To understand the ingredients of network time synchronization, it is first necessary to understand why synchronization is important. In other words, what are the needs of the organization that network time synchronization fulfills? Once you know which needs apply to your particular situation you can better assess your technical requirements.
In general, network time synchronization fulfills two missions: 1) It allows events to occur at the proper time (i.e., event synchronization); and 2) It provides proof when events occurred or did not occur (i.e., computer forensics). The first mission occurs during the fact; the second mission occurs after the fact. The table below summarizes some typical examples.
Organizations employ event synchronization to accomplish one or both of the following objectives: 1) To schedule a process—i.e., to ensure that it starts or stops on time or runs for a specified period regardless of when it starts or stops; and 2) To ensure that cooperating processes can interoperate correctly—so that if one process hands a task off to another process, the second process will in fact be ready to accept the handoff.
Examples of both scenarios occur frequently in industries like pharmaceuticals where a batch of materials, let’s say, is supposed to be heated to a certain temperature for a certain period of time and then passed to another process for mixing. If the timing of these events is not exact, the batch may be ruined. Furthermore, if one process begins before another has finished, then the actual production equipment—not to mention the product itself—could be damaged. Similar scenarios happen all the time in industries like manufacturing, logistics, and electric power.
In the power industry, generators thousands of miles apart must constantly stay in phase at 60 cycles per second. If generators operate at different points in the phase cycle, they will actually work against each other—not only reducing power output but also potentially destroying the generators themselves. In addition, there are literally millions of electric clocks around the world that use the 60 Hz cycle (or 50 Hz, depending on which country you are in) to maintain the correct time. During periods of high load this cycle tends to slow down and, alternatively, to speed up during periods of light load. Utilities in turn rely on accurate network time synchronization to ensure that they do in fact provide the correct phase cycle their customers expect.
Financial services and high-frequency trading are good examples. Take the networks over which traders buy and sell securities. These networks must execute trades within a very small, and also extremely accurate, window of time (three seconds, in the case of NASD). The reason for this accuracy is obvious: prices change rapidly in financial markets and traders want to make sure that deals happen when the posted prices are still in effect.
They also want to know (and regulators want to know as well) a particular trader’s holdings in an investment at a particular point in time. So not only must trades actually occur on schedule, they must be accurately time stamped to reflect that they were traded at a specific time.
Timestamps on financial documents are a time-honored way of proving that money changed hands, documents were signed, letters were posted, and other business events occurred when they were alleged to have taken place. In the digital realm, this type of after-the-fact time lining is called computer forensics—the second category of network time synchronization applications.
Computer forensics has received considerable publicity lately—much of it due to high-profile Wall Street indictments. Many of these were made possible because of paper trails established in part through the use of timestamps on email and other electronic documents. Recent legislation such as Sarbanes Oxley and HIPPA (Health Insurance Portability and Accountability Act) mandate how organizations maintain records. With respect to digital documents, they expressly require the use of verifiable timestamps to prove the state and control of documents at particular points—like when they were created or subsequently altered and by whom. Officers in companies covered by these laws risk jail time and heavy fines if theirorganizations do not comply.
Timestamps, of course, are valuable evidence even apart from criminal investigations. Organizations have a business need to trace the chain of events that led to key events, such as an important decision or an action by an employee. Additionally, there are a host of technical reasons companies employ timestamps. Diagnosing a computer problem, for example, often means going back over log files to trace back the series of events that led up to a fault. Without demonstrably accurate timestamps, it is hard to see whether an issue was the cause or the consequence of some other issue.
Again, the electric power industry provides a good example. As previously mentioned, operators have to phase synchronize generators running hundreds of miles apart. In addition, they also must monitor the power grid for events such as voltage spikes or equipment outages using systems known as SCADA (supervisory control and data acquisition). SCADA systems are heavy users of time synchronization technology—specifically GPS time servers—and timestamps are a major reason why. Timestamps from these servers provide the critical evidence needed to identify the causes of power failures, such as the one that crippled the Northeastern US and Ontario in August 2003. As such backtracking events to the power blackout’s root causes took weeks and could have been accomplished much faster had timestamps been more accurate and more widely distributed throughout the grid. Such timestamps did not exist, so investigators often had to cross check one timestamp against another in order to recreate the actual time index over which events took place.
In pharmaceuticals, the issue of time stamping is a regulatory imperative under FDA regulation 21 CFR Part 11 and others. Companies have to not only synchronize production steps according to strict recipes; they have to also document the fact that these precisely synchronized actions did in fact happen as scheduled. Without accurate and pervasive time stamping, pharmaceutical companies risk severe penalties plus the possibility they have the ability to trace back a problem if something did in fact go wrong during the manufacture of one of their products.
Microsemi provides synchronization services that assist customers with the planning, deployment and maintenance of synchronization infrastructure. Services are designed to lower costs, streamline processes, ensure quality, and deliver the highest level of performance from your synchronization network. Visit Timing & Synchronization Systems and learn how we can help provide you with comprehensive solutions across a wide range of applications.
In my upcoming articles, I’ll write about the 5 essential elements of network time synchronization. Please also read my previous article, “5 Essentials of Network Time Synchronization.”
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