Dial String Parameter for the Session Initiation Protocol Uniform Resource Identifier

Dial String Parameter for the Session Initiation Protocol Uniform Resource Identifier NeuStar RFC 3966 explicitly states that 'tel' URIs may not represent a dial string. That leaves no way specify a dial string in a standardized way. Great confusion exists with the SIP URI parameter "user=phone", and specifically, if it can represent a dial string. This memo creates a new value for the user parameter "dialstring", so that one may specify "user=dialstring" to encode a dial string as a 'sip:' or 'sips:' URI. [STANDARDS-TRACK]