r5 - 2011-07-27 - 07:34:14 - BorisSieklikYou are here: NTP >  Dev Web > GoogleSummerOfCode > GSoC2011ClockModelsBoris
NTP users are strongly urged to take immediate action to ensure that their NTP daemons are not susceptible to being used in distributed denial-of-service (DDoS) attacks. Please also take this opportunity to defeat denial-of-service attacks by implementing Ingress and Egress filtering through BCP38.

ntp-4.2.8p15 was released on 23 June 2020. It addresses 1 medium-severity security issue in ntpd, and provides 13 non-security bugfixes over 4.2.8p13.

Please see the NTP Security Notice for vulnerability and mitigation details.

Are you using Autokey in production? If so, please contact Harlan - he's got some questions for you.

Clock Models (Boris) (GSoC 2011)


The goal of this project is to study the different clock models used in NTP, understand the basicas and operation of the NTP itself and propose and improved NTP clock algorithm.

In my project, I will make a research to understand what already exists in the NTP clock algorithms. I will then test this algorithms using the NTP build-in simulator and evaluate their performance. I will also try to propose the new improved algorithm using both mathematical/statistical models and NTP - build-in simulator. Furthermore, I will study the parameter which gives us a explicit connection between polling interval and accuracy of the synchronization process. At this moment, I am writing a progress reports about the basic concepts of the NTP.

Related Items: ClockAlgorithms


First Progress report

First progress report contains the information about the Frequency-Locked Loops and describes their detailed operation. It also decribes the mechanism how the FLL locks to the reference frequency.

Second Progress report

Second progress report contains the information about the Phase-Locked Loops and describes their detailed operation. This includes the mechanism which allows the PLL to lock to the particular phase.

Third Progress report

Third progress report contains the detailed differences between the PLLs and FLLs. Moreover it describes their example of usage.


Date Task Description % Done
2011-04-25   Accepted student proposals announced on the Google Summer of Code 2011 site. DONE
2011-04-27 Community Bonding Students get to know mentors, read documentation, get up to speed to begin working on their projects. DONE
2011-05-24 Coding begins Students begin coding for their GSoC projects DONE
2011-05-24 First report First Report describes the operation of the FLLs. DONE
2011-05-28 Second Report Second Report describes the operation of the PLLs. DONE
2011-06-02 Third Report Third Report describes the differences between PLLs and FLLs. DONE
2011-06-08 Fourth Report Fourth Report describes operation of the PLLs and FLLs in NTP DONE
2011-06-08 Fifth Report Fifth Report describes the operation of the NTP in quite detail DONE
2011-06-10 Sixth Report Sixth report talks about the different clock models including the one which is used by NTP DONE
2011-07-11 Start mid-term evaluations Mentors and students can begin submitting mid-term evaluations. DONE
2011-07-15 Mid-term evaluations Mid-term evaluations deadline DONE
2011-07-29 Seventh Report I am describing the mathematical operation of the NTP, including operation of PLL types, laplace transforms and so on.  
2011-08-09 Possible week off I am planning to go on holiday, however the date has not been determined yet. I will let everybody know in advance.  
2011-08-15 Wrap-up Suggested 'pencils down' date. Take a week to scrub code, write tests, improve documentation, etc.  
2011-08-22 Firm 'pencils down' date. Mentors, students and organization administrators can begin submitting final evaluations to Google.  
2011-08-26 Final evaluation Final evaluation deadline  
2011-08-30 Code samples Students can begin submitting required code samples to Google  

Discussion and Comments

Edit | WYSIWYG | Attach | Printable | Raw View | Backlinks: Web, All Webs | History: r5 < r4 < r3 < r2 < r1 | More topic actions
SSL security by CAcert
Get the CAcert Root Certificate
This site is powered by the TWiki collaboration platform
IPv6 Ready
Copyright & 1999-2020 by the contributing authors. All material on this collaboration platform is the property of the contributing authors. Ideas, requests, problems regarding the site? Send feedback