SIP Calling Number Verification Display (STIR/SHAKEN)

Last Updated : Oct 06, 2023 |
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After verifying the calling number, the authentic incoming calls will proceed with the regular call routing process. After the verification process is completed, the verified information will be displayed on the endpoints.
The customization is achieved by using the specific characters in the Code field of short codes or the Incoming Call Line Identification field of incoming call routes.
See the following table for the list of characters associated with the verification:
Character
Meaning
Description
V
Validation passed
It matches calls where the verstat value is set to TN-Validation-Passed plus the attestation level.
If required, the level of attestation to match can be specified. Attestation levels are as follows:
  • A indicates Full Attestation.
  • B indicates Partial Attestation.
  • C indicates Gateway Attestation.
X
Validation failed
It matches calls that failed verification, meaning the call verstat value is set to TN-Validation-Failed.
?
No Validation
It matches calls that do not have any verification results or where the verstat value received is NO-TN-Validation.
The result of the verification process is then indicated in the call headers using a verstat value:
  • TN-Validation-Passed plus an attestation level (see the table below). For example, TN-Validation-Passed.
  • TN-Validation-Failed plus an attestation level (see the table below). For example, TN-Validation-Failed.
  • No-TN-Validation
Attestation Level
Description
A
Full Attestation
The customer is known, and the calling number is associated with that customer.
  • When no authentication level is indicated or can be obtained, the IP Office treats the call as attestation level A.
B
Partial Attestation
The customer is known. However, the number is not associated with that customer. For example:
  • The customer is forwarding a call with an original calling number that is not associated with them.
    The call originates from another known ITSP, which is common for international calls.
C
Gateway Attestation
The call has come through a trusted source, but the original customer and number are unknown.