(12) UIllt€d States Patent (10) Patent No.: US 8,068,430 B2 Geva et al. (45) Date of Patent: Nov. 29, 2011 (54) HIGH QUALITY TIMING DISTRIBUTION 2006/0227714 A1* 10/2006 Griffin et al. ............... .. 370/241 2008/0052394 A1 2/2008 Bugenhagen et al. OVER DSL WITHOUT NTR SUPPORT 2008/0075061 A1 3/2008 Hatala et al. (75) Inventors: Alon Geva, Hod Hasharon (IL); Ehud OTHER PUBLICATIONS Malik’ Shoham (IL); Yaakov stein’ ITU-T Recommendation G.991.2. This publication can be found at Jerusalem (TL) http://WWW.itu.int/ITU-T/publications/recs.htrnl. _ ITU-T Recommendation G.992.1. This publication can be found at (73) Ass1gnee: Rad Data Communications Ltd., Tel http://wvvvv.itu.int/ITU-T/publications/recs.html. A\/iv (IL) ITU-T Recommendation G.992.3. This publication can be found at http://WWW.itu.int/ITU-T/publications/recs.htrnl. - _ - - - - ITU-T Recommendation G.992.5. This publication can be found at ( * ) Not1ce. SUIJJCCL to any d1scla1mer, the term of this http:// ‘im‘inUITU_T/publications/recShtml‘ Patent 15 extended or adlusted under 35 ITU-T Recommendation G.8261. This publication can be found at U.S.C. 154(b) by 191 days. http://WWW.itu.int/ITU-T/publications/recs.htrnl. ITU-T Recommendation I.363 (ATM AAL1). This publication can (21) Appl_ No_: 12/263,893 be found at http://WWW.itu.int/ITU-T/publications/recs.htrnl. ITU-T Recommendation Y1413. This publication can be found at - _ http://WWW.itu.int/ITU-T/publications/recs.htrnl. (22) F11ed' NOV‘ 3’ 2008 International Search Report for International Application No. PCT/ IL09/01021 mailed Mar. 22, 2010. (65) Prior Publication Data * cited by examiner US 2010/0111114A1 May 6,2010 Primary Examiner * Hanh Nguyen (51) Int‘ Cl‘ 74 Attorn , A ent, or Firm * Pearl Cohen Zedek Latzer, W 8 G01 G 31/08 (2006.01) LLP H04] 3/16 (2006.01) (52) U.S. Cl. ...................................... .. 370/241; 370/350 (57) ABSTRACT (58) Field of Classification Search ................ .. 370/242, A method and System in Which a Digital Subscriber Line 370/243, 247, 314, 350, 39521, 395-4, 503, Access Multiplexer (DSLAM) that is part ofa DSL (Digital 370/518, 352, 353, 356; 379/32-01, 84, 93-01, Subscriber Line) system is able to provide synchronous ser379/ 93.04, 9305, 333 vices to end user equipment connected to the DSLAM via a See application file for Complete Search history. DSL link and Customer Premises Equipment (CPE).A sniffer _ device having direct or indirect access to a Primary Reference (56) References Clted Clock (PRC) of the DSL system calculates the phase difference between the PRC and the DSLAM’s Local Timing RefU'S' PATENT DOCUMENTS erence (LTR). The phase difference is sent to the CPEs requir5,440,313 A 8/1995 Osterdock et al. ing accurate reference clock frequency. The CPEs are able to E1 I1iI1_e1;°[1er tet derive the PRC from the phase difference information trans639373613 B1 * 8/2005 Bghgsiail ““““““““ H 370/465 mitted by the sniffer device thus enabling synchronous end 2003/0093703 A1 * 5/2003 Oliver et al. ................ .. 713/400 user eqmpmem OP921110112005/0058149 A1 3/2005 Howe 2005/0265428 A1 12/2005 McCorkle 20 Claims, 11 Drawing Sheets Sniffer DSL V Mapper b» \ 18 Q DSL De-mapper [/15 Di|fDf2EeSrTce Packet \ T A bl Encoder 22 ssem y 11 “/ 2 N 9
