SIST ETS 300 337 E2:2003

SLOVENSKI STANDARD
01-december-2003
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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
Ta slovenski standard je istoveten z: ETS 300 337 Edition 2
ICS:
33.040.20 Prenosni sistem Transmission systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 337
TELECOMMUNICATION June 1997
STANDARD Second Edition
Source: ETSI TC-TM Reference: RE/TM-03056
ICS: 33.020
Key words: Transmission, ATM, SDH, transport
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
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
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariat@etsi.fr
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 1997. All rights reserved.

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ETS 300 337: June 1997
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 Editing and Committee Support Dept." at the address shown on the title page.

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ETS 300 337: June 1997
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .7
3.1 Definitions .7
3.2 Abbreviations .8
4 Frame structure at 2 048 kbit/s .8
4.1 Basic frame structure.8
4.2 Support of ATM cells in 2 048 kbit/s .8
5 Frame structure at 34 368 kbit/s .9
5.1 Basic frame structure.9
5.1.1 General.9
5.1.2 Path overhead .10
5.2 Support of ATM cells in 34 368 kbit/s .12
5.3 Support of 14 SDH TU-12s in 34 368 kbit/s.12
5.3.1 Coding of multiframe indicator for TU multiframe indication .13
6 Frame structure at 139 264 kbit/s .14
6.1 Basic frame structure.14
6.1.1 General.14
6.1.2 Path overhead .15
6.2 Support of ATM cells in 139 264 kbit/s .17
6.3 Support of SDH elements in 139 264 kbit/s.18
6.3.1 Coding of multiframe indicator for TU multiframe indication .18
6.3.2 Support of 20 x TUG-2 .18
6.3.3 Support of 2 x TUG-3 and 5 x TUG-2 .18
7 Conformance testing .20
Annex A (informative): Functions specific to the support of ATM cells.21
A.1 Cell rate adaptation .21
A.2 Header Error Control (HEC) generation.21
A.3 Cell delineation.21
A.4 Cell header verification and extraction .21
Annex B (informative): Bibliography.22
History.23

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ETS 300 337: June 1997
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ETS 300 337: June 1997
Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the
Transmission and Multiplexing (TM) Technical Committee of the European Telecommunications
Standards Institute (ETSI).
This ETS specifies generic frame structures for the transport of various signals at the
ITU-T Recommendation G.702 [1] hierarchical rates of 2 048 kbit/s, 34 368 kbit/s and 139 264 kbit/s. The
support of Asynchronous Transfer Mode (ATM) cells and Synchronous Digital Hierarchy (SDH) Tributary
Units (TUs) in the Plesiochronous Digital Hierarchy (PDH) bit rates is also covered in this ETS.
This ETS takes into account the recommendations given in ITU-T Recommendation G.804 (annex B.2)
and G.832 (annex B.3) - see annex B (Bibliography) for details.
Transposition dates
Date of adoption: 7 March 1997
Date of latest announcement of this ETS (doa): 30 September 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 March 1998
Date of withdrawal of any conflicting National Standard (dow): 31 March 1998

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ETS 300 337: June 1997
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ETS 300 337: June 1997
1 Scope
This second edition European Telecommunication Standard (ETS) specifies generic frame structures for
the transport of various signals at the ITU-T Recommendation G.702 [1] hierarchical rates of 2 048 kbit/s,
34 368 kbit/s and 139 264 kbit/s. The support of Asynchronous Transfer Mode (ATM) cells and
Synchronous Digital Hierarchy (SDH) Tributary Units (TUs) in the Plesiochronous Digital Hierarchy (PDH)
bit rates is covered in this ETS. Functions specific to the support of ATM cells performed in the transmitter
and receiver are not part of this interface standard but are given for information in annex A.
2 Normative references
This ETS incorporates by dated and 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 amendment or revision. For undated references the latest
edition of the publication referred to applies.
[1] ITU-T Recommendation G.702 (1988): "Digital hierarchy bit rates".
[2] ETS 300 167: "Transmission and Multiplexing (TM); Functional characteristics of
2 048 kbit/s interfaces".
[3] ETS 300 147 (1995): "Transmission and Multiplexing (TM); Synchronous digital
hierarchy; Multiplexing structure".
[4] ITU-T Recommendation G.831 (1996): "Management capabilities of transport
networks based on the Synchronous Digital Hierarchy (SDH)".
[5] ITU-T Recommendation T.50 (1992): "Information technology - 7-bit coded
character set for information interchange".
[6] ITU-T Recommendation G.707 (1995): "Synchronous Digital Hierarchy (SDH) bit
rates".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
idle cell: A cell which is inserted and extracted by the adaptation function between the ATM virtual path
layer network and the PDH path layer network in order to adapt the cell flow rate to the available payload
capacity of the PDH path used.
valid cell: A cell whose header is declared by the cell Header Error Control (HEC) process to be free of
errors.
NOTE: The order of transmission of information in all diagrams in this ETS is first from left to
right and then top to bottom. Within each byte the most significant bit is transmitted
first. The most significant bit (bit 1) is illustrated at the left of all diagrams.

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ETS 300 337: June 1997
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
ATM Asynchronous Transfer Mode
BIP-8 Bit Interleaved Parity - 8
CRC Cyclic Redundancy Check
EM Error Monitoring
FA Frame Alignment
GC General purpose Communication
HEC Header Error Control
IEC Incoming Error Count
MSB Most Significant Bit
MA Maintenance and Adaptation
NR Network operatoR
OAM Operations, Administration and Maintenance
PDH Plesiochronous Digital Hierarchy
RDI Remote Defect Indication
REI Remote Error Indication
SDH Synchronous Digital Hierarchy
SSM Synchronization Status Message
TR TRail trace
TS Time Slot
TTI Trail Trace Identifier
TU Tributary Unit
TUG-n Tributary Unit Group of level n
TU-x Tributary Unit - x
4 Frame structure at 2 048 kbit/s
4.1 Basic frame structure
The basic frame structure at 2 048 kbit/s as described in ETS 300 167 [2] shall be used. This comprises a
generic path overhead, a signalling channel and a generic payload capacity of 1 920 kbit/s.
4.2 Support of ATM cells in 2 048 kbit/s
Valid or idle cells are supported in bits 9 to 128 and bits 137 to 256 of the 2 048 kbit/s frame with the octet
structure of the cells aligned with the octet structure of the frame (see figure 1). Bits 129 to 136
correspond to Time Slot 16 (TS 16) in an octet structured frame and are reserved for future use. Valid or
idle cells occupy the whole of the payload and a cell can cross a 125 μs frame boundary. The ATM cell
payload is scrambled using a self-synchronizing scrambler with the generator polynomial x + 1. Cell
payload field scrambling is required to provide security against false cell delineation and to prevent the cell
payload replicating the 2 048 kbit/s frame alignment word.
TS0 TS 16
bits 1-8 bits 129-136
path overhead reserved for signalling
9 bit num bers 128 137 bit num bers 256
Figure 1: Frame structure at 2 048 kbit/s

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ETS 300 337: June 1997
5 Frame structure at 34 368 kbit/s
5.1 Basic frame structure
This frame structure is intended to be used in a generic way. When implementing this frame structure,
care should be taken to ensure that the performance of the frame alignment mechanism is not
compromised by the payload content.
5.1.1 General
The basic frame structure at 34 368 kbit/s comprises 7 octets of generic path overhead and 530 octets of
payload capacity per 125 μs as shown in figure 2.
59 columns
FA1 FA2
EM
TR
MA
530 octets
r
payload
o
NR
w
s
GC
Figure 2: Frame structure at 34 368 kbit/s

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ETS 300 337: June 1997
5.1.2 Path overhead
The values and allocation of the path overhead are shown in figure 3 and are described below.
1 1 1 0110 0 0 1 0 1 0 0 0
FA1 1 FA2
BIP-8
EM
TRAIL TRACE
TR
MA MFI SSM
Payload T .ype
RDI
REI
NR
NR
GC
GC
MFI = Multiframe Indicator
SSM = Synchronization Status Message
Figure 3: Path overhead at 34 368 kbit/s
FA1/FA2: Frame Alignment signal, this has the same pattern as defined in clause 7 of
ETS 300 147 [3].
EM: Error Monitoring, BIP-8. One byte is allocated for path error monitoring. This
function shall be a BIP-8 code using even parity. The path BIP-8 is calculated
over all bits of the previous 125 μs frame. The computed BIP-8 is placed in the
EM byte of the current 125 μs frame.
TR: Trail trace. This byte is used to transmit repetitively a trail access point identifier
so that a trail receiving terminal can verify its continued connection to the
intended transmitter. The trail access point identifier shall use the access point
identifier format as defined in section 3 of ITU-T Recommendation G.831 [4].
Trail access point Identifier format:
A 16-byte frame is defined for the transmission of the access point identifier. The first byte of the string is
a frame start marker and includes the result of a CRC-7 calculation over the previous frame. The following
15 bytes are used for the transport of 15 ITU-T Recommendation T.50 [5] characters required for the
access point identifier. The 16-byte frame is given below:
1C CCCCCC : frame start marker;
1 7
0XXXXXXX: byte 2;
0XXXXXXX: byte 16;
0XXXXXXX: ITU-T Recommendation T.50 [5] character;
C CCCCCC : result of the CRC-7 calculation over the previous frame.
1 7
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ETS 300 337: June 1997
The description of the CRC-7 calculation is given below.
Multiplication/division process
A particular CRC-7 word is the remainder after multiplication by x and then division (modulo 2) by the
7 3
generator polynomial x + x + 1, of the polynomial representation of the previous Trail Trace Identifier
(TTI) multiframe.
When representing the contents of the block as a polynomial, the first bit in the block, (i.e. byte 1, bit 1)
should be taken as being the most significant bit. Similarly, C is defined to be the most significant bit of
the remainder and C to be the least significant bit of the remainder.
Encoding procedure
Contrary to e.g. the CRC-4 procedure in 2 Mbit/s signals, the CRC-7 word is static because the data is
static (the TTI represents the source address). This means that the CRC-7 checksum can be calculated a
priori
...