So the NTP protocol has been refined by including additional timestamps for when the packets are sent and received at each end. It also assumes the server is able to turn around the response instantaneously, which is clearly not all that accurate. This assumes the path to the server is the same as the path from the server, which is usually a fairly reasonable assumption in most modern networks. You can make a pretty good guess at how long it takes for that packet to get to you by sending the server a packet and making careful note of how long it takes to get the response. If I send you a packet saying to set your clock to 12:00, you need to know very accurately how long it took for that packet to reach you. Why syncing clocks is hardĪccurate clock synchronization presents several interesting problems. And there are other industrial applications where even more accuracy is required. This is just within the reach of NTPv4, but not previous versions. If you want to match the phase to within 1%, you need the clocks synchronized to 170 microseconds. In this environment, unsynchronized clocks could result in fires or damaged equipment.Īt 60Hz, one full cycle is about 17ms. So losing a lot of power means possibly creating a lot of heat. If the phase isn’t matched, power is lost. Power grids, in particular, need extraordinary accuracy for ensuring the phases of the 60Hz (or 50Hz in many locations) AC currents are correctly matched. This includes things like industrial and financial (stock trading) applications. ![]() People tend to use PTP for applications where a microsecond is a long time. It is, however, more complicated to deploy and not universally available on network equipment.įor most applications, NTP is sufficient. This protocol is able to synchronize clocks to sub-microsecond accuracy. The other common network clocking protocol is called Precision Time Protocol (PTP), or IEEE 1588. (I’ll explain what that means in a moment.) NTP is accurate to about 1ms, although you can get sub-millisecond accuracy with NTPv4 if you design the network carefully and have access to your own Stratum 1 clocks. It’s a mature protocol that’s been around for decades and is currently in its fourth version. The one we normally use is Network Time Protocol (NTP). The second way is to use an automatic time synchronization protocol. And it’s incredibly time consuming to log into all of those devices and manually set the clocks. Then you’ll need to do it again tomorrow. The clock in every device will slip a little bit, probably in random directions, so there could be a difference of several seconds between the fastest and the slowest clocks by the end of the day. The first is to do it manually by logging into every network device and manually setting the clocks against some common source, like your watch. There are really two ways to synchronize clocks for network optimization. How to synchronize clocks on network devices No time keeping device is truly accurate, so without proper synchronization, the natural drift of between devices internal time-keeping will ultimately lead to issues. Time synchronization is also something that needs to be constantly maintained. Depending on your industry, such as healthcare, some legal regulations require accurate timestamps on all logs. Log file accuracy, auditing & monitoringĪccurate time may also be a legal requirement.When events happen, the order in which they happen, and how that data is then collected and logged depends almost entirely on devices being in synchronization.Īccording time synchronization device manufacturer Symmetricom, key areas where time synchronization directly effects network operations are: Time, more importantly, accurate time shared by all devices, is vital for network communications to be successful. The other important reason to synchronize the clocks on your network devices is so they can in turn provide time services to other devices at the same site. And, related to this, are you seeing the similar problems at around the same time every day? More generally, you want to know if the similar log messages you’re seeing are related to the same incident or if maybe some of them happened much earlier or later. If your clocks aren’t synchronized, it becomes much more difficult to correlate log messages between devices. This automatically tells you where to start looking for the root cause. When something goes wrong, you need to look through your log messages and figure out important things like which device saw the problem first. ![]() One of the keys to effective network management is network clock synchronization on all network devices.
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