The STIR/SHAKEN mandate was established by the U.S. Federal Communications Commission (FCC) to reduce the number of illegal robocalls placed to U.S. telephone customers by making it easier to verify that a caller is who they claim to be. The framework certifies or attests the source of a call and confirms the caller’s right to use the calling number.

In this framework, calls are signed (attested) by the originating carrier and verified by the terminating carrier. For the system to function properly, there are three attestation levels:

• Full Attestation (A) — The service provider has authenticated the calling party and they are authorized to use the calling number.
• Partial Attestation (B) — The service provider has authenticated the caller’s identity but cannot verify that they are authorized to use the calling number.
• Gateway Attestation (C) — The service provider has validated only the source from which the call was received but cannot authenticate the caller.

While STIR/SHAKEN alone does not stop illegal spoofing or robocalling, it significantly improves the ability to trace the origin of fraudulent calls and reduce call spoofing across networks.

Genesys Implementation of STIR/SHAKEN

Genesys Cloud Voice (GCV) is fully compliant with the FCC’s STIR/SHAKEN mandate. GCV signs and attests all outbound SIP calls directly, ensuring that calls placed through Genesys are verified under the STIR/SHAKEN framework.

• Calls originating from Genesys Cloud Voice numbers receive Full Attestation (A), confirming that the caller has been authenticated and is authorized to use the number.
• Calls using Bring Your Own Carrier (BYOC) numbers through GCV receive Partial Attestation (B), as GCV can authenticate the customer but cannot verify ownership of third-party numbers.

Genesys continues to collaborate with telecom partners and analytics providers to enhance call authentication, call reputation, and transparency across the voice ecosystem.

FAQs

How does the attestation level affect call completion?

Our expectation is that the attestation level will have little to no affect on call completion.

Will calls be blocked if they don’t get an “A”?

No, in fact, carriers don’t want to block any calls except for illegal calls. They make money on minutes for complete calls!

Will the attestation level affect how calls are labeled (for example “Spam Likely”)

Potentially, but not likely initially. Call “labeling” is a matter of analytics used by the terminating phone carriers and attestation level may impact algorithms at some point.

Who is responsible for labeling calls at the receiving party’s end?

The terminating carrier (for example, the wireless carrier) provides caller ID, caller name, or other labels as part of their service.

Will all calls in the US have a STIR/SHAKEN attestation?

No, only calls originated as SIP calls will be signed. Traditional TDM infrastructure does not currently have a technical mechanism to implement STIR/SHAKEN. That also means that calls originated as SIP that traverse TDM PSTN elements will lose the signature and potentially be re-signed as SIP.

Why are some of my outgoing calls already being labeled as “Spam Likely” or some other designation?

Downstream analytics vendors use various techniques to label calls, including crowd-sourced complaints, unusual calling patterns (high-volume, rapid call rates), and so forth, which can indicate spam. Also, legitimate businesses may already be victims of spoofing (bad actors using someone else’s numbers).

What can a customer do to maximize their call completions?

Use valid PSTN phone numbers assigned to the customer. Register their numbers with Free Caller Registry key analytics so vendors know who the customer is and they can take that into account in the “labeling” algorithms. The key vendors that work with the major wireless carriers are First Orion, Hiya, and TNS.

How does this affect BYOC customers who bring their own PSTN to Genesys?

Customers need to consult with their carrier about how their calls will be signed.

Can Genesys tell how a call is viewed at the receiving party?

No. Originating carriers do not know the routing on a call-by-call basis. Any particular call can traverse multiple hops through the PSTN, and even different routes at different times.

Where can I find information from the FCC concerning STIR/SHAKEN?

For more information on STIR/SHAKEN, see the Combating Spoofed Robocalls with Caller ID Authentication article on the FCC website.