P-Access-Network-Info ABNF Update

defines the Session Initiation Protocol (SIP) P-Access-Network-Info header field. The header field syntax contains an 'access-info' header field parameter, with a set of pre-defined values. Most pre-defined values follow the 'generic-param' rule . However, currently the Augmented Backus-Naur Form (ABNF) requires new values are required to follow the 'gen-value' rule , which is more restrictive than 'generic-param'. There is no justification for the restriction, and new values have already been defined following the 'generic-param' rule. This document updates section 5.4 of , by modifying the extension-access-info part of the P-Access-Network-Info header field ABNF. As the P-Access-Network-Info header field is mainly used in networks defined by the 3rd-Generation Partnership Project (3GPP), where new values following the 'generic-param' rule have been followed, the update is 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 .

This section updates the ABNF defined in section 5.4 of RFC 7315, as described below:

The security considerations for the P-Access-Network-Info header field are defined in . The ABNF 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]