Configuration Management for Transportation Management Systems:
Configuration Management (CM) describes a series of processes and procedures developed in the information technology community to establish and maintain system integrity. It is an integral part of the systems engineering process. While some of the terms used in CM may be unfamiliar to transportation professionals, the core concepts and practices of CM are not technically complex. Rather, they represent sound practices in developing and maintaining any system. As you will see in this document, CM makes sense for use in transportation management systems (TMSs).
The purpose of this primer is to identify for a non-technical audience the key aspects, identify issues for their agencies to consider, identify the benefits or value, profile successful practices, describe why and identify opportunities how agencies may benefit from and why they should consider or using various configuration management procedures, techniques, tools, or requirements into their policies, programs, and day-to-day activities.
There are two fundamental purposes of CM – to establish system integrity and to maintain system integrity. To an individual who designs, develops, operates, or maintains complex transportation management systems, the definition of integrity is well understood:
The importance of CM in establishing and maintaining a functionally sound TMS cannot be overstated. However, CM can consume significant amounts of resources including staff time and money. For this reason, developing a CM program that fits the needs of a particular system is vital to its success. In other words, CM programs are not one-size-fits-all entities. Some may think that CM is too large an undertaking to be worth it for his or her system or that the agency cannot possibly implement such a program. Although CM, and its complexity, can and should grow as a system grows, it does not need to include each and every item described in this document.
As TMSs are becoming more sophisticated through the addition of new subsystems, integration with other systems, and overall physical expansion, the need to control the rapid pace of change has become apparent. One problem that has been discovered as these systems change is that groups within an agency often work independently of each other, conducting changes without consulting one another and documenting the changes improperly. If the entire system is to undergo a major change or upgrade, this can present a significant problem. Contractors or agency personnel often will have to devote significant effort to retracing the steps taken for minor changes to the system to understand the current status. Doing so obviously requires major outlays of time and money.
A proper CM program will ensure that documentation (requirements, design, test, and acceptance documentation) for items is accurate and consistent with the actual physical design of the item. In many cases, without CM, the documentation exists but is not consistent with the item itself. For this reason, contractors and agency staff will frequently be forced to develop documentation reflecting the actual status of the item before they can proceed with a change. This "reverse-engineering" process is wasteful in terms of human and other resources and can be minimized or eliminated using CM.
Some of the other benefits of CM, which hopefully will never be needed, are its provisions for disaster recovery. Because a CM program should ensure that an accurate, up-to-date baseline of the system exists, the re-engineering process should be far less costly. Without CM and the associated baselining process, entire subsystems would require redesign at a much higher cost, and the recovery process would be greatly lengthened, if even feasible.
CM also provides for administration of change decisions with a system-wide perspective in mind. The configuration control board (CCB) has personnel with various areas of focus and from various departments within an agency. All proposed changes to the system are considered by the CCB in terms of the system, not just particular subsystems. Using tracking tools, unapproved changes can be detected and fixed more easily.
In cases of subsystem or system development, CM allows TMS management to track requirements throughout the life cycle through acceptance and operations and maintenance. As changes are inevitably made to the requirements and design, they must be approved and documented, creating an accurate record of the status of the system. The CM process may be (and ideally should be) applied throughout the system life cycle. Over time, CM will reduce operating and maintenance costs, while improving system performance and reliability.