1. Proposed ATIS Standard for Signing of SIP RPH
February 20, 2017
ATIS PTSC
Proposed ATIS Standard for Signing of SIP RPH
Ray P. Singh
formerly Applied Communication Sciences

2. Outline Overview: Problem Statement Solution Objective and Proposal
Proposed IETF STIR Extension
Proposed ATIS Standard Using IETF STIR Extension
Contribution List

3. Problem Statement Overview
RFC 4412 defines the following namespaces for the SIP “resource-priority” header field (RPH): “DSN,” “DRSN, ” “Q735,” “ETS” and “WPS”
The RPH namespace parameters could be spoofed or inserted by unauthorized entities
Telephone service providers will drop RPH received from un-trusted networks
Lack of means to verify authenticity of received RPH means service providers cannot act with confidence impacting NS/EP Priority Services supported using the “ETS” and “WPS” namespaces

4. Solution Objective and Proposal
Define a mechanism leveraging SHAKEN to validate information populated in the namespace parameters in the SIP “resource-priority” header field (e.g., “ETS” and “WPS”) in support of NS/EP NGN-PS
Solution Proposal
IETF
Define STIR PASSPorT extension to sign the RPH namespace parameters:
ATIS
Specify ATIS standard using STIR PASSPort extension for support of NS/EP Priority Services

5. Proposed [draft-ietf-stir-passport] extension:
Define extension to sign the RPH namespace parameters:
PASSPorT Claim
PPT: “rph”
“rph” claim
Object “namespace”
Values: “DSN,” “DRSN, ” “Q735,” “ETS” and “WPS”

6. ATIS Standard Specify ATIS standard for NS/EP Priority Services
Use of PASSPort “rph” claim for “ETS” and “WPS” namespaces
Define NS/EP attestations
Attestation
A. Full NS/EP Attestation
The signing provider shall satisfy all of the following conditions:
Is responsible for the NS/EP (ETS or WPS) authentication and authorization of the call/session
Is responsible for populating the “ETS” or “WPS” namespace in the SIP RPH
B. Partial NS/EP Attestation
The signing provider shall satisfy all of the following condition:
Is responsible for populating the “ETS” or “WPS” namespace in the SIP RPH.

7. Contribution List
PTSC : Proposed New ATIS Issue for RPH Signing
PTSC : Draft Standard on Signature-based Handling of SIP RPH Assertion using Tokens
PTSC : Proposed [draft-tbd-stir-rph-01] for PASSporT extension

8. TRANSFORMATIVE RESEARCH