Trends in Technology: EAS Update

January 1, 2011


As you are aware, the Federal Emergency Management Agency (FEMA) published the technical standards and requirements for CAP-formatted EAS alerts on Sept. 30, 2010, thus triggering the 180-day window for compliance among broadcast stations. Fortunately, for those of us directly involved in the implementation of the new equipment, the FCC waived part 11.56 of its own rules on Nov. 23, and moved the deadline for implementation back to Sept. 30, 2011. In paragraph 10 of its order 10-191, the FCC wrote "It is in the public interest to provide EAS participants with enough time to correctly and efficiently implement the requirements for a next-generation EAS. We are concerned that retaining the 180-day deadline would lead to an unduly rushed, expensive, and likely incomplete process." The agency goes on to say that while it does not anticipate any further waivers, it reserves the right to extend the deadline yet again.

That being said, it is important to note that progress is being made in working out the details of the implementation of CAP, and that the deadline will be here before long. CAP is coming sooner than later, and you should endeavor to learn about it. I'll discuss some of the remaining issues with the implementation of CAP and how they are being addressed.

For starters, let's decode some of the many acronyms that you'll see. CAP stands for Common Alerting Protocol, and version 1.2 of CAP was developed by OASIS (Organization for the Advancement of Structured Information Standards). CAP is the digital messaging format to be used in the implementation of IPAWS (Integrated Public Alert Warning System), which is our nation's next-generation emergency warning and alert system. The most important aspects of IPAWS are as follows:

  • It is a comprehensive system that enables the proper authorities (such as federal, state, territorial, local and tribal associations) to alert and warn the citizenry under any emergency conditions and by way of as many means as possible.
  • It will allow the president to speak to the American people during any emergency situation.
  • By making use of standards such as CAP, it will create an interoperability framework that will allow a single warning message to be transmitted over different systems.
  • It will enable alerts and warnings to those with disabilities and those without an understanding of the English language.

    While we all know radio and TV are an important means by which much of the populace can be reached, we also know there are many new means -- such as the Internet and more specifically mobile devices -- that allow an even greater percentage of the public to be reached rapidly should that need arise. IPAWS is the result of an initiative taken by FEMA for just that purpose -- the integration of multiple methods of reaching the public by disparate means.

    -- continued on page 2



  • So just how will it work? IPAWS will accept standards-based (CAP) alert and warning messages from emergency managers using existing state, local, territorial or tribal systems, or by way of an IPAWS Web interface. These messages will be forwarded to the IPAWS aggregator, which will in turn disseminate the messages via IPAWS OPEN (Open Platform for Emergency Networks). The entities (like 14,000 radio stations and 10,000 cable TV systems in the United States) providing that last mile reach to the public will retrieve pertinent emergency messages (formatted in CAP) from IPAWS OPEN by means of IP networks such as the public Internet. I should also note that the methods of receiving EAS tests that we've been using for years now will continue to exist; messages received from IPAWS OPEN will supplement them.

    It wasn't clear when I composed my last article about CAP as to whether or not messages from IPAWS OPEN would be retrieved (pulled) or sent (pushed). According to one industry source I spoke with, it has been resolved that messages will be pulled. This makes a lot of sense from the aspect of network security; it is much more simple to configure a device to originate communication from the LAN side of a firewall or router than it is to configure that same router or firewall to allow unsolicited messages to come in from the public Internet to reach a host on the LAN. This of course also allows the owner of the CAP-enable device at the radio station to decide how frequently updates will be requested, and so forth. According to this same source, IPAWS OPEN will operate like any other large server, from a large (or many large) data centers and it will be the responsibility of FEMA to build a system large enough to handle the tens of thousands of CAP-enabled devices that will be querying it on a regular basis.

    Take off your CAP

    So now that you know something about IPAWS, let's take a closer look at CAP. Here are some of its most important aspects:

    CAP is a simple, general format for exchanging all hazard emergency alerts and public warnings over all kinds of networks. It features the following:

  • Geographic targeting using latitude and longitude shapes and other geo-spatial representations in three dimensions
  • Multilingual and multi-audience messaging
  • Phased and delayed effective times and expirations
  • Updates and cancellations
  • Templates for the creation of warning messages
  • Digital signature capability
  • Facilities for audio and images

    In the course of researching this article I read the "Working Group 5A CAP Introduction Final Report" from CSRIC (Communications Security Reliability and Interoperability Council) and found there is more to the story regarding CAP and EAS.

    -- continued on page 3



  • According to CSRIC: "Adherence to the CAP standard alone does not guarantee that connected systems and equipment will be conformant with Part 11 Rules for EAS activation and display." CAP is a basic container for alert data, and practitioners have increasingly found that additional specificity has been required for the appropriate usage of CAP in various systems, including EAS. To resolve this issue, FEMA issued an IPAWS CAP profile, which describes how to create EAS messages specifically for the IPAWS system. Broadcast equipment manufacturers, as represented by ECIG (EAS-CAP Industry Group) have offered further specificity on how CAP-formatted messages can be used to generate part 11-compliant EAS messages. The IPAWS CAP profile was developed by integrating the requirements related to three federal warning-delivery systems: The broadcast EAS as recommended by the ECIG, the NOAA non-weather emergency message (NWEM), and CMAS for cellular telephones.

    Again, referring to the CSRIC document: In May 2010, the ECIG published guidelines "intended to further reduce the areas of uncertainty in how an alert will be presented to the public via CAP/EAS so that originators and distributors of alerts can deliver the intended message to the public, regardless of the vendors or platforms involved." The CSRIC document was published in September 2010, and even at that time, there was still some room for interpretation of CAP messages. From the same document: "Public warnings intended for transmission over EAS can be encoded in CAP messages in various ways. As both CAP v1.2 and CAPv1.2 IPAWS Profile (v1.0) make use of several free-form text elements and several optional elements, there is ample opportunity for a CAP message rendered by one CAP-to-EAS device to differ when rendered by another vendor's device. There can also be a difference between what the originator intended for an alert, and what the alerts contain, when broadcast by CAP/EAS devices."

    It is clear there are still issues to be resolved prior to the real implementation of CAP at the end of September 2011. However, according to the same industry source I referred to earlier, the issues are being resolved, and indeed most if not all will be resolved by the end of March of 2011. Manufacturers are working in earnest with FEMA so the new deadline can be met. Broadcasters should plan for capital purchases this year so they can implement CAP/EAS by the deadline.


    Irwin is transmission systems supervisor for Clear Channel NYC and chief engineer of WKTU, New York. Contact him at doug@dougirwin.net.



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