Common Alerting Protocol

From ArticleWorld

The Common Alerting Protocol, or CAP, was created in its present form in April 2004. This was in response to the National Science and Technology Council’s November 2000 report on “Effective Disaster Warnings,” which recommended the creation of a standardized disaster alert system to allow the instantaneous sharing of warning data across geographical and technological boundaries. A group of emergency management professionals initiated the project in 2001. The National Science and Technology Council report was used to frame the initial organizational structure of the CAP system.


Many organizations, both for- and non-profit, rose in support of the new system. After many area studies and lengthy demonstrations of the effectiveness of CAP, the final model was released to the Organization for the Advancement of Structured Information Standards (OASIS) for approval. OASIS, an international group that sets standards for e-business and related technologies, approved the CAP model 1.0 in 2004. It was later revised as CAP 1.1 in October of 2005, under further recommendations from OASIS.


The CAP currently allows data on emergencies and public warnings to be instantly distributed to various communities using different media technologies. CAP uses an XML format, which permits it to be used by most emergency broadcast systems. This allows warnings to be sent out more quickly to the public.

CAP also gathers data on specific warnings, which can be used to create a model of alert and threat patterns in a specified geographic area. This model can be used to detect a greater threat (such as a large-scale environmental disaster or terrorist act) by comparing nearby emergency alerts to each other and drawing a cohesive picture of the activity they represent.

The CAP format is compatible with earlier technologies, such as the Specific Area Message Encoding protocol used on the radio, and the Emergency Alert System used on television. It also has many other capabilities. Alert messages can be sent in multiple languages, at various scheduled times. Three-dimensional maps allow information to be targeted to the right community. Warnings are easy to update and cancel, and there are support systems to allow the easy creation of concise, informative, and useful warning messages. The system also has many digital capabilities not seen in earlier warning models, including digital video, audio and image capabilities and digital encryption.

Current Usage

It is used in the United States by a multitude of organizations, including the Department of Homeland Security, the Geological Survey, National Weather Service, California Office of Emergency Services, and the Virginia Department of Transportation. It is also used by many corporations, including Oregon RAINS, E Team, MyStateUSA, Blue292, Warning Systems, mobilFoundations, Comlabs, Ship Analytics, IEM, Hormann America and GeoDecisions. In 2005 the Department of Homeland Security demonstrated the efficacy of the system by conducting digital Emergency Alert System broadcasts on digital and public television. These broadcasts were beamed across the country using the CAP system. The Department of Homeland security is currently using CAP to develop an advanced Tsunami warning system, as well as a universal alert protocol that will be able to send alerts about all dangers, in all media outlets across the country.