PROTOCOL TESTERS
Protocol implementations require more testing and verification
early in the development cycle

Selecting a protocol analyzer

BY JOE MENDOLIA
Computer Access Technology
Santa Clara, CA http://www.catc.com Four generations of protocol analyzers are still sold on the market today. When reviewing and selecting a protocol analyzer, designers should ensure that the product they are considering can provide all of the information they need to thoroughly debug their design, probe all of the communication interfaces necessary, and remain current for a minimum of 12 months from the date of purchase. Generations Originating as sophisticated software programs handled by an operating system's protocol stack, protocol analyzers have progressed through several evolutionary stages. Second-generation software-based systems gave way to fixed specification-based hardware designs. Test-set flexibility was introduced by using FPGA technology to allow uploading new operating systems–keeping the analyzer current in the face of changing requirements. This third-generation analyzer is still appropriate for testing a single communications protocol. However, a fourth-generation product, known as a universal protocol analyzer, is not only field upgradeable to the latest specification, but can transform itself into a different type of protocol analyzer with add-on modules and/or probes.

Protocol analyzers such as the PETracer ML offer nonintrusive high-speed data capture and analysis to speed design turnaround and time to market.

Choices A true protocol analyzer provides the ability to quickly identify complex sequences through the use of robust program interfaces. It is important to note that the protocol analyzer selected should provide a nonintrusive method of capturing the communications path under investigation. Other key features to look for include the following:

• Real-time triggering and filtering of information
• English language decoding of information for every level of the protocol
• User-extendable decoding capabilities for proprietary fields or unique layers
• Simple to use and easy to understand graphical user interfaces
• Ability to “scatter gather” information from one level of the protocol to the next to provide a logical view of the information
• Extensive searching capabilities that eliminate blind searches–this means that the analyzer should present items and conditions that actually exist within the recording
• Easy-to-navigate reporting systems that provide the ability to quickly identify areas of interest and allow the user to instantly view that area of the recording
• Ability to cross-trigger with other test equipment as well as importing and exporting information to other tools in real time.

Implementing the use of a protocol analyzer in the design development process can save not only time and energy for the design and test engineering team, but can be the difference between success and failure of the project. Today's return-on-investment depends on a product not only meeting a tight market window, but also requires that a product gain quick market acceptance with minimal returns.