Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/19643
標題: 以同步時鐘做分時多工跨越乙太網路異常分析
Anomaly Analysis of TDM over Ethernet via A Synchronization Clock
作者: 施冠州
Shih, Kuan-Chou
關鍵字: Synchronization Clock
同步時鐘
Synchronous Ethernet
TDM over Ethernet
同步乙太網路
分時多工跨越乙太網路
出版社: 資訊科學與工程學系所
引用: [1] 黃景廉,”ISUP信號系統的實現,” Journal of Northwest University for Nationalities(Natural Science), vol 25,pp.14-18,Mar. 2004. [2] 范亞希,王一超,” TDM over Ethernet 技術及應用,”通訊世界, pp.40-41, Mar. 2003. [3] 田輝,石友康,” 乙太網技術及標準化新進展,” 通信世界週刊, pp.B1-B2, Oct. 2006. [4] 周昭榮,”EPON系統中的TDMoEth 技術,” 電信科學 , Vol. 10, PP. 103-105, Oct. 2007. [5] ITU-T RECOMMENDATION G.703 (2001), Physical/electrical characteristics of hierarchical digital interfaces [6] ITU-T RECOMMENDATION G.811 (1997),Timing Characteristics of Primary Reference Clocks. [7] ITU-T Recommendation G.812 (2005) Timing requirements of slave clocks suitable for useas node clocks in synchronization networks [8] ITU-T Recommendation G.813 (2003), Timing requirements of SDH equipment slave clocks (SEC). [9] ITU-T Recommendation G.8261 (2006), Timing and Synchronization aspects in Packet Networks. [10] ITU-T Recommendation G.8262 (2007), Timing characteristics of synchronous Ethernet equipment slave clock (EEC) [11] ITU-T Recommendation I.363.1 (1996), B-ISDN ATM Adaptation Layer specification:Type 1 AAL. [12] IEEE-1588 - Standard for a Precision Clock Synchronization Protocol for Networked Measurementand Control Systems. [13] Thomas D. Nadeau ,Vishal Sharma ,Ashwin Gumaste” NEXT-GENERATION CARRIER ETHERNET TRANSPORT TECHNOLOGIES,” IEEE Communications Magazine ,PP67-68,March 2008. [14] Zier, L. Fischer, W. Brockners, F. “Ethernet-based public communication services: challenge and opportunity,” IEEE Communications Magazine, Vol: 42, Issue: 3, pp. 88- 95, Mar. 2004 [15] Sungwon Lee,” An Enhanced IEEE 1588 Time Synchronization Algorithm for Asymmetric Communication Link using Block Burst Transmission,” IEEE COMMUNICATIONS LETTERS, VOL. 12, NO. 9, PP.687-689, Sep. 2008 [16] T. Cooklev, J. C. Eidson, and A. Pakdaman, “An implementation of IEEE 1588 over IEEE 802.11b for synchronization of wireless LAN area network nodes,” IEEE Trans. Instrumentation and Measurement, vol. 56, no. 5, pp. 1632–1639, Oct. 2007. [17] P. Ferrari, A. Flammini, D. Marioli, and A. Taroni, “IEEE 1588 based synchronization system for a displacement sensor network,” IEEE Trans. Instrumentation and Measurement, vol. 57, no. 2, Feb. 2008. [18] A. Vallat and D. Scheuwly, “Clock synchronization in telecommuni- cations via PTP (IEEE 1588),” in Proc. IEEE International Frequency Control Symposium Joint with the 21st European Frequency and Time Forum, pp. 334–341, May 2007. [19] Silvana Rodrigues,” IEEE-1588 and Synchronous Ethernet in Telecom,” 2007 International IEEE Symposium on Precision Clock Synchronization (ISPCS)for Measurement, Control and Communication, PP.138-142, Oct. 2007. [20] SHI Yu-juan; ZHAO Jian; FANG Hai-yan; LI Bo,” Analysis and Implementation of the Time Synchronization Protocol IEEE1588,” Instrumentation Technology, Vol. 9, PP.12-14, Sep. 2007. [21] Xiantao Wu, chengzhi Wu,” Synchronous Ethernet Networks,” Modern Transmission, Vol. 6, PP.70-74, Jun. 2007. [22] Pinchas, M., “PTP slave clock accuracy on circuit emulation system performance,” Precision Clock Synchronization for Measurement, Control and Communication, IEEE, PP. 44-48, Sep. 2008. [23] Sung-Hwan Kang , Jong-Hoon Eom , Yong-Sik Kwon, Sung-Ho Kim ,” Propagation Delay Measurement Using A Single-TimeSync Frame in Bridged Local Area Networks,” Advanced Language Processing and Web Information Technology, IEEE, PP.460-465, Jul. 2008. [24] Silvana Rodrigues,” Combining Synchronous Ethernet and IEEE-1588™ for use in Telecom,” 2006 Conference on IEEE-1588. [25] Jean-Loup Ferrant,” SDH synchronization,” ITSF, London Oct. 2005. [26] IETF RFC-4553, Structure-Agnostic Time Division Multiplexing (TDM) over Packet (SAToP), A. Vainshtein and Y. J. Stein, June 2006. [27] http://www.edntaiwan.com/article-1986-實淞DH時鐘的注意事項-Asia. html,實現SDH 時鐘的注意事項, Ullas Kumar, Aug. 2005. [28] http://www.telecom-sync.com/index.php [29] http://www.pcs.csie.ntu.edu.tw/course/pcs/2004/19_3G_Overview .pdf, Introduction to 3G
摘要: 對於下一代網路(NGN)有個共識,就是它將是一個以高速封包交換技術為基礎的網路,而且這個網路能夠同時間承載如語音、影像、資料等多種服務。此外,由於封包支配網路訊務大多以乙太網路或網路協定格式封裝。企業及住宅用戶已熟悉乙太網路技術,而且要求簡單、價格低廉及高速的通用乙太網路服務,所以乙太網路是一種被廣泛應用在網路上的技術,而IP網路協定在更多環境中以乙太網路來承載,乙太網路將成為在下一代網路技術中其中一個主流。 然而現在語音服務在大多數的情況下,是以分時多工網路(TDM)來承載,而TDM已被廣泛地利用在如同步數位階層(SDH)技術上。因此,在現階段網路要發展到下一代網路這段期間內,以同步數位階層為基礎的分時多工網路,及以網際網路協定(IP)或乙太網路為基礎的封包交換網路,將長期共存下去。封包交換網路沒有中心時鐘或同步的觀念,資料從本地端被傳送到達另一端在某個未知的時間;既然如此,設備就必須有穩定、準確的時鐘源來校正它所傳送及接收的資料。封包交換網路得提供必需的時間復原,以確保分時多工跨越乙太網路服務。 本論文將利用下一代網路中,與分時多工網路連接的中繼閘道器為主的完整鏈路進行異常障礙分析,它是典型的分時多工跨越乙太網路結構。在封包交換網路的工作與保護路由切換,引起話務不連續的異常現象;為了解決這樣的異常障礙,分別以即時傳輸協定(RTP)封包分析、交換機信令分析、傳輸路由量測後,歸納得到同步不良是造成訊務無法銜接的主要原因。本論文提出將同步數位階層輸出E1信號做時序重整(retiming),做為中繼閘道器的做參考同步信號;這樣可使輸入中繼閘道器的E1信號在最大相對時間間隔誤差(MRTIE)達到主參考時鐘產生的52.5奈秒標準;更能讓中繼閘道器輸出的E1信號,由超出同步數位階層自由振盪4.6微秒,改善到低於主參考時鐘輸出的300奈秒標準。而且在相對時間間隔誤(RTIE)也同樣有出色的表現,以線性表示相對時間間隔誤與時間的關係圖中,亦能看出變化趨於平穩。這也使得90%的異常路由障礙得以排除。
There is a consensus that the next generation network (NGN) is a network based on high-speed packet technology, and the network can carry multi-service such as voice, video and data simultaneously. Furthermore, a majority of packet-dominated network traffic is either encapsulated using Ethernet or the Internet Protocol (IP). Enterprises and residential customers familiar with Ethernet technology are demanding a simple, inexpensive and high-speed universal Ethernet service. Therefore, Ethernet is a kind of widely applied network technology, and IP protocol is carried over Ethernet under most circumstances. Ethernet will be one of the mainstream technologies of NGNs. However, the present voice service is carried on TDM network under most circumstances, and TDM based technologies such as Synchronous Digital Hierarchy (SDH) have been widely deployed. Thus, during the transition period for current networks to evolve to NGNs, TDM-based networks and packet-based networks, such as SDH and IP as well as Ethernet will coexist for a long time. Packet-based networks are implemented without the concept of central clocks or synchronization. Data is transmitted at one location and arrives at the other at some uncertain time. In this case, the equipment must have a steady, accurate clock source with which to align its transmitted and received data. Packet-based networks provide the necessary clock recovery to enable TDM over Ethernet services. This thesis focuses on the anomaly barrier analysis of a complete link that connects a TDM network to a Trunking Gateway (TG) in the NGN. This is a typical network architecture of TDM over Ethernet. In the PSN, however, switching the working path to the protection path could lead to an abnormal problem - network traffic is disrupted and services are discontinued as a consequence. This is a technical problem of great research interest. After analyzing real-time protocol (RTP) packets and switching signals via transmission measurement, we find that lack of precise synchronization is the main cause of the abnormal traffic problem. This thesis proposes a novel method of retiming E1 signal of the SDH output and using it as a reference synchronization signal for Trunking Gateway. The proposed retiming method can generate the E1 signal of TG input in comply with the maximum relative time interval error (MRTIE) requirement of 52.5ns specified in the PRC-Generation standard. The method successfully reduces the E1 signal error level to a smaller margin of 300ns than that of the PRC-output standard. This is a significant improvement as compared to the previous free-running 4.6μs of SDH. The proposed method demonstrates an outstanding capability not only in reducing relative time interval error (RTIE) but also in stabilizing RTIE. As a result of this, 90% abnormal path barriers are eliminated effectively.
URI: http://hdl.handle.net/11455/19643
其他識別: U0005-2306200915181400
文章連結: http://www.airitilibrary.com/Publication/alDetailedMesh1?DocID=U0005-2306200915181400
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