Standards
These are the main Standards which relate to synchronisation of telecom networks. The move to next generation network (NGN) technology has meant that new Standards must evolve. ITU Study Group 15/Q13 is working on a number of new Standards for packet based network synchronisation as are the IEEE with a new PTP Standard - 1588-2008 and the IETF with the TICTOC BOF. If you have any questions about any of these standards, please give us a call, we are monitoring developments very closely and we maintain contact with key editors and working groups.
ITU-T Standards & Recommendations
Chronos is an associate member of the ITU-T Study Group 15, Question 13 - Network Synchronisation & Time Distribution Performance.
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Standard |
Publication Date |
Description |
G.703 |
2001-11 |
"Physical/electrical characteristics of hierarchical digital interfaces". Defines the "G.703-13" 2048 kHz analogue synchronisation signal or "G.703-9" 2048 kbit/s digital synchronisation signals presented as either 120 ohms balanced or 75 ohms unbalanced. Equivalent to EN 300 166 |
G.704 |
1998-10 |
Defines the frame structure/functional characteristics of interfaces associated with network nodes, synchronous digital multiplex equipment, PCM multiplexing equipment (i.e. 1544, 2048, 8448 kbit/s, etc.). |
G.709 |
2001-02 |
Network node interfaces for the Optical Transport Network (OTN) |
G.783 |
2000-10 |
Characteristics of Synchronous Digital Hierarchy (SDH) Equipment Functional Blocks |
G.803 |
2000-03 |
"Architecture of transport networks based on the synchronous digital hierarchy (SDH)".This defines the 20xSEC and 10xSSU rule in SDH networks. Equivalent to EN 300 462-2-1 |
G.810 |
1996-08 |
"Definitions and terminology for synchronisation networks" Equivalent to ETSI EN 300 462-1-1. |
G.811 |
1997-09 |
"Timing requirements of primary reference clocks"Defines requirements of Level 1 Primary Reference Clock systems. Equivalent to ETSI EN 300 462-6-1. |
G.812 |
1998-06 |
"Timing requirements of slave clocks suitable for use as node clocks in synchronisation networks"Defines requirements of slave clocks (Level 2 & 3). Equivalent to ETSI EN 300 462-4-1 and EN 300 462-7-1. |
G.813 |
2003-03 |
"Timing characteristics of SDH equipment slave clocks (SEC)." Equivalent to ETSI EN 300 462-5-1. |
G.822 |
1988-11 |
"Controlled Slip Rate Objectives on an International Digital Connection" Defines the "1 slip in 72 days" requirement |
G.823 |
2000-03 |
"The control of jitter and wander within digital networks which are based on the 2.048 kbit/s hierarchy”. Defines control of jitter and wander in digital networks based on the 2048 kbit/s hierarchy. Equivalent to EN 302 084 |
G.824 |
2000-03 |
"The control of jitter and wander within digital networks which are based on the 1,544 kbit/s hierarchy". Defines control of jitter and wander in digital networks based on the 1544 kbit/s hierarchy. |
G.825 |
2000-03 |
"The control of jitter and wander within digital networks which are based on the synchronous digital hierarchy (SDH)". Defines control of jitter and wander in digital networks based on the synchronous digital hierarchy (SDH). |
G.8251 |
2001-11 |
The Control of Jitter and Wander Within the Optical Transport Network (OTN) This will be the next important standard as far as synchronisation is concerned to emerge from ITU-T Study Group 15 WP3 Network Synchronisation and Time Distribution Performance. |
| G.8261 | 2006-05 | Timing and synchronization aspects in packet networks. Proposes Jitter and Wander limits as portions of the G.823 Limits to be assigned to Circuit Emulation Islands. Most revolutionary proposal is for Synchronous Ethernet, Making the physical line clock of Ethernet lockable to an External reference. Also proposes standard test scenario CES equipment. |
| G.8262 | 2009-10 | Timing characteristics of synchronous ethernet equipment slave clock (EEC) Contains clock specifications for Ethernet Equipment Clocks analagous to the SDH specifications in G.811/812/813 G.8264 2008-10 Distribution of timing information through packet networks Contains functional models of packet network clocks and the logical flows of timing information through the network. |
O.171 |
1997-04 |
"Timing jitter and wander measuring equipment for digital systems which are based on the plesiochronous digital hierarchy (PDH)." |
O.172 |
1999-03 |
"Jitter and wander measuring equipment for digital systems which are based on the synchronous digital hierarchy (SDH)". |
| O.173 | 2003-02 | "Jitter measuring equipment for digital systems which are based on the Optical Transport Network (OTN)." |
| 0.174 | 2009-11 | "Jitter and wander measuring equipment for a synchronous packet network (SyncE)." |
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ETSI Standards & Other Publications
Click on the logo to go to the ETSI web site. Publication downloads are free. Since most ETSI and ITU Synchronisation Standards are pretty well identical. Get them here, it's cheaper!
Standard |
Publication Date |
Description |
TR 101 685 v1.1.1 |
1999-08 |
"Transmission and Multiplexing (TM); Timing and Synchronisation aspects of Asynchronous Transfer Mode (ATM) networks" |
2001-04 |
"GSM: Digital cellular telecommunication system (Phase 2+); Radio subsystem synchronisation (GSM 05.10)". This is the standard which defines the RF stability of GSM basestations as 5 x 10-8. |
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| TS 125 105 v4.1.0 |
2001-06 |
Universal Mobile Telecommunications System (UMTS); |
| TS 125 402 v4.1.0 |
2001-06 |
Universal Mobile Telecommunications System (UMTS); |
| EG 201 793 v1.1.1 . |
2000-10 |
"Transmission and Multiplexing (TM); Synchronisation Network Engineering" This is an ETSI Guide rather than a Standard, but is one of the better documents and captures a lot of the key issues |
| ETS 300 147 |
1996 |
"Transmission and Multiplexing (TM); Synchronous Digital Hierarchy(SDH) Multiplexing Structure". |
| ETS 300 166 |
1993-08 |
"Physical and electrical characteristics of hierarchical digital interfaces for equipment using the 2,048 kbit/s-based plesiochronous or synchronous digital hierarchies". Equivalent to G.703. |
| EN 300 417-6-1 v1.1.3 |
1999-05 |
"Transmission and Multiplexing (TM); Generic requirements of transport functionality of equipment; Part 6-1: Synchronisation layer functions" This is one of a family of documents that has been produced in order to provide inter-vendor and inter-operator compatibility of Synchronous Digital Hierarchy (SDH) equipment. |
| EN 300 462-x Series |
"Transmission and Multiplexing (TM); Generic requirements for synchronisation networks" The main family of synchronisation definitions for SEC's, SSU's and PRC's. Equivalent to G.811, G.812, G.813. See below for the complete series |
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| EN 300 462-1-1 v1.1.1 |
1998-05 |
"Part 1-1: Definitions and terminology for synchronisation networks"Equivalent to G.810 |
| EN 300 462-2-1 v1.1.2 |
1999-08 |
"Part 2-1: synchronisation network architecture" This defines the 20xSEC and 10xSSU rule in SDH networks. Equivalent to G.803. |
| EN 300 462-3-1 v1.1.1 |
1998-05 |
"Part 3-1: The control of jitter and wander within synchronisation networks". |
| EN 300 462-4-1 v1.1.1 |
1998-05 |
"Part 4-1: Timing characteristics of slave clocks suitable for synchronisation supply to Synchronous Digital Hierarchy (SDH) and Plesiochronous Digital Hierarchy (PDH) equipment". The main ETSI Standard for specifying SSU/SASE's in terms of holdover and jitter/wander. Equivalent to G.812. |
| EN 300 462-5-1 v1.1.2 |
1998-05 |
"Part 5-1: Timing characteristics of slave clocks suitable for operation in Synchronous Digital Hierarchy (SDH) equipment" The main ETSI Standard for specifying SEC's in terms of holdover and jitter/wander. Equivalent to G.813. |
| EN 300 462-6-1 v1.1.1 |
1998-05 |
"Part 6-1: Timing characteristics of primary reference clocks" The main ETSI Standard for specifying PRC's in terms of holdover and jitter/wander. Equivalent to G.811. |
| EN 300 462-7-1 v1.1.2 |
2001-06 |
"Part 7-1:Timing characteristics of slave clocks suitable for synchronisation supply to equipment in local node applications". The main ETSI Standard for specifying Local SSU/SASE's in terms of holdover and jitter/wander. Equivalent to G.812. |
| TS 100 912 v8.8.0 |
2001-04 |
"GSM: Digital cellular telecommunication system (Phase 2+); Radio subsystem synchronisation (GSM 05.10)". This is the standard which defines the RF stability of GSM base stations as 5 x 10-8 Same as TS 145 010 (above) |
| EN 302 084 v1.1.1 |
2000-02 |
"Transmission and Multiplexing (TM); The control of jitter and wander in transport networks" Equivalent to G.823 & G.825 |
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IEEE
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| IEC 61588 | 2004-09 | IEEE1588 : Precision clock synchronization protocol for networked measurement and control systems |
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