ETSI ETS 300 417-6-1 ed.1 (1998-08)

SLOVENSKI STANDARD
SIST ETS 300 417-6-1 E1:2003
01-december-2003
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Transmission and Multiplexing (TM); Generic requirements of transport functionality of
equipment; Part 6-1: Synchronization layer functions
Ta slovenski standard je istoveten z: ETS 300 417-6-1 Edition 1
ICS:
33.040.20 Prenosni sistem Transmission systems
SIST ETS 300 417-6-1 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 417-6-1 E1:2003

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SIST ETS 300 417-6-1 E1:2003
EUROPEAN ETS 300 417-6-1
TELECOMMUNICATION August 1998
STANDARD
Source: TM Reference: DE/TM-01015-6-1
ICS: 33.020
Key words: transmission, SDH, synchronization
Transmission and Multiplexing (TM);
Generic requirements of transport functionality of equipment;
Part 6-1: Synchronization layer functions
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Internet: secretariat@etsi.fr - http://www.etsi.fr - http://www.etsi.org
Tel.: +33 4 92 94 42 00 - Fax: +33 4 93 65 47 16
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1998. All rights reserved.

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Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Standards Making Support Dept." at the address shown on the title page.

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Contents
Foreword .7
1 Scope .9
2 Normative references.9
3 Definitions, abbreviations and symbols.10
3.1 Definitions .10
3.2 Abbreviations .11
3.3 Symbols and diagrammatic conventions .12
3.4 Introduction .12
4 Synchronization principles.12
4.1 Network synchronization.12
4.2 Synchronization distribution trails.14
4.3 Synchronization interfaces.14
4.3.1 Synchronous Transport Module, level N (STM-N) .15
4.3.2 2 Mbit/s.15
4.3.3 2 MHz .15
4.3.4 34 Mbit/s and 140 Mbit/s with 125 ms frame structure.15
4.4 Clock-Source Quality-Level .15
4.4.1 Clock-Source Quality- Level Definitions .15
4.4.2 Hierarchy of Clock-Sources Quality Level or (CS_QL) .16
4.4.3 Forcing of Clock-Source Quality-Levels.16
4.5 SSM and TM channels.16
4.5.1 SSM and TM message sets .17
4.5.2 SSM and TM code word generation.17
4.5.3 SSM and TM code word interpretation.18
4.6 Selection process.19
4.7 Signal fail .19
4.8 Hold-off time .20
4.9 WTR time.20
4.10 Synchronization source priorities .20
4.11 External commands (EXTCMD) .21
4.11.1 EXTCMDs per nominated synchronization source.21
4.11.1.1 Set_Lockout#p command.21
4.11.1.2 Clear_Lockout#p command .21
4.11.2 EXTCMDs per selection process .21
4.11.2.1 CLR command.21
4.11.2.2 Forced switch #p command.22
4.11.2.3 Manual switch #p command.22
4.12 Automatic reference selection process.22
4.12.1 QL-enabled mode.22
4.12.2 QL-disabled mode.23
4.13 Timing loop prevention.23
4.13.1 Station clock input used as a source for station clock output.23
4.13.2 Between NEs with SEC type clocks .23
4.13.3 Between NEs with a SEC clock and a NE or SASE with a SSU clock and
only one link.24
4.13.3.1 QL/SSM processing supported between SASE and NE.24
4.13.3.2 QL/SSM processing not supported between SASE and
NE.26
4.13.4 Between NEs with a SEC clock and a NE or SASE with a SSU clock and
several links.28
4.14 Delay times for NEs with SEC .28
4.15 Delay times for NEs with SSU or for SASE .29
4.16 Synchronization layer functions .29

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4.17 Overview of the processes performed within the atomic functions. 30
5 Synchronization distribution layer atomic functions . 31
5.1 SD Connection function (SD_C) . 32
5.2 SD Trail Termination (TT) functions. 33
5.2.1 SD TT source function (SD_TT_So) . 33
5.2.2 SD TT sink function (SD_TT_Sk). 34
5.3 SD adaptation functions . 36
5.3.1 SD layer to NS layer SEC quality adaptation source function (SD/NS-
SEC-A_So) . 36
5.3.2 SD layer to NS layer SEC quality adaptation sink function (SD/NS-
SEC_A_Sk). 39
5.3.3 SD layer to NS layer SSU quality adaptation source function (SD/NS-
SSU-A_So) . 40
5.3.4 SD layer to NS layer SSU quality adaptation sink function (SD/NS-
SSU_A_Sk). 40
5.3.5 SD layer to NS layer PRC quality adaptation source function (SD/NS-
PRC-A_So) . 40
5.3.6 SD layer to NS layer adaptation source function (SD/NS_A_So). 40
6 NS layer atomic functions. 41
6.1 NS_connection functions (NS_C) . 42
7 TL to SD layer atomic function. 44
7.1 STM-1 multiplex section adaptation functions. 44
7.1.1 STM-1 multiplex section to sd adaptation source (MS1/SD_A_So) . 44
7.1.2 STM-1 multiplex section to SD adaptation sink (MS1/SD_A_Sk). 45
7.2 STM-4 multiplex section adaptation functions. 46
7.2.1 STM-4 multiplex section to SD adaptation source (MS4/SD_A_So) . 46
7.2.2 STM-4 multiplex section to SD adaptation sink (MS4/SD_A_Sk). 48
7.3 STM-16 multiplex section adaptation functions. 49
7.3.1 STM-16 multiplex section to SD adaptation source (MS16/SD_A_So) . 49
7.3.2 STM-16 multiplex section to SD adaptation sink (MS16/SD_A_Sk). 50
7.4 P31s adaptation functions. 51
7.4.1 P31s to SD adaptation source (P31s/SD_A_So). 51
7.4.2 P31s to SD adaptation sink (P31s/SD_A_Sk) . 53
7.5 P4s adaptation functions. 55
7.5.1 P4s to SD adaptation source (P4s/SD_A_So). 55
7.5.2 P4s to SD adaptation sink (P4s/SD_A_Sk) . 57
7.6 P12s layer adaptation functions . 58
7.6.1 P12s layer adaptation source functions. 58
7.6.1.1 Type 1 P12s to SD adaptation source for station clock
output supporting SSM (P12s/SD-sc-1_A_So) . 58
7.6.1.2 Type 2 P12s to SD adaptation source for station clock
output port not supporting SSM (P12s/SD-sc-2_A_So). 60
7.6.2 P12s layer adaptation sink functions . 61
7.6.2.1 Type 1 P12s to SD adaptation sink for traffic input port
(P12s/SD-tf_A_Sk). 62
7.6.2.2 Type 2 P12s to SD adaptation sink for station clock input
port (P12s/SD-sc_A_Sk). 63
7.7 T12 layer adaptation functions . 64
7.7.1 T12 to SD adaptation source (T12/SD_A_So) . 64
7.7.2 T12 to SD adaptation sink (T12/SD_A_Sk). 66
8 Equipment clock to TLs clock adaptation functions. 67
8.1 STM-N layer . 67
8.1.1 STM-1 Layer Clock (LC) adaptation source (MS1-LC_A_So). 67
8.1.2 STM-4 LC adaptation source (MS4-LC_A_So) . 68
8.1.3 STM-16 LC adaptation source (MS16-LC_A_So) . 69
8.2 VC layers. 70
8.2.1 VC-4 LC adaptation source (S4-LC_A_So). 70
8.2.2 VC-3 LC adaptation source (S3-LC_A_So). 71
8.2.3 VC-2 LC adaptation source (S2-LC_A_So). 72

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8.2.4 VC-12 LC adaptation source (S12-LC_A_So).73
8.2.5 VC-11 LC adaptation source (S11-LC_A_So).74
8.3 Pxx layers .75
8.3.1 P4s LC adaptation source (P4s-LC_A_So).75
8.3.2 P31s LC adaptation source (P31s-LC_A_So).76
8.3.3 P12s LC adaptation source (P12s-LC_A_So).77
8.4 T12 layer .78
8.4.1 T12 LC adaptation source (T12-LC_A_So).78
Annex A (normative): Synchronization selection process .79
Annex B (informative): TL models for synchronization information.90
Annex C (informative): Examples of synchronization functionality in the NE .93
Annex D (informative): Delay time allocation .96
D.1 Delay and processing times for the synchronization selection process .96
D.2 Non switching message delay T .97
NSM
D.3 Switching message delay T .97
SM
D.4 Holdover message delay T .98
HM
D.5 Wait to restore time T .99
WTR
Annex E (informative): Overview of inputs/outputs to the atomic functions.100
History.101

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Foreword
This European Telecommunication Standard (ETS) has been produced by the Transmission and
Multiplexing (TM) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This ETS has been produced in order to provide inter-vendor and inter-operator compatibility of
Synchronous Digital Hierarchy (SDH) equipment.
This ETS consists of 8 parts as follows:
Part 1: "Generic processes and performance" (ETS 300 417-1-1 [1]);
Part 2: "SDH and PDH physical section layer functions" (ETS 300 417-2-1 [6]);
Part 3: "STM-N regenerator and multiplex section layer functions" (ETS 300 417-3-1 [7]);
Part 4: "SDH path layer functions" (ETS 300 417-4-1 [8]);
Part 5: "PDH path layer functions" (ETS 300 417-5-1 [9]);
Part 6: "Synchronization layer functions" (ETS 300 417-6-1);
Part 7: "Auxiliary layer functions" (ETS 300 417-7-1);
Part 8: "Compound and major compound functions" (ETS 300 417-8-1).
Transposition dates
Date of adoption of this ETS: 24 July 1998
Date of latest announcement of this ETS (doa): 30 November 1998
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 May 1999
Date of withdrawal of any conflicting National Standard (dow): 31 May 1999

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1 Scope
This ETS specifies a library of basic Synchronization Distribution (SD) building blocks, referred to as
"atomic functions" and a set of rules by which they are combined in order to describe a digital transmission
equipment. The library defined in this ETS forms part of the set of libraries defined in ETS 300 417 series.
The library comprises the functional building blocks needed to completely specify the generic functional
structure of the European digital transmission hierarchy. Equipment that is compliant with this ETS should
be describable as an interconnection of a subset of these functional blocks contained within this ETS. The
interconnection of these blocks should obey the combination rules given in ETS 300 417. The generic
functionality is described in ETS 300 417-1-1 [1].
This ETS assumes that there are only two types of Synchronization Supply Units (SSUs), transit and local,
as currently defined in ITU-T Recommendation G.812 [18]. However, STC TM3 has approved in
September 1996 a new SSU with enhanced characteristics. The inclusion of such an SSU in this ETS is
for further study.
This ETS does not specify the atomic functions that are specific to SSU and Primary Reference Clock
(PRC); the Synchronization Status Message (SSM) selection algorithm specified in the present document
applies only to SEC’s.
2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references subsequent amendments to, or revisions of, any of these publications
apply to this ETS only when incorporated in it by amendments or revisions. For undated references the
latest edition of the publication referred to applies.
[1] ETS 300 417-1-1 (1996): "Transmission and Multiplexing (TM); Generic
functional requirements for Synchronous Digital Hierarchy (SDH) equipment;
Part 1-1: Generic processes and performance".
[2] ETS 300 147: "Transmission and Multiplexing (TM); Synchronous Digital
Hierarchy (SDH); Multiplexing structure".
[3] ETS 300 166 (1993): "Transmission and Multiplexing (TM); Physical and
electrical characteristics of hierarchical digital interfaces for equipment using the
2 048 kbit/s - based plesiochronous or synchronous digital hierarchies".
[4] ITU-T Recommendation G.707 (1996): "Network node interface for the
synchronous digital hierarchy (SDH)".
[5] ITU-T Recommendation G.783: "Characteristics of synchronous digital hierarchy
(SDH) equipment functional blocks".
[6] ETS 300 417-2-1: "Transmission and Multiplexing (TM); Generic requirements
of transport functionality of equipment; Part 2-1: Synchronous Digital Hierarchy
(SDH) and Plesiochronous Digital Hierarchy (PDH) physical section layer
functions".
[7] ETS 300 417-3-1: "Transmission and Multiplexing (TM); Generic requirements
of transport functionality of equipment; Part 3-1: Synchronous Transport
Module-N (STM-N) regenerator and multiplex section layer functions".
[8] ETS 300 417-4-1: "Transmission and Multiplexing (TM); Generic requirements
of transport functionality of equipment; Part 4-1: Synchronous Digital Hierarchy
(SDH) path layer functions".
[9] ETS 300 417-5-1: "Transmission and Multiplexing (TM); Generic requirements
of transport functionality of equipment; Part 5-1: Plesiochronous Digital
Hierarchy (PDH) path layer functions".

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[10] ETS 300 462-2: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 2: Synchronization network architecture".
[11] ETS 300 462-4: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 4: Timing characteristics of slave clocks suitable
for synchronization supply to Synchronous Digital Hierarchy (SDH) and
Plesiochronous Digital Hierarchy (PDH) equipment".
[12] ETS 300 462-5: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 5: Timing characteristics of slave clocks suitable
for operation in Synchronous Digital Hierarchy (SDH) equipment".
[13] ETS 300 462-6: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 6: Timing characteristics of primary reference
clocks".
[14] ITU-T Recommendation G.704 (1995): "Synchronous frame structures used at
1 544, 6 312, 2 048, 8 488 and 44 736 kbit/s hierarchical levels".
[15] ETS 300 337 (1996): "Transmission and Multiplexing (TM); Generic frame
structures for the transport of various signals (including Asynchronous Transfer
Mode (ATM) cells and Synchronous Digital Hierarchy (SDH) elements) at the
ITU-T Recommendation G.702 hierarchical rates of 2 048 kbit/s, 34 368 kbit/s
and 139 264 kbit/s".
[16] ETS 300 337 (1995): "Transmission and Multiplexing (TM); Generic frame
structures for the transport of various signals (including Asynchronous Transfer
Mode (ATM) cells and Synchronous Digital Hierarchy (SDH) elements) at the
ITU-T Recommendation G.702 hierarchical rates of 2 048 kbit/s, 34 368 kbit/s
and 139 264 kbit/s".
[17] ITU-T Recommendation G.811 (1988): "Timing requirements at the outputs of
primary reference clocks suitable for plesiochronous operation of international
digital links".
[18] ITU-T Recommendation G.812 (1988.): "Timing requirements at the outputs of
slave clocks suitable for plesiochronous operation of international digital links".
[19] ITU-T Recommendation G.813 (1996): "Timing characteristics of SDH
equipment slave clocks (SEC)".
[20] ETS 300 167: "Transmission and Multiplexing (TM); Functional characteristics of
2 048 kbit/s interfaces".
[21] ETS 300 462-1: "Transmission and Multiplexing (TM); Generic requirements for
synchronization networks; Part 1: Definitions and terminology for
synchronization networks".
3 Definitions, abbreviations and symbols
3.1 Definitions
For the purposes of this ETS, the following definition applies:
timing loop: This is a network condition where a slave clock providing synchronization becomes locked to
its own timing signal. It is generally created when the slave clock Timing Information (TI) is looped back to
its own input, either directly or via other network equipments. Timing loops should be prevented in
networks by careful network design.
QL minimum: QL_minimum is a configurable parameter used in the squelching of clock output signals. If
the Quality Level (QL) of the signal used to derive the output falls below QL_Minimum then the output will
be squelched (cut-off or set to Alarm Indication Signal (AIS)).

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Clock-Source Quality-Level: The clock-source quality-level of a SDH Equipment Clock (SEC) or Stand
Alone Synchronization Equipment (SASE) is defined as the grade of clock to which it is ultimately
traceable; i.e. the grade-of-clock to which it is synchronized directly or indirectly via a chain of SEC’s, and
SASE’s however long this chain of clocks is. For example, the clock-source quality-level may be a PRC
complying with ETS 300 462-6 [13], or it may be a Slave Clock in holdover-mode, complying with
ETS 300 462-4 [11], or a ETS 300 462-5 [12] Clock in holdover or free-run.
The clock-source quality-level is essentially, therefore, an indication only of the long-term accuracy of the
Network Element (NE) Clock.
Station Clock: This is a node clock as defined in ETS 300 462-1 [21].
The functional definitions are given in ETS 300 417-1-1 [1].
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AI Adaptation Information
AIS Alarm Indication Signal
AP Access Point
CI Characteristic Information
CK timing information - Clock signal
CLR Clear
CP Connection Point
CS timing information - Clock Source
CSid Clock Source identifier
DNU Do Not Use
ES1 STM-1 Electrical Section layer
EXTCMD External Command
FS timing information - Frame Start
FSw Forced Switch
HO Hold Over mode
HO Hold Off time
ID IDentifier
INVx INValid x
LC Layer Clock
LO Lock Out
LO Locked mode
LOS Loss Of Signal
LSB Least Significant Bit
LTI Loss of Timing Information
MA Maintenance and Adaptation
MI Management Information
MON MONitored
MFP MultiFrame Present
MFS MultiFrame Start
MS Multiplex Section
MSB Most Significant Bit
MSw Manual Switch
MTIE Maximum Time Interval Error
NE Network Element
NS Network Synchronization
NSUPP Not supported
OSn STM-N Optical Section layer
P12s 2 048 kbit/s PDH path layer with synchronous 125 ms frame structure according
to ETS 300 167 [20]
P31s 34 368 kbit/s PDH path layer with synchronous 125 ms frame structure
according to ETS 300 337 [15]
P4s 139 264 kbit/s PDH path layer with synchronous 125 ms frame structure
according to ETS 300 337 [15]
PDH Plesiochronous Digital Hierarchy
PRC Primary Reference Clock

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QL Quality Level
RI Remote Information
RSn STM-N Regenerator Section layer
SASE Stand Alone Synchronization Equipment
SD Synchronization Distribution
SDH Synchronous Digital Hierarchy
SDL Specification and Description Language
SEC SDH Equipment Clock
SF Signal Fail
SQLCH Squelch
SSF Server Signal Fail
SSM Synchronization Status Message
SSU Synchronization Supply Unit
SSUL Local SSU
SSUT Transit SSU
STM-N Synchronous Transport Module, level N
Sk Sink
So Source
TCP Termination Connection Point
TDEV Time DEViation
TI Timing Information
TL Transport Layer
TM Timing Marker
TT Trail Termination
TSF Trail Signal Fail
UNC UNConnected
VC-n Virtual Container, level n
WTR Wait to Restore
3.3 Symbols and diagrammatic conventions
The symbols and diagrammatic conventions are given in ETS 300 417-1-1 [1].
3.4 Introduction
This subclause defines the atomic functions that are part of the 2 synchronization layers, the SD layer and
the Network Synchronization (NS) layer. It also defines some atomic functions, part of the Transport Layer
(TL), which are related with synchronization.
These functions describe the synchronization of SDH NEs and how SDH NEs are involved in NS.
4 Synchronization principles
4.1 Network synchronization
Synchronization network architecture is specified in ETS 300 462-2 [10].
Synchronization information is transmitted through the network via synchronization network connections.
These synchronization network connections can transport different synchronization levels. Each
synchronization network connection is provided by one or more synchronization link connections, each
supported by a synchronized primary or secondary rate Plesiochronous Digital Hierarchy (PDH) trail or
SDH multiplex section trail (see clause 5 of ETS 300 462-2 [10]).
Some of these synchronized primary or secondary rate PDH trail or SDH multiplex section trail signals
contain a communication channel, the SSM or the Timing Marker (TM) transporting a quality Identifier
(ID). This QL ID can be used to select the highest synchronization level incoming reference signal from a
set of nominated synchronization references available at the NE.
Synchronization network connections are uni-directional and generally point to multipoint.
ETS 300 462-2 [10] specifies a master-slave synchronization technique for synchronizing SDH networks
(see subclause 4.1 of ETS 300 462-
...