{
  "draft": "draft-worley-alert-info-fsm-10",
  "doc_id": "RFC8433",
  "title": "A Simpler Method for Resolving Alert-Info URNs",
  "authors": [
    "D. Worley"
  ],
  "format": [
    "TEXT",
    "HTML"
  ],
  "page_count": "45",
  "pub_status": "INFORMATIONAL",
  "status": "INFORMATIONAL",
  "source": "INDEPENDENT",
  "abstract": "The \"alert\" namespace of Uniform Resource Names (URNs) can be used in the Alert-Info header field of Session Initiation Protocol (SIP) requests and responses to inform a voice over IP (VoIP) telephone (user agent) of the characteristics of the call that the user agent has originated or terminated. The user agent must resolve the URNs into a signal; that is, it must select the best available signal to present to its user to indicate the characteristics of the call.\n\n RFC 7462 describes a non-normative algorithm for signal selection. This document describes a more efficient alternative algorithm: a user agent's designer can, based on the user agent's signals and their meanings, construct a finite state machine (FSM) to process the URNs to select a signal in a way that obeys the restrictions given in the definition of the \"alert\" URN namespace.",
  "pub_date": "August 2018",
  "keywords": [
    "Alert-Info",
    "audio signals",
    "call signaling",
    "call transfer",
    "resolution",
    "signaling",
    "signals",
    "SIP",
    "URN",
    "visual signals"
  ],
  "obsoletes": [],
  "obsoleted_by": [],
  "updates": [],
  "updated_by": [],
  "see_also": [],
  "doi": "10.17487/RFC8433",
  "errata_url": null
}