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Glossary · Compliance

What is Snowshoeing?

  • Also called: number rotation, spreading call volume

Reviewed by Sujan ThapaliyaLast updated

Definition

Snowshoeing is spreading calling or messaging volume thinly across many numbers to stay below the thresholds that trigger spam labelling. Carriers and analytics providers treat it as deliberate evasion rather than as a legitimate distribution strategy.
The three STIR/SHAKEN attestation levels, which underpin how snowshoeing behaves in practice: A asserts both that the carrier knows the customer and that the customer may use the calling number, B asserts the customer only, and C asserts neither. A shared number pool can reach B at best, which is why number ownership keeps recurring in these definitions.
Attestation is the backdrop to most caller-ID and deliverability terms, snowshoeing included.

In practice

How snowshoeing actually works

The name comes from distributing weight across a wide surface to avoid sinking. Detection is straightforward now: many numbers from one originator, each with low volume, short average duration and similar calling patterns.

It also breaks the business case for the numbers. Callbacks land on numbers nobody monitors, and the reputation that a consistent identity would have built never accumulates.

The legitimate version is capacity planning: a number of owned numbers proportionate to genuine regional presence, each with sensible daily caps and a working callback path.

The pattern is also self-defeating commercially, which is the part operators miss. Spreading calls across forty numbers means forty numbers nobody monitors, so every callback — the highest-intent call any campaign produces — reaches an unattended line. The technique loses the conversations it was meant to protect.

Worked example

Forty numbers each placing thirty calls a day, all from one originator, with 20-second average durations. Each number looks harmless; the pattern across them is what gets scored.

Snowshoeing: common questions

Is rotating numbers the same as snowshoeing?
It becomes snowshoeing when the purpose is to stay under detection thresholds rather than to serve a real regional presence. Analytics engines score the pattern, not the intention.
How do carriers detect it?
By correlating numbers back to one originator and looking at the shape of the traffic: many numbers, low volume each, short durations, similar time-of-day patterns.
What should I do instead?
Fix the calling pattern that caused labelling in the first place — volume per number, call duration, list quality — and hold fewer numbers with real callback paths.

Sources

  1. Combating Spoofed Robocalls with Caller ID Authentication — Federal Communications CommissionThe STIR/SHAKEN framework, the attestation levels carriers sign calls with, and the mandate requiring providers to authenticate caller ID.
  2. 47 U.S.C. § 227 — Restrictions on the use of telephone equipment — Cornell Legal Information InstituteThe Telephone Consumer Protection Act itself — the consent requirements, calling-hours limits, and private right of action.
  3. ITU-T Recommendation E.164 — The international public telecommunication numbering plan — International Telecommunication UnionThe international number format, the 15-digit maximum, and how country codes and national numbers compose.

See snowshoeing in the product

Branded caller ID puts your business name on the recipient's screen instead of a bare number. In North America it works through CNAM, the caller-name record attached to a number, combined with STIR/SHAKEN signing that lets the terminating carrier trust the call is really from you.

Explore branded caller idGet early access