SIP Calling Number Verification (STIR/SHAKEN)

Last Updated : Sep 16, 2022 |
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For calls with are allowed following calling number verification, normal incoming call routing is applied. However, that routing can be made to be specific to the verification result and attestation level of the call.
This is achieved using the following characters in the Code field of short codes or Incoming CLI field of incoming call routes:
Character
Meaning
Description
P
Passed
Matches calls where the verstat value is set to TN-Validation-Passed plus the attestation level. For example, TN-Validation-Passed-A.
If required, the specific level of attestation to match can be specified. That is done by following the P character with the required level or levels inside " " marks. For example:
  • P"A" matches calls with an attestation of A.
  • P"B" matches calls with an attestation of B.
  • P"AB" matches calls with an attestation of A or B.
F
Failed
Matches calls that specifically failed verification. That is, the call's verstat value is set to TN-Validation-Failed.
Q
Unknown
Matches calls which do not have any verification result or where the verstat value received is No-TN-Validation.

Example Incoming Call Routing

In this example, the system has the following incoming call routes are defined for calls to the business's main sales number. Apart from the setting below, each of the incoming call routes has the same settings and matches the incoming group ID used by the SIP trunks URI.
Incoming Call Route
Incoming CLI
Destination
Description
1.
P"A"
Hunt Group
The business's sales hunt group.
2.
blank
Auto-Attendant
The business's auto-attendant. The use of an auto-attendant to answer calls deflects automated calls with potential spoofed caller ID numbers but still allows callers to select to be connected to the sales group via the provided auto-attendant options.
3.
P"B"
Auto-Attendant
4.
Q
Auto-Attendant
5.
F
Barred
A short code set to the barred feature.
The following calls to the sales number are received:
Incoming Call Details
Incoming CLI
Attestation Level
Destination
1.
111
A
A fully validated call. The call details match the 2nd call route only. Therefore, the call is routed the sales hunt group.
2.
222
B
A partially validated call. The call details match both the 2nd and 3nd call routes. However, the 3rd match is more precise, so the call is routed to the auto-attendant.
3.
333
C
The call details match both the 2nd and 5th call routes. However, the 5th match is more precise, so the call is routed to the barred short code.
4.
444
None
A call with no attestation level. The call details match the 2nd and 4th call routes. However, the 3rd match is more precise, so the call is routed to the auto-attendant.

Calling Name Display

Calling number validation only validates the caller's number, not the display name information provided with the call.
Related links
SIP Calling Number Verification (STIR/SHAKEN)