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Using CNAM for Reputation Management

The rise of nuisance calls has resulted in the emergence of sophisticated robocall blocking solutions. However, there is a large margin for error. Multiple reputation providers consider the presence of CNAM data as a crucial part of their scoring algorithms and Telo can help.

These solutions have helped to reduce the number of answered spam/scam calls while restoring the consumer’s trust in phone calls. By displaying “SPAM LIKELY” (or similar CNAM response) on the incoming call, consumers are better informed before answering. These solutions have been moderately successful in identifying calls as spam by evaluating the level of “nuisance activity” associated with each calling number. Carriers are widely deploying various nuisance call protection solutions to enable these safeguards for consumers. However, despite the comprehensive sets of data used to determine which calls are nuisance, there is a large margin for error.

False-positives, or incorrect flagging of permissible and legal calls is a challenging obstacle to overcome as they can often be difficult to detect. Enterprises fear that stricter call blocking solutions will damage their reputation and reduce answer rates. Consumers alike, worry that important incoming calls to their phone will be ignored. Since the responsibility (or blame) ultimately falls to the service provider, in cases where calls are incorrectly flagged, it is essential that carriers work together in order to mitigate false-positives, and maintain a high level of accuracy.

As it stands, each service provider has deployed different solutions and uses proprietary logic for detecting nuisance calls. This leads to a continuous and time-consuming challenge of determining the legitimacy of questionable calls. Service providers should be taking several steps to clear incorrectly flagged numbers:

  1. If it is reported that a number is incorrectly flagged, it must be determined which source(s) are flagging the number and why.

  2. If it is a permissible call, not being used for calling by a bad actor, the calling number should be added to a whitelist or “register” of numbers that have been cleared so that calls do not continue to be blocked.

  3. Last of all, as numbers frequently change underlying carriers via porting, whitelisted numbers need to be constantly monitored for potential changes in nuisance activity.


In a similar way, blacklisted or “known-bad” numbers should also be tracked. Unfortunately, this process is labor-intensive, and its effectiveness is limited. Why? Communication between carriers and service providers is minimal. Wide-spread adoption of automated processes for tracking and monitoring is necessary to address this problem. Unfortunately, as seen with STIR/SHAKEN, major changes within the telecommunications industry are difficult to implement due to the vast differences in switching platforms and technologies.

To minimize the detrimental effects of false positives, caller information should be disclosed to caller reputation solution providers as a matter of best practice. CNAM is one such data element that can be used to increase the accuracy of call flagging. Despite leaving consumers in the dark with regard to the calling party, multiple reputation providers consider the presence of valid CNAM data as a crucial part of their scoring algorithms.

Telo is in a unique position to facilitate the automated sharing of such information with several key participants. In addition to also being a CNAM provider to dozens of carriers, Telo has relationships with many of the leading caller reputation services. When subscriber CNAM data is updated with Telo, consumers will benefit from propagation to the major caller reputation providers. This will extenuate the potential for calls originating from these numbers to be flagged as nuisance.

By ensuring that caller reputation providers are updated with current CNAM information, carriers can easily realize the benefits of reputation protection without rethinking entire processes. With OpenCNAM, it is possible to clone CNAM updates and push them to Telo behind the scenes without disrupting the current update process. This information can then be shared with the caller reputation providers to increase the odds that valid callers don’t get incorrectly flagged.

In the absence of a unified strategy between carriers to boost the accuracy of call reputation solutions, Telo can help. Reach out to support@opencnam.com to speak with one of our CNAM experts and learn more about how OpenCNAM can play a part in resolving false-positives for your consumers.

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