A Very Short Introduction to the Common Alerting Protocol
(This is posted temporarily until more content can be added. This piece was written for the ComCare Alliance)
By DAVID COURSEY
Co-Founder & CEO
National Warning Corporation
The Common Alerting Protocol is the most important advance in public warning in a generation. A single message, created using CAP, can now do tasks that until now required many individual messages. CAP was also created with location-aware devices in mind, allowing CAP messages to properly warn only devices that are actually inside the warning area.
CAP is the federally-endorsed standard for emergency warning messages and all outlets for the Emergency Alert System will soon be required to accept CAP-formatted activation messages. CAP messages will soon be converted from text into speech and transmitted over NOAA Weather Radio, giving local emergency managers an important new warning tool.
And—remember—we are talking about a single warning message doing all this work. But wait, as they say on TV, there’s more.
CAP messages can activate sirens, strobe lights, and will soon talk to highway signs. CAP is proposed as the FCC standard for sending warnings to cellular handsets. Given proper interface software, CAP messages can be received and acted upon by almost any device.
As I said, CAP is the most important advance in public warning in a generation, maybe the most significant advance ever.
What Is CAP?
CAP is an implementation of XML, the Extensible Markup Language. Markup languages are used to encapsulate information in a description of the information itself. The best-known markup language is HTML, the Hypertext Markup Language, used to create Web pages.
Here’s a generic example of a markup language: <address>123 Main Street</address>. In that example the address itself is surrounded by tags that tell us where the address starts and stops. That allows the information in a message to be separated from how the information is presented. While humans can usually look at a page and pick out the address, computers need clues to do that and HTML provides them.
CAP is a collection of 43 tags used to describe the information that might be included in a warning message. Not all messages include all 43 elements, and some are purely optional.
CAP introduces a universal method of describing any type of emergency as to its type, urgency, severity, and certainty of occurrence. Text descriptions may be added. Locations may be described in a variety of ways, although CAP prefers the sets of latitude/longitude coordinates necessary for warning GPS-enabled devices.
Messages may include user-created information, may be encrypted, and may also include attachments, such as maps, images, or audio files.
Fortunately, the complexity of CAP messages can be hidden from human users. National Warning Corporation and others have created specialized software allowing emergency managers to easily create and distribute CAP messages. The software implements the concept of “write one, use everywhere” that allows the same CAP message to be used by multiple devices.
For example, a message created in our WarningWizard™ software might activate the Emergency Alert System, be transmitted as voice on NOAA Weather Radio, activate sirens and tone-alert in (only) the effected area, alert first responders’ pagers, and instruct a “reverse 911” system which residents need to be called.
That’s a tremendous amount of work for a single message to do and it will translate into dramatically-improved warning capabilities, not just in the U.S. but globally. CAP is already a standard accepted by OASIS, the XXX. It is also expected to be adopted by the U.N.-sponsored International Telecommunications Union as the worldwide standard for public warning messages.
If you are involved with emergency warnings, you should be involved with the Common Alerting Protocol. If we can help you in any way, it would be our pleasure.
