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PTP (Precision Time Protocol) is a protocol that enables clocks to be synchronised with a theoretical accuracy of the order of a nanosecond. PTP is the protocol to be used for all sensitive applications (energy, industry, audiovisual, finance, transport, and so on). This protocol works on local networks, but it is also able to operate over very long distances. This makes it particularly useful for extensive networks with several remote sites.

When a network becomes very extensive, it is possible that not all clocks are used for the same purposes and that they do not require the same quality of synchronisation. With no way of dividing a network, it is mandatory to maintain the highest accuracy for all clocks, which involves unnecessary costs. Indeed, the PTP protocol only provides one master clock (GMC, for Grandmaster Clock) by network.

The Global Navigation Satellite System (GNSS) consists of a constellation of satellites placed in space. They aim at providing accurate information on position and time to receivers located on Earth. This allows providing positioning, navigation and time synchronisation data (PNT for Positioning, Navigation, Timing).

According to Gartner, 45% of companies worldwide will have suffered a cyberattack by 2025. Nowadays, a cyberattack occurs every 39 seconds. In this context where cyberattacks are on the rise and even more complex, logging of information systems turns out to be a central solution for cybersecurity. Logging enables to be responsive to security incidents but also to be prepared and prevent them from happening.

Time synchronisation is paramount in the Internet of Things (IoT). In industrial IoT for example, accurate synchronisation can prevent production errors by ensuring that sensors and machines work together.

In security applications such as the supervision of critical infrastructures, time synchronisation allows for precise correlation of events recorded by different devices (time clocking terminals, security cameras), centralised in a master server.

To synchronise clocks across a local area network (LAN), it is necessary to measure the transmission delay caused by network’s technical and usage factors.

When a machine receives a message with a timestamp from a master clock, a delay is introduced due to the distance to this clock. Indeed, if a message travels along one metre of optical fibre, or crosses several different data centres, the transmission time may vary and introduce a variable delay. As a result, it is better to know this latency to synchronise a clock correctly.

Network Time Security (NTS) is a protocol which has been developed for securing communications between clients and time servers of the NTP protocol (Network Time Protocol).

NTP is an old protocol which has been developed at a time where security was less of a concern as today. As it was much criticized these last few years for its lack of security which made it vulnerable to several types of attacks (man-in-the-middle, spoofing, replay), NTS decided to add authentication and encryption layers to NTP exchanges, thus protecting them from these attacks.

There are many protocols available to synchronise clocks within a network infrastructure. The most widely used are NTP and SNTP, but when the highest possible level of accuracy is required, the PTP protocol (Precision Time Protocol) is chosen.

PTP has been introduced in 2002 via the IEEE 1588 standard which has known many evolutions since (the last version of the standard dates back to 2019).

One of PTP’s most important algorithmic building blocks is the BMCA (Best Master Clock Algorithm). BMCA enables to determine which clock, among those available on the network, will provide the time reference for the entire infrastructure.

The economic figures for the transport sector following the covid crisis have been available for a few months now, and what we can say is that the transport sector has bounced back well, both in France and internationally.

In order to establish synchronisation mechanisms within a local network, the first thing to do is choosing the right protocol. Indeed, many protocols are available for synchronising equipment within a network (PTP, NTP, SNTP, and so on). The first answer would be using the NTP protocol.