The Attestation Problem Nobody Is Talking About
Your outbound dialing infrastructure can be perfectly optimised — the right trunks, the right routing rules, the right carrier mix. And yet your calls still go unanswered. Not because of volume. Not because of list quality. Because the person on the other end sees an unverified number and simply doesn’t pick up — or their carrier already filtered the call before it ever rang.
STIR/SHAKEN and outbound contact center performance are directly connected across all of North America. The attestation level assigned to your outbound calls — determined entirely by your telecom provider — has a measurable impact on whether those calls are delivered, displayed, or silently dropped. And most outbound operators have no idea what level their calls are actually getting.
How multi-trunk architecture and prefix-based routing in Genesys Cloud lifts your answer rates on a call-by-call basis.
What STIR/SHAKEN Actually Does
STIR/SHAKEN is the North American framework for digitally signing outbound voice calls. It verifies that the number displayed is legitimate and that the carrier originating the call has the authority to use it. Both the FCC (US, mandated 2021) and the CRTC (Canada, mandated 2021) require all major carriers to sign and verify calls on IP-based SIP networks.
STIR (Secure Telephony Identity Revisited) defines how calls are signed with a digital certificate. SHAKEN (Signature-based Handling of Asserted information using toKENs) is the protocol carriers use to exchange and verify those certificates as a call moves across networks. Together, they were designed to combat spoofing — but their downstream effect on legitimate high-volume outbound operations is just as significant.
When your outbound call leaves Star Telecom’s network, we attach a signed digital certificate to the SIP call signalling. That certificate travels with the call across intermediate carriers to the terminating network. The receiving carrier validates the certificate and uses it to decide how to label — or whether to deliver — the call to the recipient.
The key variable is your attestation level: the confidence rating your originating carrier assigns. It is the single biggest factor in whether your call arrives with a “Verified” display, a warning label, or never rings at all.
The Three Attestation Levels
STIR/SHAKEN defines three levels of attestation. The level your carrier assigns is determined by one thing: whether they own and control the number being used to make the call.
Your carrier’s attestation level isn’t a compliance checkbox. It’s a trust signal that travels with every outbound call — and it directly determines whether your customers pick up.
The Hidden Problem: Signing at A Doesn’t Guarantee A Is Received
Here is the part most vendors will not tell you — and the reason the Star Telecom commitment goes further than simply “we support Full Attestation.”
A call can leave your originating carrier signed at A and arrive at the next carrier in the chain at B, C, or unsigned. This happens when an intermediate carrier in the routing path does not properly honour or pass through the STIR/SHAKEN certificate. It’s more common than the industry acknowledges, particularly on calls that cross multiple network boundaries between Canada and the US.
The vendor question most buyers never ask is not “do you sign at A?” — almost every carrier will say yes. The question is: “Can you audit what attestation level was actually received by the terminating carrier?” That requires visibility into the full call path, not just the origination leg.
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1Do you own the numbers you provision for us? If the answer is “we source them from a partner” or “they’re ported in,” Full Attestation (A) is likely not possible.
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2What attestation level do our calls leave your network at? Get this in writing. “We support STIR/SHAKEN” is not the same as “we sign at A.”
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3Can you show us what attestation level was received by the next carrier in the chain? This is the critical question. Signing at A on departure means nothing if the certificate is stripped in transit.
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4Do any of our routing paths cross international gateways? International gateway entry points typically result in Gateway Attestation (C) regardless of how the call originated.
How Star Telecom Delivers — and Proves — Full Attestation
Star Telecom owns the numbers we provision. Every outbound call leaves our network signed at Full Attestation (A). And we can provide documentation of what was received by the next carrier in the chain — not because we’re unusual, but because we believe this is the standard every outbound contact center should hold their provider to.
Star Telecom provisions numbers from our own direct inventory for both Canadian and US outbound campaigns. We don’t resell ported numbers or source inventory through intermediaries. Ownership is the non-negotiable prerequisite for Full Attestation — and we meet it on every number we provision.
Every call leaves our network with a STIR/SHAKEN digital certificate signed at the A level. The certificate identifies Star Telecom as the originating carrier, confirms number ownership, and travels end-to-end through the SIP signalling to the terminating carrier. This is not a best-effort commitment — it is the baseline for every client.
We actively monitor attestation levels across the call paths we manage. Where intermediate carrier behaviour introduces degradation, we identify it, document it, and work to resolve it — either by reconfiguring the routing path or by flagging the problematic transit carrier. Clients can request attestation reports for their outbound traffic at any time.
Attestation signing happens at the carrier layer, transparently, before a call ever touches Genesys. Your dialer campaigns, outbound lists, and prefix-based routing rules operate exactly as configured. There is no additional setup inside Genesys — the protection is built into the infrastructure.
In the rare cases where ported numbers or specific routing scenarios prevent Full Attestation, we work with intermediate carriers to secure Partial Attestation (B) as the minimum. We do not allow outbound contact center traffic to leave our network at Gateway (C) or unsigned — full stop.
North America Today: Where STIR/SHAKEN Stands
Both the FCC and CRTC mandates have been in force since 2021. Enforcement is tightening on both sides of the border, and terminating carriers — particularly in the US — are becoming increasingly aggressive about filtering or labelling calls that arrive without Full or Partial Attestation. The trajectory is one-way.
| Scenario | Attestation at Origin | Risk of Degradation | Effective Impact |
|---|---|---|---|
| Star Telecom-owned numbers, direct routing | A — Full | Low — direct path, monitored | Best deliverability. Verified display on supported networks. |
| Ported or third-party numbers | B — Partial | Medium — depends on transit carrier | Clean delivery, no verified badge. Increasing filtering risk. |
| International gateway entry | C — Gateway | High — gateway entry defaults to C | “Spam Risk” labels. Calls may not be delivered. |
| CCaaS-bundled carrier, no direct ownership | B or C — varies | Unknown — rarely audited | Unpredictable. Most clients don’t know their actual level. |
| Star Telecom A-signed, unaudited transit carrier | A — at origin | Medium — passthrough not guaranteed | Requires active monitoring to confirm received attestation. |
The window to audit and correct your attestation posture is now. A carrier policy change or a tightening of CRTC or FCC enforcement does not come with advance warning. The contact centers who treat attestation as an operational variable — not a compliance footnote — are the ones who won’t wake up to a sudden unexplained drop in answer rates.
For more on the technical framework and CRTC background, see our full overview: STIR/SHAKEN in Canada: Everything You Need to Know.
Star Telecom will audit your current outbound traffic, map your full call path, and document the attestation level at every hop — not just at origin. Learn more about our SIP Trunking services →
Slug: stir-shaken-outbound-dialing-strategy · Categories: Telecom, Compliance, Contact Center Management · Related: STIR/SHAKEN in Canada overview · Part 1: Intelligent Dialing Rules