A-Level STIR/SHAKEN Attestation Is an ASR Variable, Not a Compliance Checkbox

Call-analytics data from platforms including TransNexus and YouMail consistently shows that calls carrying STIR/SHAKEN A-level attestation receive "Scam Likely" labels at materially lower rates than B or C-attested calls traversing the same terminating networks. For a dialer running tens of thousands of outbound calls per day, that difference appears directly in your answer-seizure ratio (ASR), the single metric your campaign managers use to judge whether a trunk is performing.

STIR/SHAKEN was designed to authenticate caller identity, not to hand compliant carriers a performance edge over resellers. But the analytics-driven call-filtering systems deployed by Verizon, T-Mobile, and AT&T consume the attestation level as one scoring input alongside number reputation and call-behavior signals. The practical result: the attestation level your originating carrier signs onto your calls is a performance variable, not just a regulatory line item.

What the Three Attestation Levels Actually Mean

A-level attestation means the originating carrier has verified that the calling party is authorized to use the number it is presenting. B-level means the carrier authenticated the call origination but could not verify the number assignment to that specific customer. C-level means the carrier cannot attest to either. A reseller pulling capacity from a wholesale provider typically passes B or C because it does not control the number-assignment database it inherited from upstream. The attestation is only as strong as the weakest link in that chain.

This gap produces expensive downstream problems. A contact center watches ASR decline, calls a number-reputation rehab service, pays monthly per-DID fees to clean numbers that may or may not recover, then restarts the cycle a few months later. The root cause is rarely the DID itself. The root cause is that the originating carrier was never in a position to sign A-level in the first place. Charging you for reputation repair after creating the conditions for reputation damage is a tidy business model for them.

Why the Originating LEC Controls the Outcome

Greenway Communications holds FCC LEC authority and signs A-level attestation in-house against our own DID inventory. There is no upstream carrier whose attestation policy we inherit. When a call originates through our network, we control the number assignment, the STIR/SHAKEN signing key, and the Identity header that travels with the call to the terminating switch. That chain of custody is what A-level attestation is supposed to represent, and we own every link of it.

Most voice resellers cannot say the same. The PASSporT token embedded in the SIP Identity header records both the attestation level and the originating provider's identity. Analytics engines at terminating carriers read it. Contact centers whose carriers can only sign B or C are running at a structural disadvantage on every campaign, regardless of what their carrier tells them about "clean routing" or "premium interconnects."

The Math on Getting This Right Up Front

Number-reputation services typically charge per active DID per month to monitor and attempt remediation across the major analytics platforms. At several hundred active DIDs, that cost compounds quickly and treats the symptom while leaving the attestation gap open. Migrating to a carrier that originates A-attested calls removes the justification for that remediation spend on the bulk of your inventory and recovers ASR without the repeating cycle.

We run A-level attestation on our own internal outbound traffic because we operate under the same economics we ask our customers to trust. When something goes wrong on a call we signed, there is no upstream carrier to escalate to. We own it. That accountability is why attestation level matters operationally, not just on a compliance checklist.

For rate-deck and DID pricing details, see our carrier pricing page, or reach out directly to talk through your trunk and attestation setup. Integrity in Telecom starts at the origination layer.