• Title/Summary/Keyword: NTP(Network Time Protocol)

Search Result 8, Processing Time 0.335 seconds

An Imbedded System for Time Synchronization in Distributed Environment based on the Internet (인터넷 기반 분산 환경에서 시각 동기를 위한 임베디드 시스템)

  • Hwang So-Young;Yu Dong-Hui;Li Ki-Joune
    • Journal of KIISE:Computing Practices and Letters
    • /
    • v.11 no.3
    • /
    • pp.216-223
    • /
    • 2005
  • A computer clock has limits in accuracy and precision affected by its inherent instability, the environment elements, the modification of users, and errors of the system. So the computer clock needs to be synchronized with a standard clock if the computer system requires the precise time processing. The purpose of synchronizing clocks is to provide a global time base throughout a distributed system. Once this time base exists, transactions among members of distributed system can be controlled based on time. This paper discusses the integrated approach to clock synchronization. An embedded system is considered for time synchronization based on the GPS(Global Positioning System) referenced time distribution model. The system uses GPS as standard reference time source and offers UTC(Universal Time Coordinated) through NTP(Network Time Protocol). A clock model is designed and adapted to keep stable time and to provide accurate standard time with precise resolution. Private MIB(Management Information Base) is defined for network management. Implementation results and performance analysis are also presented.

A Network Time Server using CPS (GPS를 이용한 네트워크 시각 서버)

  • 황소영;유동희
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.8 no.5
    • /
    • pp.1004-1009
    • /
    • 2004
  • Precise time synchronization is a main technology in high-speed communications, parallel and distributed processing systems, Internet information industry and electronic commerce. Synchronized clocks are useful for many leasers. Often a distributed system is designed to realize some synchronized behavior, especially in real-time processing in factories, aircraft, space vehicles, and military applications. Nowadays, time synchronization has been compulsory thing as distributed processing and network operations are generalized. A network time server obtains, keeps accurate and precise time by synchronizing its local clock to standard reference time source and distributes time information through standard time synchronization protocol. This paper describes design issues and implementation of a network time server for time synchronization especially based on a clock model. The system uses GPS (Global Positioning System) as a standard reference time source and offers UTC (universal Time coordinated) through NTP (Network Time protocol). Implementation result and performance analysis are also presented.

A Study on Time Synchronization Method for IED Using IEC 61850 (IEC 61850용 IED의 시각 동기 방안 연구)

  • An, Yong-Ho;Kim, Byeong-Heon;Jang, Byung-Tae;Song, In-Jun;Kim, Young-Don;Jang, Su-Hyeong;Kim, Kyung-Ho
    • Proceedings of the KIEE Conference
    • /
    • 2008.07a
    • /
    • pp.277-279
    • /
    • 2008
  • 현재 많은 전력계통용 보호제어 벤더들은 변전소 자동화 국제표준 프로토콜인 IEC 61850을 적용한 전력 장비들을 개발하여 변전소에 적용하고 있다. 이러한 많은 장비들은 표준화된 IEC 61850 프로토콜을 적용하여 상호 호환성을 유지하였으며, 기존에 적용되고 있는 표준화된 기술들을 채택하고 있다. 변전소 장비들은 정밀한 시간 동기를 위해서 표준화된 시각 동기 프로토콜인 SNTP(Simple Network Time Protocol)나 NTP(Network Time Protocol)를 사용하고 있다. 본 연구에서는 IEC 61850 프로토콜을 적용한 IED가 시각 동기 장치로부터 시간 동기화되는 방안에 대해 연구하였다.

  • PDF

Time Synchronization of the Monitoring Data for the VoIP User Assessment of Voice Quality Measurement (인터넷전화 이용자 체감품질 측정을 위한 측정데이터 간의 시간동기화)

  • Kweon Tae-Hoon;Hwang Hyae-Jeong;Lee Seog-Ki;Song Han-Chun;Won Seung-Young
    • The Journal of the Korea Contents Association
    • /
    • v.5 no.4
    • /
    • pp.227-236
    • /
    • 2005
  • We study, in terms of VoIP user assessment of voice quality, the synchronization of measurement system is important. Commonly the synchronization system uses NTP(Network Time Protocol) or GPS(Global Positioning System), these synchronization method has time error of distance, system overhead of data processing, and system specialized clock error. we propose and implement the synchronization method to correct time error between two measurement system in the internet. So the time synchronization of systems can get time error, then user assessment of voice quality become reliable.

  • PDF

Technical Trend of Time Synchronization Equipment in Naro Space Center (나로우주센터 표준시각 동기화장비 기술동향)

  • Han, Yoo-Soo;Choi, Yong-Tae
    • Current Industrial and Technological Trends in Aerospace
    • /
    • v.6 no.1
    • /
    • pp.116-123
    • /
    • 2008
  • In the launch mission, mission control systems and tracking systems need time synchronization for data monitoring and data analysis. There are several standards for time synchronization and an adequate standard is selected according to the requirement of time accuracy and cost among time synchronization standards. Oscillators are used to maintain time accuracy. There are some kinds of oscillators with diverse characteristics and an adequate oscillator can be adopted according to time accuracy. In this paper, we will specify characteristics of several oscillators and standards generally used for time synchronization. And we will also introduce TSDN(time synchronization and display network) for time synchronization in Naro Space Center.

  • PDF

A study on the Set-top Box System Recovery using Network Time Synchronization (네트워크 시간 동기화를 활용한 효과적 셋톱박스 시스템 복구 방안에 관한 연구)

  • Han, Kyung-Sik;Kim, In-Ki;Min, Tae-Hoon;Sonh, Seung-Il
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2013.05a
    • /
    • pp.647-649
    • /
    • 2013
  • This paper is the study of effective recovery system in the android set-top box, using NTP (Network Time Protocol). Because of Response to the user react quickly in case of a set-top box, needs compared to other electronic products, set-top box is one of always powered features to work at home. But general-purpose OS such as Android-based set-top box have to reset for cache & main memory initialization. In this paper, we introduce system reset & recovery by NTP client utilizing.

  • PDF

A standardization of AGNSS-Packet Timing Hybrid for a Synchronization of Femtocell (펨토셀 기지국 동기 획득을 위한 AGNSS-Packet Timing 하이브리드 표준화)

  • Kim, Jung-Hoon;Lee, Ji-Hun;Shin, Jun-Hyo;Jeong, Seok-Jong
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.36 no.12B
    • /
    • pp.1611-1622
    • /
    • 2011
  • The synchronization is one of the important issues for successful operation of femtocell. The synchronization of femtocell is distinctly different from that of larger wireless base stations in a number of important respects such as 1) The femtocell is located in indoor environment which may make it difficult to receive the adequate GNSS signals. 2) The backhaul of femtocell is connected to the public network which may have more PDV than private network. 3) The entire cost of femtocell needs to be very low. In our thesis, we investigate the candidate solutions including AGNSS (Assisted GNSS), NTP (Network Time Protocol), PTP (Precision Timing Protocol) and Cellular Network Listen for indoor timing solution. We propose the AGNSS-PTP Hybrid scheme which can improve time and frequency quality by selecting the better reference between AGNSS and PTP, and cover the standard status which are under discussion from IEEE, ITU-T, and IETF.

CoAP-based Time Synchronization Algorithm in Sensor Network (센서 네트워크에서의 CoAP 기반 시각 동기화 기법)

  • Kim, Nac-Woo;Son, Seung-Chul;Park, Il-Kyun;Yu, Hong-Yeon;Lee, Byung-Tak
    • Journal of the Institute of Electronics and Information Engineers
    • /
    • v.52 no.3
    • /
    • pp.39-47
    • /
    • 2015
  • In this paper, we propose a new time synchronization algorithm using CoAP(constrained-application protocol) in sensor network environment, which handles a technique that synchronizes an explicit timestamp between sensor nodes not including an additional module for time-setting and sensor node gateway linked to internet time server. CoAP is a standard protocol for sensor data communication among sensor nodes and sensor node gateway to be built much less memory and power supply in constrained network surroundings including serious network jitter, packet losses, etc. We have supplied an exact time synchronization implementation among small and cheap IP-based sensor nodes or non-IP based sensor nodes and sensor node gateway in sensor network using CoAP message header's option extension. On behalf of conventional network time synchronization method, as our approach uses an exclusive protocol 'CoAP' in sensor network, it is not to become an additional burden for synchronization service to sensor nodes or sensor node gateway. This method has an average error about 2ms comparing to NTP service and offers a low-cost and robust network time synchronization algorithm.