iTechNote

The Schools Interoperability Framework Association (SIFA) is a non-profit membership organization whose members include over 300 software vendors, school districts, state departments of education and other organizations active in primary and secondary (pK-12) markets. These organizations have come together to create a set of rules and definitions which enable software programs from different companies to share information. This set of platform-independent, vendor-neutral rules and definitions is called the SIF Implementation Specification. The SIF Specification makes it possible for programs within a school or district to share data without any additional programming and without requiring each vendor to learn and support the intricacies of other vendors’ applications.

The Implementation Specification defines the software implementation guidelines for SIF; it does not make any assumption of what hardware and software products need to be used to develop SIF-certified applications. Instead, it defines the requirements of architecture, communication, software components, and interfaces between them.

Although there are many variations of SIF topographies, the common feature is that a number of applications wish to share data. All SIF implementations regardless of their complexity consist of one or more applications with their associated interface agents all being managed by a Zone Integration Server (ZIS). One typical use of SIF is to connect products from various vendors together within a single school. These applications could include a student information application, a food service program, and a library automation application. Each of these applications will have a vendor provided interface program called an “Agent” which typically is provided by the application vendor. Since the same school shares these applications, it makes sense to group them together into a logical entity. This entity is referred to as a “Zone” and is managed by a Zone Integration Server (ZIS). There are no predefined sizes for zones, so a zone can be as large or small as required in order to meet the needs of the customer. An application relies on its agent to exchange data using a predefined data model. Agents then communicate with other agents using the ZIS as a routing resource. The ZIS also provides access control so the customer can control which applications have access to which SIF data.

The data that can be exchanged in SIF is defined using a series of data objects. These objects are expressed using XML and comprise the schemas that define the semantics of information that can be managed by the applications. “StudentSchoolEnrollment,” “StudentPersonal” and “StaffPersonal” are three of the many predefined data objects.

When an application makes a change in one of the SIF objects, its agent will generate a SIF_Event message containing the changes that were made. The Zone Integration Server will receive this SIF_Event and propagate it to all the other agents that are interested in updates to that particular object. In order for an application to receive these SIF_Events, subscriptions for the SIF data objects of interest must be entered at the ZIS. The publish and subscribe model described here is used for event reporting. When an application (the “Requester”) wants to gather data from a specific data object, a SIF_Request message will be sent to ZIS. In most cases, the SIF_DestinationId element will not be placed in the request’s header which means that the application that will provide the response data (the “Responder”) will be chosen by the ZIS by looking up the “Provider” for the object being queried. In order to ensure scalability and reliability, SIF requires that its request/response and publish/subscribe models be asynchronous in nature.

The security model of SIF centers around three areas: encryption, authentication and access control. SIF provides application agents the ability to specify the encryption and authentication requirements for all other agents that eventually come into contact with their sensitive data. SIF HTTPS is the default communication protocol that all agents and ZIS implementations must support.

The full specification can be downloaded from SIF site. Microsoft has a SIF solution based on BizTalk Server and uses Windows 2000. It uses a SQL Server 2000 database to store the publisher/subscriber information and MSMQ as the queuing service. It also supports HTTP as the mechanism for communication between the agents. Edustructures is another vendor that provides SIF Compliant applications with its SIFWorks platform.