Verstat Related Best Practices Mark Desterdick Verizon IPNNI

Verstat Related Best Practices Mark Desterdick Verizon IP-NNI Task Force May 2, 2018

Topics l Format – P-Asserted-ID for SIP and tel URIs – Various SIP methods l Granularity – Terminating Attestation Level Identification to terminating UA or CVT l Legitimate Privacy – CLIP/CLIR

P-Asserted-ID: SIP URI Format in P-Asserted_Identity (PAI) using a SIP URI - placement of verstat before the @ sign sip: +358 -555 -1234567; postd=pp 22; verstat=TN-Validation-Passed@foo. com; user=phone This is derived from the syntax for verstat in the P-asserted-id in Tel-URI format as defined in 3 GPP TS 24. 229 section 7. 2 A. 20. Reasoning: tel: +358 -555 -1234567; postd=pp 22; verstat=TN-Validation-Passed 1. verstat is a TEL URI parameter 2. Parameters are associated with a TEL URI per the syntax specified in RFC-3966 3. Parameters are associated with a SIP or SIPS URI per the syntax specified in RFC-3261 4. TEL URIs are mapped to SIP URIs as specified in RFC-3261

Verstat in Various SIP Methods Proposed verstat syntax in various SIP methods INVITE P-Asserted-Identity OR From: tel: +15617500080; verstat=TN-Validation-Passed P-Asserted-Identity OR From: sip: +15617500080; verstat=TN-Validation-Passed@foo. com; user=phone SUBSCRIBE Message Body Calling-party: tel: +15617500080; verstat=TN-Validation-Passed Calling-party: sip: +15617500080; verstat=TN-Validation-Passed@foo. com; user=phone NOTIFY Message Body Calling-Name: "BUSINESS 005" tel: +15617500080; verstat=TN-Validation-Passed OR Calling-party: "BUSINESS 005" sip: +15617500080; verstat=TN-Validation-Passed@foo. com; user=phone MESSAGE P-Asserted-Identity OR From: tel: +15617500080; verstat=TN-Validation-Passed P-Asserted-Identity OR From: sip: +15617500080; verstat=TN-Validation-Passed@foo. com; user=phone

Granularity Terminating Attestation Level Identification to terminating UA or CVT Current Values Verstat value STI-VS Description TN-Validation-Passed The number passed the validation TN-Validation-Failed The number failed the validation No-TN-Validation No number validation was performed

Granularity Possible Syntax Augmenting current verstat values with a “-A”, “-B” or “-the C” at the end Verstat value TN-Validation-Passed STI-VS Description The number passed the validation (kept to maintain backwards compatibility with early implementations which are expected to sign with Attestation A) TN-Validation-Passed-A The number passed the validation with Attestation A TN-Validation-Passed-B The number passed the validation with Attestation B TN-Validation-Passed-C The number passed the validation with Attestation C TN-Validation-Failed-A TN-Validation-Failed-B TN-Validation-Failed-C No-TN-Validation The number failed the validation (kept to maintain backwards compatibility with early implementations which are expected to sign with Attestation A) The number failed the validation for Attestation A The number failed the validation for Attestation B The number failed the validation for Attestation C No number validation was performed

Verstat for Anonymous CLIP/CLIR verstat should be signaled to the end user even in cases where Privacy is requested l For Caller initiated Privacy, common practice has the originating network/device signaling “Anonymous” in the From header. The P-Asserted-Identity (PAI) would carry the actual Calling Party number. l The originating network would perform SHAKEN Authentication over the PAI, sending the Identity header to the terminating network along with the PAI (with callers TN), From (anonymous) and Privacy headers l The terminating network performs verification (using the TN received in the PAI), and populates verstat into the PAI l Because of the Privacy indication, the terminating network removes the PAI header prior to sending the call to the UE: Example FROM: sip: anonymous; verstat=TN-Validation-Passed@anonymous. invalid

Next Steps l Agree on Best Practices with limited focused scopes l Priority and timeline for Best Practices