Architectures can be broken down into macro and micro levels. At the macro level, enterprise architectures provide a big picture view and encourage holistic under- standing of various parts that make up the architecture. They manage the complexity of the enterprise and align business strategies with implementations. At the micro level, system architectures define the form and function of a system by defining discrete, non-overlapping parts or components. The E-Safety Network provides the enterprise architecture for interoperable emergency data communications that includes the EPAD system.
E-Safety.Network
The E-Safety Network is a unified emergency Web services information architecture that ties together the various application systems used by law enforcement, fire, emergency medical, public health, transportation, emergency management, and homeland security agencies, among others (COMCARE, October, 2004). It treats the entire emergency response community as one extended enterprise, providing a framework within which each entity can operate. It is open, platform-neutral, and standards-based to enable flexible interoperability across organizations, technology platforms, and implementation methods.
There are five architectural layers (Figure 1) that must be in place to achieve effective data interoperability. These layers include data transport, data standards, shared facilitation services, individual agency applications, and the policies and protocols that govern the use of the system when data interoperability is achieved.
The transport layer represents the networks used for communications. This layer manages the end-to-end delivery of messages and determines how data are transferred between network devices. It manages user sessions and dialogues and controls the establishment and termination of logic links between users. The E-Safety Network requires reliable and secure broadband data connections using Internet protocols.
Figure 1. E-Safety Network: Five architectural layers
Data standards create a common language that enables data sharing among indi- vidual agency application systems. The Department of Homeland Security Disaster Management eGov Initiative has launched a program to facilitate standards develop- ment by bringing together leaders from all professions needing to share data during emergency response operations. These practitioners develop and field test common sets of emergency message standards. Over the last year, this and related projects have resulted in many eXtensible Markup Language (XML) standards such as the common alerting protocol5 (CAP), the Vehicular Emergency Data Set6 (VEDS), and the Emergency Data Exchange Language7 (EDXL) suite of standards (XML, 2005).
These non-proprietary XML message formats use simple object access protocol (SOAP) “packaging” for both specialized and general emergency data exchange.
For content, they draw on the dictionary and data model work of other efforts such as the Global Justice XML Data Model (OJP, 2005) and the new DHS National Information Exchange Model (NIEM) (NIEM, 2005).
Facilitation services are common shared tools, services, and resources offered through a collective effort of the emergency response community. They enable interoperability and are available for use by authorized emergency entities. These services include, but are not limited to, security, diagnostics, routing directory, iden- tity management, access control, digital rights management, and authentication. By using these shared facilitation services, agencies do not have to spend their limited funds creating and maintaining these functions on their own. EPAD as a routing directory is one of these services.
The fourth layer represents the wide array of agency applications used for emergency preparedness, response, and recovery. These systems include complex computer- aided dispatch systems (CAD), Web-based emergency management tools, local and statewide geographic information systems (GIS), hospital capacity reporting systems, and other innovative applications for data collection, analysis, and presentation.
Agencies are encouraged to purchase systems that best meet their needs. However, in order to operate within the E-Safety Network, these applications must be able to send and receive XML messages to and from other applications in standardized formats. It should not matter to a 9-1-1 CAD system that it is receiving data from an emergency management tool about a flood, a telematics message from OnStar, a bio-terrorism alert from the Center for Disease Control (CDC), or data from a wireless or Voice over Internet protocol (VoIP) call. The same standardized data interface should be used.
Lastly, the E-Safety Network is not complete without the policies and protocols that determine rules for operating within it. Does a hospital have the same privileges as the county Department of Transportation (DOT), the 9-1-1 center, the police, or the towing company? Who has access to what data and who is allowed to send what messages? Some of these policies are already in place today. For instance, a 9-1-1 center is required to alert certain agencies when there is a hazardous materials (HAZMAT). A fire chief becomes the incident commander if there is an explosion,
and then sets up an Incident Command System (ICS) with required sections and reports. Emergency Medical Services (EMS) may only administer certain kinds of treatment to patients in ambulances. Only the secretary of DHS or his designee can change the alert level, or communicate it. Only the president or his designee can activate the Emergency Alerting System. These are only a few examples of the types of policies and protocols needed for data interoperability. Many more still need to be developed before this type of architecture is deployed.