Investigation into Alternative ITS Protocols for Center-to-Center Communications, 10-9274Printer Friendly Version
Inclusive Dates 11/01/01 - 09/30/02
Background - Eight years ago the Federal Highway Administration (FHWA), the U.S. Department of Transportation (USDOT), and the Joint Program Office (JPO) initiated a standards development effort. More than 100 different standards development efforts were initiated to provide a set of standards for the Intelligent Transportation Systems (ITS) industry. The standards are broadly termed the ITS National Standards and cover a wide range of application domains (e.g., sign control, information exchange) within the ITS industry. The standards development process differs from the traditional method of standards development in the software industry - that widely accepted, widely used applications become the standards (e.g., HTML). During the last ten years, the ITS industry has developed a number of systems that were not designed to interact. Each of these systems has been typically developed as an island and cannot communicate with any other system. A major component of the ITS National Standards is the development of protocols to allow standalone transportation centers to exchange data in a seamless and efficient fashion. The FHWA has mandated that all future ITS deployments be based on the ITS National Standards.
One of the most significant standardization efforts is the area of Center-to-Center (C2C) communications. As a committee member on the two committees developing the appropriate standards, SwRI has been active in understanding and defining the C2C technologies. Throughout the United States, five significant programs have been funded to interconnect ITS centers. One of these is in Texas, and SwRI has been funded $1.9 million to date to develop an infrastructure to allow centers to exchange data throughout the State of Texas.
The Texas project uses an ITS standard protocol known as DATEX/ASN (ISO standard) to support the information exchange. The Texas project is also unique in that it is the only C2C system that connects systems built on different software bases (i.e., heterogeneous software systems). Other significant deployments in the United States require each center to execute the same base software. The DATEX/ASN protocol has not received widespread acceptance and will more than likely become unused in the near future. The rapidly evolving XML (Extensible Markup Language) protocol is a candidate protocol to replace DATEX/ASN. Although some effort has been made in the ITS standards community to establish CORBA as a base protocol, many in the field believe XML will supplant DATEX/ASN and CORBA within the next five years.
This program was undertaken to determine if either CORBA or XML is appropriate to implement the real-time requirements of C2C applications. The program explored the use of these alternative protocols, and a prototype was developed that successfully demonstrated that CORBA and XML could be utilized as the transport protocol for C2C communications.
Approach - The original proposal defined five tasks to be performed. The following lists the project tasks and results of each task:
Task 1: Requirements Analysis
Tasks 2, 3 and 4: CORBA Investigation, XML Investigation, Demonstration (task status combined for the purposes of status reporting because the efforts were intertwined)
All these objectives were fulfilled on schedule and within budget. With respect to success criteria, at the time that the IR&D proposal was submitted, it was stated that the success of the project would be determined if SwRI could architect a solution that facilitated the exchange of information between environments that are built utilizing different protocols. The project very successfully demonstrated this exchange of information across multiple protocols. In fact, the effort was so successful that the Texas Department of Transportation (TxDOT) is funding SwRI under the Statewide Integrator program (10-05713) to implement an XML/SOAP solution in the next generation of the TxDOT Center-to-Center (C2C) program (task value is $1.2 million).
Additionally, SwRI and TxDOT will be considered the front-runner in developing the next generation of C2C low-level protocol standards. SwRI will be submitting the results of the XML/SOAP development efforts to the NTCIP Joint Committee for their consideration in funding a work item to develop a new ITS standard.