwidth is a strong proponent of Certificate Delegation. Certificate Delegation would allow our customers to reference a valid certificate from the owner of the phone number so that the call could be signed with “A” attestation. Bandwidth’s product team is currently working within ATIS to push for the adoption of the industry standard this year

In general, call delivery or blocking issues with a specific Bandwidth phone number or carrier should be reported to Bandwidth by opening a support ticket. Our Technical Assistance Center (TAC) will investigate and may be able to provide options to help address the problem with the specific terminating carrier. 

What else is Bandwidth planning for STIR/SHAKEN? 


Features like call forwarding or the ability to ring multiple devices simultaneously change the destination called number and break the STIR/SHAKEN authentication process. The ATIS standard for “div” PASSporT allows service providers to confirm a call has been legitimately retargeted. Bandwidth is committed to implementing additional STIR/SHAKEN standards as they emerge.


Canada’s deadline for STIR/SHAKEN is November 2021. Please note that the certificates required to sign calls originating from Canadian providers are issued from different Certificate Authorities than in the U.S. Bandwidth is currently developing a solution to meet Canada’s deadline. 

Additional resources

Note: STIR/SHAKEN isn't deployed on legacy network devices such as inbound/outbound gateways "Bandwidth 7", "Bandwidth 9", and "Bandwidth Edge" devices. Calls traversing these routes won't be signed. If you'd like to migrate to STIR/SHAKEN devices, please reach out to your Bandwidth Support Team. 

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