P-Access-Network-Info in SIP ACK requests

The 3rd-Generation Partnership Project (3GPP) has identified cases where different Session Initiation Protocol (SIP) private header extensions referred to as P- header fields, defined in RFC 7315 , need to be included in SIP requests and responses currently not allowed according to RFC 7315. This document updates RFC 7315, in order to allow inclusion of the affected P- header fields in such requests and responses. In order to get a complete picture, this document also contains a set of errata that are to be filed against RFC 7315, in order to fix misalignments that occurred when RFC 3455 was updated and obsoleted by RFC 7315. This document updates RFC 7315 , by allowing the insertion of the P-Access-Network-Info header field in SIP ACK requests. As the P- header fields are mainly used in (and in most cases, only defined for) networks defined by the 3rd-Generation Partnership Project (3GPP), where the updates defined in this document are already defined , the updates are not seen to cause backward compatibility concerns.

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in .

RFC 7315 contains contradicting statements regarding the usage of SIP P- header fields in SIP requests and responses, which leave the presence of the SIP P- header fields in the SIP requests and responses open to interpretation, and different implementations. Statements in section 5.7 are not aligned with the definitions and usage of the SIP P- header fields specified in section 4. This section defines the errata that is to be submitted against RFC 7315. The scope of the errata is only alignment between RFC 3455 and RFC 7315. NOTE: In the case of the P-Called-Party-ID header field, allowing it in PUBLISH requests was deliberately done in RFC 7315. It will therefore not be impacted by the errata.

The errata makes the following changes: P-Associated-URI: Remove statement that the header field can appear in the SIP REGISTER method. P-Called-Party-ID: Delete statement that the header field can appear in SIP responses. Add statement that the P-Called-Party-ID header field can appear in the SIP REFER method. P-Visited-Network-ID: Delete statement that the header field can appear in SIP responses. Add statement that the P-Visited-Network-ID header field cannot appear in the SIP NOTIFY, PRACK, INFO and UPDATE methods. P-Access-Network-Info: Add statement that header field can appear in SIP responses. P-Charging-Vector: Add statement that the header field can appear in SIP responses. Add statement that the header field can not appear in the SIP ACK method. P-Charging-Function-Addresses: Add statement that the P-Charging-Function-Addresses header field can appear in SIP responses.

This section updates section 5.7 of RFC 7315. Note that the old text incorporates the fixes done by the errata described above. The following updates are done: P-Access-Network-Info: Add statement that the header field can appear in the SIP ACK method. P-Charging-Vector: Add statement that the header field can appear in the SIP ACK method.

The security considerations for the P-Access-Network-Info header field are defined in . The update defined in this document does not impact the security considerations.

This document makes no requests from IANA.

TBD

[RFC EDITOR NOTE: Please remove this section when publishing] Changes from draft-holmberg-dispatch-rfc7315-updates-00 - Add text when version -01 is submitted.