NTPNetwork Time Protocol NTPNetwork Time Protocol NTPNetwork Time

NTP（Network Time Protocol） • 体系结构（网络）

NTP（Network Time Protocol） • 体系结构（单机）

典型时间同步协议 • NTP（Network Time Protocol） • DMTS （Delay Measurement Time Synchronization） • RBS （Reference Broadcast Synchronization） • TPSN （Timing-sync Protocol for Sensor Networks） • HRTS （Hierarchy Referencing Time Synchronization Protocol） • FTSP （Flooding Time Synchronization Protocol） • GCS （Global Clock Synchronization）

RBS （Reference Broadcast Synchronization） • 接收者同步的基本依据：接收者时 间相移均值为 0

TPSN（Timing-sync Protocol for Sensor Networks） • 否定：DMTS RBS • 否定之否定：RBS TPSN • TPSN：双报文交换的发送者 接收者同 步

TPSN（Timing-sync Protocol for Sensor Networks） T 2 节点A Request T 3 Reply 同步点 节点B T 1 T 4

HRTS（Hierarchy Referencing Time Synchronization Protocol） n 2 BS BS n 1 n 3 (b) (a) n 2 BS BS n 1 n 3 n 4 n 1 (c) n 3 n 4 (d)

FTSP（Flooding Time Synchronization Protocol） • 同步精度高 • 程实用性强 • 强调实现细节

主要参考文献（详见原著） • • • [1] Elson J. , Römer K. . Wireless sensor networks: a new regime for time synchronization. ACM SIGCOMM Computer Communication Review, 2003, 33(1): 149 -154. [3] Elson J. , Girod L. , Estrin D. . Fine-grained time synchronization using reference broadcasts. In: Proc. 5 th Symposium on Operation System Design and Implementation, Boston, 2002, 147 -163. [4] Ganeriwal S. , Kumar R. , Srivastava M. . Timing-sync protocol for sensor networks. In: Proc. 1 st ACM Conference on Embedded Networked Sensor Systems, Los Angeles, 2003, 138 -149. [7] Mills D. L. . Network time protocol (Version 3) specification, implementation and analysis. University of Delaware, DARPA Network Working Group Report: RFC-1305, 1992. [13] Miklos M. , Branislav K. , Gyula S. , Akos L. . The flooding time synchronization protocol. In: Proc. 2 th ACM Conference on Embedded Networked Sensor Systems, Baltimore, 2004, 39 -49. [14] Su Ping, Delay measurement time synchronization for wireless sensor networks, Intel Research. Berkeley Lab, 2003. [19] Dai H. , Han R. . TSync: a lightweight bidirectional time synchronization service for wireless sensor networks. ACM Mobile Computing and Communications Review, 2004, 8(1): 125 -139. [26] Li Q. , Rus D. . Global clock synchronization in sensor networks. IEEE Transactions on Computers, 2006, 55(2): 214 -226. [34] Ernst U. , Pawelzik K. , Geisel T. . Delay-induced multistable synchronization of biological oscillators. Phys Review E, 1998, 57: 2150 -2162. [36] Hong Y. , Scaglione A. . A scalable synchronization protocol for large scale sensor networks and its applications. IEEE Journal of Selected Areas in Communications, 2005, 23(5): 1085 -1099.