STIR/SHAKEN is a regulatory framework designed to help combat illegal robocalling. With STIR/SHAKEN, service providers will sign and authenticate phone calls using different Attestation or “trust” levels depending on who the call is coming from. Further information can be found at FCC.Gov/call-authentication.

This is a summary article detailing basic facts about STIR/SHAKEN, and how the framework is implemented on the VI network.

All details presented in this document are for informational purposes only and do not constitute any form of legal or regulatory advice. VI highly recommends that all voice services providers seek consultation from legal and/or telecom compliance experts regarding your company’s obligations for STIR/SHAKEN and all other FCC rules and regulations.

Frequently Asked Questions

What are the different levels of attestation?

• Full Attestation (Attestation A) - The service provider has confirmed the user that is making the call is authorized to use the calling number.

• Partial Attestation (Attestation B) - The service provider has authenticated the user but cannot verify that they are authorized to use the calling number. Calls using ANIs (Calling Numbers) that have been purchased from another provider will receive this level of attestation.

• Gateway Attestation (Attestation C) - The service provider can authenticate the call’s origination but cannot verify the source of the call. 

Is VI currently signing my calls? What level of attestation are my calls receiving?

Yes, VI signs and provides attestation for all unsigned outbound calls that are sent to our voice network, free of charge.

If you are a voice service provider that is not signing your own calls, VI will provide attestation as an intermediate provider, and apply B or C level attestation to the attempt. Enterprise/non-service provider customers will typically receive A attestation since VI is the direct service provider.

Since VI has completely implemented STIR/SHAKEN, can I list this status for my own voice network in the FCC’s Robocall Mitigation Database?

For the vast majority of voice service providers, VI’s STIR/SHAKEN implementation status will have no effect on your company’s own status. VI highly recommends seeking consultation from a legal and/or telecom compliance expert to ensure that you are providing your company’s correct status in the Robocall Mitigation Database. Recommendations regarding consultation services can be found in VI’s STIR/SHAKEN Implementation Guide.

Does VI offer any Hosted STIR/SHAKEN call signing solutions for Service Providers?

Yes, more information regarding our Hosted STIR/SHAKEN call signing solution is available here.

I’m a service provider with another underlying carrier besides VI, and that carrier says that I’m covered for STIR/SHAKEN since they sign my calls with their own certificate. Why would I need VI’s Hosted STIR/SHAKEN solution?

As of 2023, the FCC expects the vast majority of voice service providers to be providing attestation for the calls that originate from their network, the only exception being small facilities-based service providers, who have until June 30th, 2023 to implement STIR/SHAKEN.

VI’s Hosted STIR/SHAKEN solution differs from carriers that are signing your calls as an intermediate provider because we’re empowering you to sign your own calls; there’s no reliance on VI or other intermediate providers to provide attestation for you. This is the key differentiator that makes your business compliant and allows you to attest to ‘Complete STIR/SHAKEN Implementation' in the FCC’s Robocall Mitigation Database.

I have implemented STIR/SHAKEN on my voice network and provide attestation for my outbound traffic. Is there any further action required in regards to VI?

No, VI will pass your headers without any alterations. No action required.

What steps are required to receive headers on inbound calls?

By default, VI does not send inbound headers since these additional headers can cause fractured packets, and subsequently cause calls to fail if your network and/or firewall is not prepared to receive them.

Service providers that have implemented STIR/SHAKEN can request these headers to be sent by Creating a Support Ticket. Please be ready to include the list of Endpoint Groups that you would like to receive the headers for.

Inbound Verification (STIR/SHAKEN verification results)

You may configure Inbound Verification at the Endpoint Group-level. The options are verstat, which sends STIR/SHAKEN verification results in the P-Asserted-Identity field, or header, which passes the entire STIR/SHAKEN header to your network (TCP Transport Type is recommended for this). For more information, please see our Wiki article on Endpoint Groups.

Will VI provide attestation for invalid Caller IDs?

No, outbound calls made from an invalid source number will be rejected with a 503 by VI’s network.