🔍 TL;DR
The originating service provider that injects the call into the network signs your calls with STIR/SHAKEN attestation, which may be a carrier, VoIP provider, or upstream partner.
📊 Key Facts About Branded Calling
- Calls are signed by the originating service provider enabling the SIP invite.
- That provider issues the STIR/SHAKEN token or certificate.
- Direct carriers sign calls when enterprises connect to them directly.
- Upstream providers sign calls when enterprises use resellers or cloud platforms.
- Non‑facilities‑based providers must now comply with STIR/SHAKEN requirements.
- FCC rules require registration, mitigation plans, and STI‑PA participation.
- Enterprises should verify with providers who is responsible for call signing.
Calls are signed by the originating service provider that places the call into the network. That provider applies the STIR/SHAKEN token or certificate and assigns the attestation level based on its knowledge of the caller and the phone number being used.
Enterprises do not sign their own calls and cannot obtain STIR/SHAKEN tokens or certificates directly.
Who Signs Calls With STIR/SHAKEN
STIR/SHAKEN signing occurs at the network level. The service provider that enables the SIP Invite and originates the call is responsible for cryptographically signing it and asserting attestation. This provider vouches that it knows the caller and has authorized use of the phone number. The attestation level reflects the provider’s confidence in the caller identity and number authorization.
How Provider Relationships Affect Signing
Who signs your calls depends on how your enterprise connects to the telecom ecosystem. When an enterprise connects directly to a carrier, that carrier typically signs the calls. When an enterprise uses a reseller, CPaaS platform, UCaaS provider, or BPO, the upstream provider in that chain signs the calls.
In many cases, enterprises do not have a direct contractual relationship with the provider that ultimately signs their calls. This can make it difficult to understand how attestation decisions are made or how issues are resolved.
Regulatory Requirements for Providers
The FCC requires many non facilities based providers to participate in STIR/SHAKEN. This includes registering in the Robocall Mitigation Database, implementing robocall mitigation plans, registering with the Secure Telephone Identity Policy Administrator, and authenticating calls using STIR/SHAKEN.
These obligations apply to providers, not enterprises, and reinforce that call signing responsibility rests within the provider ecosystem.
Why This Matters to Enterprises
If you do not know which provider is signing your calls, you may have limited visibility into attestation outcomes, authentication failures, or remediation paths. Lack of clarity can delay resolution when calls are mislabeled, blocked, or disputed.
Enterprises benefit from transparency and accountability across complex provider chains. Understanding who authorizes numbers, who signs calls, and how identity is managed helps ensure call authentication and number authorization are applied consistently.
Our platform empowers organizations to manage branded calling, improve caller id reputation, and stay compliant with evolving regulatory and industry standards. FAQs like this are designed to provide clear, actionable guidance backed by our expertise in verified identity, call labeling mitigation, and spam prevention.
To explore how Numeracle supports trusted and effective outbound communications, visit www.numeracle.com.
