Five Minute Facts on Packet Timing NTP deployments of larger networks usually have NTP servers connected in a tree structure, such as the one in Figure 1. Note that the Stratum 1 servers typically have a GNSS time source, but the higher Stratum servers do not. Instead, they act as both a server and a […]
DIY NTP message extensions
Five-minute facts about packet timing So, you ‘ve been thinking that NTP messages should have some additional fields, but they’re not in standard. What can you do? You can define your own message extension; that’s what you can do! NTPv4, defined by RFC 5905, defines extensions to NTP messages called Extension Fields (EFs). That is […]
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 […]
Genlock in a networked world
Five-minute facts about packet timing Once upon a time there was an industry that needed data sharing and time synchronization among devices that were spatially disbursed. So, the industry developed standards for data transfer and timing signals that each device could interface to, and everything worked. But the technical professionals in the industry did not […]
Network Time Security (NTS): Updated security for NTP
Five-minute facts about packet timingNetwork Time Protocol version 4 (RFC 5905) is a spectacularly successful network time transfer protocol. It can be found in almost every IP network. Often NTP messages will traverse leased lines or the “public internet”. Therefore, it is especially important that an NTP client can determine that the NTP server is […]
The Root of All Timing: Understanding root delay and root dispersion in NTP
Five Minute Facts About Packet Timing If you examine an NTP packet you will see the fields root delay and root dispersion. See the diagram from RFC 5905 in Figure 1 bellow, which defines NTP version 4, the current version. You might ask what is with all this “root” stuff? Root in this case refers […]
GNSS Spoofing and how to mitigate it
Five Minute Facts About Packet Timing In a previous post I talked about GNSS jamming and how to mitigate it. Today I will discuss GNSS spoofing. Once again GNSS means Global Navisgation Satellite System, which includes not only GPS, but similar systems like the European Galileo. GNSS jamming is bad, but at least you always […]
GNSS jamming and how to mitigate it
Five Minute Facts About Packet Timing This post discusses GNSS jamming, for a discusstion of GNSS Spoofing see the follow up post. Before a timeserver transmits messages with timing information it usually gets that information from a GNSS receiver. That is a Global Navigation Satellite System. Such systems include the Global Positioning System (GPS), Galileo, […]
Performance Level Options for the Meinberg HPS100 card
Five Minute Facts About Packet Timing By Andreja Jarc. I promised you in my earlier post, that I will update you on how to pick the right license model and performance level of your High-Performance Synchronization (HPS100) card. Each performance level defines a number of packets / second or number of unicast slaves that can […]
Meinberg High-Performance Sync card (HPS100)
Five Minute Facts About Packet Timing By Andreja Jarc. Those of you who know Meinberg may have noticed that Meinberg typically does not talk about licenses. The reason for this is, that Meinberg, in most cases, does not charge you extra for enabling specific features or functions. With our free lifetime support and firmware update […]