Using 1 clock you have no choice. You have to trust its time

Using 2 clocks you will not know which provides the right time

Using 3 or more opens possibility to consider what time might be

Above philosophical principle evokes very serius implications and should be taken into account when designing synchronization. Furthermore, understanding that NTP/PTP timeservers know nothing about client side time makes synchronization really a challenge for technology and science. So, how to design robust synchronization ? Below there are some most important considerations and tips for building:

  1. Synchronization - use known and trusted sources of UTC ref. time
  2. Monitoring          - involve continuous validation of UTC traceability
  3. Robustness         - lunch backups and redundacy - keep integrity !

  #1 Are you sure of using true UTC ? We mostly beleive the UTC, GMT, GPS, TAI/POSIX - are all the same. This is not true. The offset of UTC to GPS is 17 seconds. Offset of atomic time TAI to UTC is 36 leap seconds. Beside GMT bases on astronomic observations at the time UTC, TAI (POSIX) all bases on atomic time scale.

 #2 Does your solution support LEAP SECOND ? This might cause ERROR  of 1-2 seconds (read report )

 26th of Jan 2016 GPS 13us error .

#3 Can we really trust GPS ?  On the 26th of Jan 2016 during decommissioning of the satellite SVN-23 the GPS controsegment has obviously uploaded corrupted data which caused the UTC correction parameter to be wrong. This set of parameter consisting of a static offset, a linear term, a reference time and leap second information is used to relate GPS system time to UTC. Normally the A0 parameter which represents the static offset of GPS time to UTC (excluding the number of leap seconds) at time of upload is about a few nanoseconds. After upload, this parameter jumped to about -13.7us, but what if error could be second, two or all 36 seconds ?


#4 GPS jamming/spoofing. Every day for up to ten minutes near the London Stock Exchange, someone blocks signals from the global positioning system (GPS) network of satellites. Navigation timestamps on trades made in financial institutions can be affected. The incidents are not a cyber-attack by a foreign power, though. The most likely culprit covertly monitors such events but problem is not well known public.

The GPS signal is very weak, 20-watt light bulb viewed on Earth from 20,000 km (12,000 miles). The jammers are cheap about $80 (£50) and public available. The bubbles of electromagnetic noise they create interfere with legitimate GPS users. They can disrupt civil aviation and kill mobile-phone signals, too.

Experts worries that criminals or terrorists could knock out GPS for an entire city or shipping lane anywhere in a flash. Even without North Korean-sized contraptions, the jamming can be substantial. Suitcase-sized devices on sale on the internet claim a range of 100-1,000 meters.

 On the 13th of May 2016 FSMLabs has detected GPS jamming cyber-attack to London Equinix LD4 data center. Jamming and spoofing devices are radio frequency transmitters that intentionally block (jam) interfere or symulate wrong satellite data with lawful communications, such as GPS driven time systems. Both: jammers and dignal spoofers are illegal to market, sell, or use for cyber-attacks. Missing leap second support for UTC can cost much more.


GPS jammer 


(read more abot jamming)

#5 Misuse of Timing (news from BBC). There are already many good known examples of misuse of timing. In November 2015 Barclays fined $150M over misconduct in foreign exchange trading. A microsecond hold period was introduced between a customer order being received and its execution. If markets moved in favour of the bank, the trade went through. If the client would have benefited, the trade was turned down. Also Thomson Reuters released data 15 ms early and Deutsche Borse shut down.  

#6 UTC Falsetickers are any product (can be any NTP/PTP server) that claim to provide UTC but they provide falsification time. There are 2 kinds of falsetickers: natural and forced artificial. Natural falseticker provides wrong time due to network traffic or asymmetry impact. Forced falsetickers provides wrong time due to planned or random human operations, including manipulations on timestamps. In such case The Marzullo's Algorithm can be taken into account. Algorythm invented by Keith Marzullo for his Ph.D. dissertation in 1984 is an agreement algorithm used to select sources for estimating accurate time from a number of noisy sources. A refined version of it, renamed the intersection algorithm, forms part of the modern Network Time Protocol. 


Robustness Synchronization. Considering multiple ref. source of time The Marzullo's algorithm can be taken into account. In any case it is always good to monitor local time by tracing its UTC source and compare it to NTA (National Time Authority) primary reference UTC(k) /if available/. Also redundancy can help improve robustness of synchronization by using a larger than one number of independent UTC ref. sources (or several servers). Continous UTC Time Monitoring and Time Auditing Facility is becoming to be more and more important tool to build real robustness synnchronization.


Finally the Cryptographic Timestamping (TSA rfc3161) is the only tool that provides non-repudiation, validity, authentication, and integrity of IT network synchronization.

Time is the critical factor in separating cause from effect and the global market is continuously decreasing time intervals for single technical or business action to be taken. Synchronization reminds strategic for:

Finance (level of single microseconds)  NTS-5000HFT
Telecom (level of microseconds)
Power Distribution (level of microseconds)
Smart City / M2M (level of miliseconds)
Security & Monitoring (level of seconds)
Encrypiotion (level of seconds)
Medicine & Science (level of nano-pico seconds)
Public Administration (level of minutes and hours)
IoT/Cloud (level of miliseconds)

Daily business requires time dematerialization. Cryptographic RFC3161 Timestamping is an important mechanism for the long-term preservation of digital signatures, time "sealing" of data objects - to prove when they were created, received etc. - all with properties such as:




  • non-repudiation,
  • authentication,
  • validity
  • integrity,

Electronic clocks in most computers keep inaccurate time.  Some clock variations are random, caused by env. or electronic variations, others are systematic, caused by a miscalibrated clock. Clearly, having any sort of meaningful time synchronization is almost impossible if clocks are allowed to run on their own (free run). In some env., this lack of synchronization isn’t a big issue. However, in most modern networked computing environments, time synchronization is important.

To reduce confusion in shared filesystems (IoT/Cloud). Billing services must know the time accurately. Some financial services even require highly accurate timekeeping regulated by the law (ESMA FiFID II). Sorting emails can also be difficult if time & date are incorrect. Tracking security breaches, network usage, or problems affecting a large number of components can be nearly impossible if time stamps inide LOG files are inaccurate. Applications such as cyptographic key management and secured document transmission (B2B( may require using accurate stamps which match unencoded time stamps to help assure document authenticity.

@TELECOM - Synchronization is still needed today and in future for mobile applications networks to:

  • Stabilize the radio frequencies used by the mobile base station (BTS)
  • Allow efficient spectrum usage
  • Avoid radio interference between neighboring cells
  • Allow seamless hand over between cells

Poor synchronization within a telecommunications network may have important impacts on the end user:

  • The communication can degrade (voice communication can become inaudible).
  • The throughput of data connections in the networks can reduce.
  • The network’s connections (in the case of the internet) might even be totally lost.
  • In the case of mobile communications, hand over between cells could fail and quality of experience degrade

Click here to enlarge Telecom Infrastructure picture in PDF 


  • Precise timing is not essential for electronic trading since matching engines are based on sequence, but cryptography secured LOG files must be provided for future audits and monitoring
  • Algorithmic trading & High Frequency Trading (HFT) need highly precise & accurate timestamping to understand order of execution
  • Low latency and co-location Facilitates HFT (~1M trades per second) between co-located traders 
  • Arbitrage Profiting from price differences between markets