How to Prevent Spoofed Robocalls with STIR/SHAKEN– Role of an SBC

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Telecom firms and communication service providers have been largely affected by the rise in robocalls and spam calling as they are frequently answerable to regulators regarding their efforts to combat illegitimate calls.

Do you know, nearly half of all mobile calls in the United States are robocalls? Isn’t that a quite big number? This figure varies from country to country. Before going deep into the ways to prevent Robocalls, let’s understand what exactly is a Robocall?

A robocall is a type of phone call, which delivers pre-recoded message through an automated dialer. It’s a common belief that robocalls are from telemarketers or even scammers, but they can also be used by deliver alerts and awareness.

Robocalls are usually categorized in the following:

  • Telemarketing
  • Scams
  • Payment Reminders
  • Alerts

However, not all of these are cause of concern as users will not get impacted by alerts or reminders. Only the spam calls generated by spammers affects the most.

Spoofing is used by many robocallers to trick your subscribers to answer their mobile phone. When the caller ID is changed by the robocaller, so that the call recipient sees a familiar number is known as spoofing.

For example; the call will look like it’s coming from the reliable organization or a phone number that’s similar to your subscriber. Main motive is to fetch the personal details like Bank or Credit Card information of the call recipient and indulge in cybercrime.

So what options carriers has to prevent these Robocalling? In United States, the Federal Communications Commission (FCC) has notified carriers to implement call authentication measures by adopting STIR/SHAKEN standards.

Implementing STIR/SHAKEN with a Session Border Controller

Deploying an SBC is one of the most effective measures to mitigate these fraudulent calls through STIR/SHAKEN framework.

Secure Telephony Identity Revisited (STIR) framework is developed by Internet Engineering Taskforce (IETF) that defines a signature to verify the calling number and its transmission on SIP.

On the other hand Signature Based Handling of Asserted Information Using toKENs (SHAKEN) is another framework created to provide an application profile for service providers applying STIR.

How STIR/SHAKEN works

In simple terms, the call originating carriers will sign the caller IDs as legitimate and validated by other carrier before it reaches the users.

There are several component of STIR/SHAKEN  but the main element is the SIP headers of each originating call will carry an encrypted token validating the sender and the caller ID authenticity which can be decrypted and confirmed at the terminating end.

With a SBC, service providers can combat spoofed robocalls through caller id authentication. STIR/SHAKEN solution in a Session Border Controller aids in authentication, signing, verification of calls.

A Common Deployment Architecture for SHAKEN

  • Calls are signed by the interconnecting Session Border Controller as they leave the originating carrier’s network
  • The interconnect SBC verifies the Call as they enter the terminating carrier’s network

SBC is one of the most robust solutions in the industry to prevent unwanted robocalling. Communication providers are rapidly adopting this solution in their network to not only prevent robocalling but also various types of telecom frauds. Download this whitepaper to know about various types of telecom frauds.

The Author

Abhijeet Guha

Abhijeet is a content marketing professional, who loves to write on various topics related to the telecom industry.
Abhijeet Guha