Five Minute Facts about Packet TimingWelcome to the next installment on my series of posts about timing equipment resilience in the language of the IEEE P1952 project. It’s time to talk about recovery … for clocks that is. The first question about timing equipment recovering from an adversity is: Should it? Wait, what? I mean […]
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IEEE 1952 PNT Resilience Levels: Detecting Adversities
Five Ten Minute Facts about Packet Timing (sorry this one needs to be a little longer)In my last post I talked about the behaviors that timing equipment should exhibit to achieve resilience in the face of adverse conditions, according to the draft standard IEEE P1952. One of these is the ability to detect an adversity […]
IEEE 1952 PNT Resilience Levels
Five-minute facts about packet timing A while back I posted on the start of an standards development project: IEEE 1952, or P1952 as they call it in the IEEE standards world. The P stands for project, and that means that it has not yet grown up to become a published standard yet. That is likely […]
How to pick an oscillator for holdover
5 Minute Facts About Packet Timing You have a holdover requirement, and you need to select an oscillator from the choices presented to you by your timing equipment vendor. More stable oscillators are better, but they also cost more. You want to know which is the least expensive option that meets your requirement. However, the […]
What is gPTP?
Five-minute facts about packet timing gPTP is the name given to the IEEE 802.1AS profile of PTP. gPTP is only sort of a PTP profile. That is because gPTP is independently specified. In other words, rather than stating that it requires, forbids, and allows certain options defined in IEEE 1588, it specifies all these features […]
What happened at the last ISPCS PTP Plugfest
Five Minute Facts about Packet Timing After three years off for the pandemic, which felt like thirty, the ISPCS has been meeting in person again. In Vienna in 2022, London in 2023, and this year it will be in Tokyo in October. The ISPCS is the International Symposium on Precision Clock Synchronization. It’s a workshop […]
Problems with Unicast PTP
Five Minute Facts about Packet Timing When PTPv2 was defined the IEEE 1588 working group recognized that some networks, which could benefit from precise network timing, would not support multicast protocols. So, a unicast version of PTP was defined in IEEE 1588-2008. The ITU-T defined two PTP Profiles using unicast PTP, which have been used […]
What is a Synchrophasor?
By Allan Armstrong and Doug Arnold The power grid is experiencing rapid change. Population growth and highly-consumptive industries – datacenters, IC fabs, mining & metal smelting – are driving capacity expansion. Green energy is rushing in to help, but solar and wind are distributed through the network and less predictable. Unlike thermal power plants, the […]
When a Boundary Clock is the Grandmaster in a PTP network
5 Minute Facts About Packet Timing I recently received some questions about Boundary Clocks (BCs) becoming Grandmasters (GMs) from a blog reader sent to my email. Yes, I really answer them. It was especially interesting because we spent a lot of time discussing stepsRemoved and BC/GMs at a recent meeting of the Network Synchronization and […]
A Step Toward a More Inclusive Terminology for PTP
Five Minute Facts about Packet Timing The IEEE Standards Association will soon published IEEE 1588g-2022, an amendment to IEEE 1588-2019. The amendment recommends optional alternative terms for master and slave. The terms selected are: The obvious concern is the one about the insensitivity of using the institution of slavery as a technical analogy. Another concern […]