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3.1 Background

The Common Alerting Protocol (CAP) is a technical standard adopted by a consensus standards development body, the Organization for the Advancement of Structured Information Standards (OASIS). A CAP element may be thought of as corresponding to the name of a field on a form; a CAP value may be thought of as the information that is entered into the field. The CAP standard defines which elements must or may be included, and for some elements, defines a range of permitted values. For certain elements, it defines the format of the value.

The NWS has adopted CAP for a variety of uses, including HazCollect. However, since the NWS products are also designed to comply with international standards developed through the World Meteorological Organization (WMO), an NWEM is a specialized version of a CAP alert.

Process

In Chapter 1, the path of an NWEM through the HazCollect system was described. The corresponding steps in the process, with respect to message format, are described below.

  1. The message is composed in CAP compliant format using NWEM authoring software, and submitted by the user for relay to the HazCollect server.
  1. The NWEM authoring software validates the content of each field for compliance with CAP and NWS requirements.
    1. If the message is not valid, (e.g., required fields were left incomplete), the NWEM authoring software returns an error message to the user and prompts for correction.
  1. If valid, the message is routed to the HazCollect server through the DM-OPEN Web service.
  1. The HazCollect server validates:
    1. that the author's COG has been pre-authorized to access the HazCollect system, and if authorized, validates the geographic scope of the message against the geographic scope of the user's authority, (as previously described in Chapter 1); and,
    1. that all NWS required fields have been completed.
  1. If valid, the HazCollect server reformats the message for WMO compliance, and incorporates additional NWS supplied values.
  1. The NWS/WMO compliant message is distributed through the NWS dissemination systems, and EAS broadcast is requested.
  1. The user verifies that the NWEM was disseminated.
    1. The only way to verify whether the NWEM was actually issued is to monitor the NWS dissemination channels (e.g. NOAA Weather Radio or text products.) The only way to verify whether the message was broadcast via the EAS system is to monitor radio and television.
Please see the following links for further information on other CAP related initiatives . Then check your knowledge via the self-assessment quiz on the next page.
It's True! It's True! The Common Alerting Protocol is becoming a widely adopted international standard. In addition to implementation by the National Weather Service, CAP will become the standard for the next generation Emergency Alert System, the Integrated Public Alert and Warning System (IPAWS), and the Commercial Mobile Alert System (CMAS). For further information on the current status of these initiatives, see Net Links below.
Tip Tip Computer software can never evaluate whether the information contained in an NWEM is true, merits warning the public, or contains sufficiently complete and accurate information and instructions. This can only be ensured by human beings. The best practices described in Chapter 4, and the internal review process described in Chapter 5, and accompanying Job Aids, should help ensure your message content is valid.
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