SIST ETS 300 419:1999
(Main)Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines (D2048S); Connection characteristics
Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines (D2048S); Connection characteristics
Specification of the performance requirement for the connection through the public network, including test procedures for compliance
Poslovne telekomunikacije (BTC) - Digitalni zakupljeni vodi za prenosno hitrost 2 048 kbit/s in za strukturirane signale (D2048S) - Prenosne značilnosti
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-1999
3RVORYQHWHOHNRPXQLNDFLMH %7& 'LJLWDOQL]DNXSOMHQLYRGL]DSUHQRVQRKLWURVW
NELWVLQ]DVWUXNWXULUDQHVLJQDOH '6 3UHQRVQH]QDþLOQRVWL
Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased lines
(D2048S); Connection characteristics
Ta slovenski standard je istoveten z: ETS 300 419 Edition 1
ICS:
33.040.50 Vodi, zveze in tokokrogi Lines, connections and
circuits
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN ETS 300 419
TELECOMMUNICATION November 1995
STANDARD
Source: ETSI TC-BTC Reference: DE/BTC-02022
ICS: 33.040.40
ONP, leased line, D2048S, connection
Key words:
Business TeleCommunications (BTC);
2 048 kbit/s digital structured leased lines (D2048S);
Connection characteristics
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 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 1995. All rights reserved.
New presentation - see History box
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ETS 300 419: November 1995
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 300 419: November 1995
Contents
Foreword .5
Introduction.5
1 Scope .7
2 Normative references.7
3 Definitions and abbreviations .8
3.1 Definitions .8
3.2 Abbreviations .9
4 Requirements.10
4.1 Attributes.10
4.1.1 Transfer rate.11
4.1.1.1 Leased line timing.11
4.1.1.2 Information transfer rate .11
4.1.2 Information transfer susceptance.11
4.1.3 Structure.12
4.1.3.1 CRC-4.12
4.1.3.2 Use of the E-bits .12
4.1.3.3 Frame synchronization and data transmission capability .12
4.1.3.3.1 Multiframe alignment .13
4.1.3.4 Use of the A-bit.13
4.1.3.5 Use of the S bits .13
a
4.1.4 Establishment of connection .13
4.1.5 Symmetry .13
4.1.6 Connection configuration.13
4.1.7 Network performance.13
4.1.7.1 Transmission delay.13
4.1.7.2 Jitter.14
4.1.7.2.1 Jitter tolerance at the network input
port.14
4.1.7.2.2 Maximum jitter at the network output
port.15
4.1.7.3 Controlled slip.15
4.1.7.4 Error.16
4.1.7.4.1 Bringing Into Service (BIS) limits .16
4.1.7.4.2 Performance level.16
4.1.7.5 Availability.16
Annex A (normative): Test methods.17
A.1 General.17
A.1.1 Equipment connection .17
A.1.2 Sequence of performing the tests.17
A.2 Test methods .17
A.2.1 Information transfer rate, susceptance and symmetry .17
A.2.2 Delay.18
A.2.3 Jitter .19
A.2.4 Error and slip.21
A.2.5.1 Output structure and CRC-4 generation.21
A.2.5.2 Use of the E-bits.22
A.2.5.3 Frame synchronization and data transmission capability.23
A.2.5.4 Multiframe alignment.24
Annex B (normative): Definition of frame structure .26
B.1 Frame structure.26
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ETS 300 419: November 1995
B.2 CRC-4. 26
B.2.1 CRC-4 generation . 26
B.2.2 CRC-4 monitoring . 27
Annex C (informative): Derivation of error performance limits . 28
C.1 Introduction. 28
C.2 Reference connections. 28
C.2.1 Terrestrial connection. 28
C.2.2 Satellite connection . 29
C.3 Error performance objectives . 29
C.4 Long term error performance . 30
Annex D (informative): Availability . 31
D.1 General. 31
D.1.1 Unavailability . 31
D.1.2 Outage intensity . 31
D.1.3 Mean time between failures . 31
D.1.4 Mean time to restore service. 31
D.2 Recommendations. 31
Annex E (informative): Bibliography . 32
History. 33
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ETS 300 419: November 1995
Foreword
This European Telecommunication Standard (ETS) has been produced by the Business
TeleCommunications (BTC) Technical Committee of the European Telecommunications Standards
Institute (ETSI).
This ETS resulted from a mandate from the Commission of the European Community (CEC) to provide
harmonized standards for support of the Directive on Open Network Provision (ONP) of leased lines
(92/44/EEC).
There are two other standards directly related to this ETS:
- ETS 300 418: "Business TeleCommunications (BTC); 2 048 kbit/s digital unstructured and
structured leased lines (D2048U and D2048S); Network interface presentation";
- ETS 300 420: "Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased line
(D2048S); Terminal equipment interface".
This ETS is based on information from ITU-T Recommendations and ETSI publications and the relevant
documents are quoted where appropriate.
Transposition dates
Date of adoption of this ETS 17 November 1995
Date of latest announcement of this ETS (doa): 28 February 1996
Date of latest publication of new National Standard 31 August 1996
or endorsement of this ETS (dop/e):
Date of withdrawal of any conflicting National Standard (dow): 31 August 1996
Introduction
The Council Directive on the application of ONP to leased lines (92/44/EEC) concerns the harmonization
of conditions for open and efficient access to, and use of, the leased lines provided over public
telecommunications networks, and the availability throughout the European Union (EU) of a minimum set
of leased lines with harmonized technical characteristics.
The consequence of the Directive is that telecommunications organizations within the EU shall make
available a set of leased lines between points in these countries with specified connection characteristics
and specified interfaces. Under the Second Phase Directive (91/263/EEC), terminal equipment for
connection to these leased lines will be required to fulfil certain essential requirements.
CCITT Recommendation I.340 for Integrated Services Digital Network (ISDN) connection types is used as
a basis for the connection characteristics. ETS 300 167 and CCITT Recommendations G.704 and G.706
are used as the basis for the structure.
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Blank page
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1 Scope
This ETS specifies the technical requirements and test principles for connection characteristics of Open
Network Provision (ONP) 2 048 kbit/s digital structured leased lines. The leased line operates at
2 048 kbit/s and provides an information transmission capability, without restriction on binary content, of
1 984 kbit/s. The remaining 64 kbit/s provides a 8 kHz framing structure in accordance with ETS 300 167
and CCITT Recommendations G.704 and G.706.
A connection is presented via interfaces at Network Termination Points (NTPs) and includes any
equipment that may provide the NTP. Signals between terminal equipments are subject to impairments
during their transfer over the connection. The limits to these impairments are stated in this ETS. Together
with the companion standard, ETS 300 418 defining the network interface presentation, this ETS
describes the technical characteristics of the leased line service offered to the user.
The tests specified in this ETS cannot be carried out by the leased line provider, while the leased line is in
service, i.e. carrying users' traffic. Thus the tests are designed for bringing into and returning into service,
although there is no obligation to perform these tests each time a leased line is brought into or returned
into service. However, because the connection is structured, the error performance may be monitored by
the leased line provider while the line is in service.
This ETS is applicable for leased lines, including part time leased lines, for which the establishment or
release does not require any protocol exchange or other intervention at the NTP.
This ETS specifies the compliance tests for the connection requirements. This ETS does not include
details concerning the implementation of the tests, nor does it include information on any relevant
regulations.
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 into it by amendment or revision. For undated references the
latest edition of the publication referred to applies.
[1] CCITT Recommendation O.151 (1992): "Error performance measuring
equipment for digital systems at the primary bit rate and above".
[2] CCITT Recommendation O.153 (1992): "Basic parameters for the measurement
of error performance at bit rates below the primary rate".
[3] CCITT Recommendation O.171 (1992): "Timing jitter measuring equipment for
digital systems".
[4] ETS 300 418: "Business TeleCommunications (BTC); 2 048 kbit/s digital
unstructured and structured leased lines (D2048U and D2048S); Network
interface presentation".
NOTE: This ETS also contains a number of informative references which have been included
to indicate the sources from which various material has been derived, hence they do
not have an associated normative reference number. Details of these publications are
given in annex E. In some cases the same publication may have been referenced in
both a normative and an informative manner.
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3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
Background Block Error (BBE): An errored block not occurring as part of a Severely Errored Second
(SES).
BBE ratio: The ratio of errored blocks to total blocks during a fixed measurement interval excluding all
blocks during severely errored seconds and while the leased line connection is in the unavailable state
(see ITU-T Recommendation G.826).
block: A set of 2 048 consecutive bits equivalent to one Sub-MultiFrame (SMF). Each block is monitored
by means of a Cyclic Redundancy Check-4 bit (CRC-4) error check. The length of each block
corresponds to a period of 1 ms.
NOTE: This definition is relevant only to this ETS and is more specific than the generic
definition given in ITU-T Recommendation G.826.
controlled slip: The irretrievable loss or gain of a set of consecutive digit positions in a digital signal, in
which both the magnitude and instant of that loss or gain are controlled, to enable the signal to accord with
a rate different from its own.
errored block: A block in which one or more bits are in error (see ITU-T Recommendation G.826).
Errored Second (ES): A one-second period with one or more errored blocks (see ITU-T
Recommendation G.826).
ES ratio: The ratio of ES to total seconds during a fixed measurement interval. The ES ratio is not
evaluated while the leased line connection is in the unavailable state (see ITU-T Recommendation G.826).
errored Sub-MultiFrame: A Sub-MultiFrame (SMF) where the calculated CRC-4 does not correspond
with the CRC-4 contained within the next SMF (see subclause B.2.2).
frame: A sequence of 256 bits of which the first 8 bits define the frame structure (see annex B).
frame slip: A slip of one complete frame.
leased lines: The telecommunications facilities provided by a public telecommunications network that
provide defined transmission characteristics between NTPs and that do not include switching functions
that the user can control, (e.g. on-demand switching).
multiframe: A sequence of two SMFs containing the multiframe alignment word (see annex B).
Network Termination Point (NTP): All physical connections and their technical access specifications
which form part of the public telecommunications network and are necessary for access to, and efficient
communication through, that public network.
PRBS(2 -1): A Pseudo Random Bit Sequence (PRBS) (as defined in subclause 2.1 of CCITT
Recommendation O.153 [2]).
PRBS(2 -1): A PRBS (as defined in subclause 2.1 of CCITT Recommendation O.151 [1]).
S bits: Bits 4 to 8 (bits S to S ) in frames not containing the frame alignment signal (see annex B).
a4 a8
a
satellite transmission: A transmission via an earth orbiting satellite.
severely disturbed period: For out-of-service measurements, a severely disturbed period occurs when,
over a period of time equivalent to four contiguous blocks, either all the contiguous blocks are affected by
-2
a high bit error density of = 10 , or a loss of signal is observed. For in-service monitoring purposes, a
severely disturbed period is estimated by the occurrence of loss of signal or loss of frame alignment (see
ITU-T Recommendation G.826).
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Severely Errored Second (SES): A one-second period which contains = 805 errored blocks or at least
one severely disturbed period (see ITU-T Recommendation G.826).
SES ratio: The ratio of SES to total seconds during a fixed measurement interval. The SES ratio is not
evaluated while the leased line connection is in the unavailable state (see ITU-T Recommendation G.826).
Sub-MultiFrame (SMF): A sequence of 8 frames, each of 256 bits, over which the CRC-4 is calculated
(see annex B).
uncontrolled slip: The loss or gain of a digit position or a set of consecutive digit positions in a digital
signal, resulting from an aberration of the timing processes associated with transmission or switching of a
digital signal, and in which either the magnitude or the instant of that loss or gain is not controlled.
unavailability period: An unavailability period begins at the onset of 10 consecutive SES. These 10
seconds are considered to be part of the unavailability period. The unavailability period ends at the onset
of 10 consecutive non-SES. These 10 seconds are not considered part of the unavailability period.
unavailable state: The leased line connection is in the unavailable state if an unavailability period is
occurring in one or both directions of transmission.
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
BBE Background Block Error
BIS Bringing Into Service
CRC-4 Cyclic Redundancy Check-4 bit
D2048S 2 048 kbit/s digital structured ONP leased line
EMC ElectroMagnetic Compatibility
ES Errored Second
HDB3 High Density Bipolar code of order 3
NTP Network Termination Point
ONP Open Network Provision
ppm parts per million
PRBS Pseudo Random Bit Sequence
PRC Primary Reference Clock
RAI Remote Alarm Indication
RX RX is a signal input (at either the leased line interface or the test equipment)
SES Severely Errored Second
SMF Sub-MultiFrame
TX TX is a signal output (at either the leased line interface or the test equipment)
UI Unit Interval
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4 Requirements
The performance of the leased line shall comply with these requirements only if the conditions of supply of
the network equipment providing the NTP are met, (e.g. if the equipment is connected to an appropriate
power supply on the customer's premises).
The ITU-T attribute technique is used to express the connection requirements. The following attributes
from ITU-T Recommendation I.140 are specified in this ETS:
- Transfer rate;
- Information transfer susceptance;
- Structure;
- Establishment of connection;
- Symmetry;
- Connection configuration;
- Network performance.
The following network performance sub-attributes are considered relevant for this ETS:
- Transmission delay;
- Jitter;
- Slip;
- Error.
4.1 Attributes
The connection attributes are displayed in table 1. In effect, these attributes define the service being
offered.
The values and the associated compliance tests can be found in the subsequent subclauses.
Table 1: Connection attributes
Connection type attributes Value
Description Nature Reference subclause
Transfer rate
Leased line timing 2 048 kbit/s See 4.1.1.1
Information transfer rate 1 984 kbit/s See 4.1.1.2
Information transfer susceptance No restriction on binary See 4.1.2
content
Structure Frame integrity See 4.1.3
Establishment of connection Without user See 4.1.4
intervention
Symmetry Symmetrical in both See 4.1.5
directions
Connection configuration Point-to-point See 4.1.6
(continued)
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Table 1 (concluded): Connection attributes
Network performance sub-attributes
Connection type attributes Value
Description Nature Reference subclause
Transmission delay Terrestrial and satellite See 4.1.7.1
options
Jitter Input and output ports See 4.1.7.2
Slip (controlled slip) See 4.1.7.3
≤ 5 per 24 hour period
Error parameters (see 5.1.7.4) Terrestrial Satellite
End-to-end performance objectives
Errored Seconds (ES) ratio < 2,000 % < 3,120 %
Severely Errored Seconds (SES) ratio < 0,100 % < 0,156 %
Background Block Errors (BBE) ratio < 0,015 % < 0,023 %
Performance level over 24 hour period
(24 hour test limit)
Errored Seconds (ES) < 1 645 < 2 592
Severely Errored Seconds (SES) < 68 < 112
Background Block Errors (BBE) < 12 732 < 19 933
4.1.1 Transfer rate
4.1.1.1 Leased line timing
Requirement: The leased line shall either:
a) carry user timing within the range 2 048 kbit/s ± 50 parts per million (ppm); or
b) provide timing that is synchronous to the network timing; or
c) take user timing within the range 2 048 kbit/s ± 50 ppm from one input and provide this timing at
both outputs of the leased line.
NOTE 1: In case b), network timing is timing that is derived from the source or sources of timing
that are used for the network. Thus the timing provided by the leased line will be
similar to that provided by other digital services.
NOTE 2: When the timing in both directions is not synchronous, the number of transmitted
E-bits differs from the number of received SMFs. As a consequence, either some valid
E-bits are lost or meaningless E-bits are inserted.
Test: There is no specific test; the leased line provider shall declare which type of timing the leased line
provides and this shall be taken into account during the subsequent tests defined in annex A.
4.1.1.2 Information transfer rate
Requirement: The connection shall be capable of transferring a nominal information rate of 1 984 kbit/s
which is contained within the frame structure defined for the leased line (see subclause 4.1.3).
Test: The test shall be conducted according to subclause A.2.1.
4.1.2 Information transfer susceptance
Requirement: The connection shall be capable of transferring digital information with bit sequence
integrity, and without restriction on binary content, at the nominal rate of 1 984 kbit/s within the defined
frame structure (see subclause 4.1.3).
Test: The test shall be conducted according to subclause A.2.1.
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4.1.3 Structure
The purpose of the structure is to allow the leased line provider to monitor the error performance of the
leased lines from NTP to NTP. The CRC-4 is, therefore, not necessarily transmitted transparently from
NTP to NTP; it may be updated by the leased line provider to determine the location of errors. In order to
allow the terminal equipment to monitor the integrity of the path between the terminal equipment and the
NTP, the NTP is required to provide a correct CRC-4, and to respond correctly with the E-bits in the event
of an incorrectly received CRC-4.
Requirement: For each direction of transmission, the leased line shall accept an input bit stream with a
frame and multiframe structure as defined in annex B. When the leased line input has the above frame
structure and the connection is not in the unavailable state, the output of the leased line shall also conform
to the frame and multiframe structure defined in annex B, with the structure having the same relationship
to the information transferred as at the input, maintaining the frame structure integrity.
Test: The test shall be conducted according to subclauses A.2.1 and A.2.5.1.
4.1.3.1 CRC-4
Requirement: At each NTP, the CRC-4 bits transmitted in the output bit stream shall be as defined in
tables B.1 and B.2 for a complete CRC-4 multiframe and shall correspond to the data transmitted at the
output of the leased line interface, (i.e. the CRC-4 shall be recalculated in the equipment providing the
NTP).
Test: The test shall be conducted according to subclause A.2.5.1.
4.1.3.2 Use of the E-bits
Requirement: At each NTP, the E-bits transmitted in the output bit stream shall indicate errored SMFs in
the input bit stream at that NTP. One E-bit in each multiframe shall be set to binary ZERO for each errored
SMF received in the input bit stream. The E-bits corresponding to non-errored SMFs shall be set to binary
ONE. Any delay between the detection of an errored SMF and the setting of the E-bit that indicates the
errored SMF shall be less than 1 second.
NOTE: The intention is that the CRC-4 verification, and the associated generation of the
E-bits, will be performed in the equipment that provides the NTP in order to indicate
only those errors that have occurred between the terminal equipment and the NTP and
not those errors that have occurred within the network.
Test: The test shall be conducted according to subclause A.2.5.2.
4.1.3.3 Frame synchronization and data transmission capability
Requirement: The leased line shall continue to transparently transmit data in the event of receiving one
or two consecutive incorrect frame alignment signals. On receipt of:
- three consecutive incorrect frame alignment signals; or
- there being = 915 errored SMFs out of 1 000 SMFs,
the leased line shall consider frame alignment to have been lost and initiate a search for frame alignment
during which time the leased line may cease transparent transmission of data.
NOTE: Some implementations may also consider frame alignment to have been lost in the
event that bit 2 in frames not containing the frame alignment signal is in error on three
consecutive occasions. This situation is unlikely to occur except in the event of high
error rates between the terminal equipment and the NTP.
Frame alignment shall not be considered as having been regained until:
a) for the first time, the presence of the correct frame alignment signal; and
b) the absence of the frame alignment signal in the following frame detected by verifying that bit 2 of
the basic frame is a binary ONE; and
c) for the second time, the presence of the correct frame alignment signal in the next frame,
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in which case transparent transmission of the data shall commence within 20 ms provided that the data
does not contain any simulated frame alignment words.
Test: The test shall be conducted according to subclause A.2.5.3.
4.1.3.3.1 Multiframe alignment
Requirement: CRC-4 multiframe alignment shall be achieved if at least two valid CRC-4 multiframe
alignment signals can be located within 8 ms (the time separating two CRC-4 multiframe alignment
signals being 2 ms or a multiple of 2 ms). If multiframe alignment cannot be achieved within 8 ms it shall
be assumed that frame alignment is due to a spurious frame alignment signal and a research for frame
alignment shall be initiated.
NOTE: The research for frame alignment should be started at a point just after the location of
the assumed spurious frame alignment signal. This will usually avoid realignment onto
the spurious frame alignment signal.
Test: The test shall be conducted according to subclause A.2.5.4.
4.1.3.4 Use of the A-bit
There is no requirement of the use of the A-bit within this ETS. The value of the A-bit is undefined at the
output of the leased line.
4.1.3.5 Use of the S bits
a
There is no requirement of the use of the S bits within this ETS. The values of the S bits are undefined at
a a
the output of the leased line.
4.1.4 Establishment of connection
Requirement: Establishment or release of the connection shall not require any protocol exchange or
other intervention at the NTP by the user.
Test: By declaration.
4.1.5 Symmetry
Requirement: The connection shall be symmetrical, i.e. each direction of transmission shall have the
same frame structure and information transfer capability.
Test: The test shall be conducted according to subclause A.2.1.
4.1.6 Connection configuration
Requirement: The connection configuration shall be point-to-point.
Test: By declaration.
4.1.7 Network performance
The network performance sub-attributes are displayed in table 1. The values and the associated
compliance tests can be found in the subsequent subclauses.
4.1.7.1 Transmission delay
Requirement: The requirement depends upon whether satellite transmission is involved in the connection
or not:
- for connections where satellite transmission is not involved, the one way end-to-end delay shall be
less than (10 + 0,01 G) ms, where G is the geographical distance in kilometres, as shown in
figure 1; or
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- for connections where satellite transmission is involved, the one way end-to-end delay shall be less
than 350 ms.
NOTE: These requirements are based on subclauses 2.2 and 2.3 of ITU-T Recommendation
G.114.
Delay (ms)
Geographical distance (km)
Figure 1: Upper limit of delay
There are no requirements for low frequency (below 20 Hz) variation of one way end-to-end delay under
this ETS.
Test: The test shall be conducted according to subclause A.2.2.
4.1.7.2 Jitter
4.1.7.2.1 Jitter tolerance at the network input port
Requirement: The leased line shall function as specified with input jitter being the sum of two band
limited components as defined in table 2.
NOTE: The jitter tolerance for the connection is defined in this way instead of specifying single
jitter frequencies, for the following reasons:
- this method is more representative of the jitter encountered in practice; and
- long regenerator chains may be especially sensitive to single jitter frequencies.
Table 2: Components of input jitter
Filters for generation of jitter Bandpass filter for measurement of Input jitter measured
spectrum (first order) input jitter by bandpass filter
Lower cut-off Upper cut-off (lower cutoff first order) Unit Interval (UI) peak-
(high pass) (low pass) to-peak (maximum)
Only low pass 4 Hz 4 Hz to 100 kHz 1,1 UI
40 Hz 100 kHz 40 Hz to 100 kHz 0,11 UI
NOTE: The purpose of the first order low pass linear filter with an upper cut-off of 4 Hz is to
generate a slope of 20 dB per decade from 4 Hz to 40 Hz on the input jitter spectrum.
The level of jitter (or more correctly wander) generated by this method at frequencies
below 4 Hz is of the order of 1 UI. In principle, there is no requirement for wander and
this wander is an unintended by-product of the method of specifying the jitter. In
practice, wander of this level should not cause any problems for the network.
Test: The test shall be conducted according to subclause A.2.3.
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4.1.7.2.2 Maximum jitter at the network output port
Requirement: The maximum jitter at the output port of the network shall not exceed the limits specified in
table 3, when measured with linear filters with the defined cut-off frequencies.
At frequencies below the lower 3 dB point, the attenuation of the high pass filter shall rise with a value
greater than, or equal to, 20 dB per decade. At frequencies above the upper 3 dB point, the attenuation of
the low pass filtration shall rise with a value greater than, or equal to, 60 dB per decade.
NOTE: This requirement is taken from ITU-T Recommendation G.823.
Table 3: Maximum network output jitter
Measurement filter bandwidth Output jitter
Lower cut-off Upper cut-off UI peak-to-peak
(high pass) (low pass) (maximum)
20 Hz 100 kHz 1,5 UI
18 kHz 100 kHz 0,2 UI
Test: The test shall be conducted according to subclause A.2.3.
4.1.7.3 Controlled slip
Requirement: For at least one of two consecutive periods of 24 hours the number of controlled slips shall
be less than or equal to 5.
NOTE 1: This requirement is based on clause 2 and table 1 of CCITT Recommendation G.822.
NOTE 2: For leased lines operating within the same Primary Reference Clock (PRC) domain,
there should be no slips as long as all secondary clocks are locked to the PRC. Slips
within the specified limit occur only when one or both timing chains from the NTPs to
the PRC are disturbed.
NOTE 3: Figures for uncontrolled slips are not available and are not specified within this ETS.
Test: The test shall be conducted according to subclause A.2.4.
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4.1.7.4 Error
ESs, SESs and BBEs shall be excluded from the measurement of the error performance if the leased line
is in the unavailable state.
NOTE: When microwave links are used in the connection it may not be possible to meet the
requirement in rare periods with very adverse propagation conditions.
4.1.7.4.1 Bringing Into Service (BIS) limits
There are no BIS limits defined under this ETS.
NOTE: BIS limits may be added to this ETS in a later revision. The calculation of BIS limits is
specified in ITU-T Recommendations M.1340 and M.2100.
4.1.7.4.2 Performance level
Requirement: The performance of a leased line either in service or taken out of service in order to
perform an error measurement, shall meet the requirements of table 4.
Table 4: Performance levels over a 24 hour test period for a block length of 2 048 bits
Performance parameter Terrestrial Satellite
ES < 1 645 < 2 592
SES < 68 < 112
BBE < 12 732 < 19 933
Test: The test shall be conducted according to subclause A.2.4.
4.1.7.5 Availability
There is no requirement on availability under this ETS.
NOTE 1: Annex D provides guide-lines on an approach to the specification of availability
requirements for 2 048 kbit/s leased lines.
NOTE 2: At present some leased line providers include availability performance, defined on an
individual basis as a quality of service parameter, as part of the contracted supply
conditions for their leased line offerings.
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ETS 300 419: November 1995
Annex A (normative): Test methods
A.1 General
This annex describes the test principles to determine the compliance of a connection against the
requirements of this ETS.
It is outside the scope of this ETS to identify the specific details of the implementation of the tests.
Details of test equipment accuracy and the specification tolerance of the test devices are not included in
all cases. Where such details are provided they shall be complied with, but the way they are expressed
shall not constrain the method of implementing the test.
NOTE: Attention is drawn to the issue of measurement uncertainty which may be addressed in
future documents. Not all the required test results make allowance for spurious events
during testing (e.g. errors due to ElectroMagnetic Compatibility (EMC) effects), which
may make it necessary to repeat a test.
The test configurations given do not imply a specific realization of the test equipment or test arrangement,
or the use of specific test devices. However, any test configuration used shall provide those test conditions
specified under "connection state", "stimulus" and "monitor" for each individual test.
The test equipment shall be a device, or group of devices that is capable of generating a stimulus signal
conforming to ETS 300 418 [4] and capable of monitoring the signal received from the network interface.
A.1.1 Equipment connection
The leased line may be supplied with either a socket or a hardwired connection. Testing shall be
performed at the defined NTP as this is the point at which compliance with this ETS is required.
A.1.2 Sequence of performing the tests
Error and slip should be tested before jitter and delay; jitter should be tested before information transfer
rate, susceptance, structure and symmetry.
A.2 Test methods
One test may cover more than one requirement. The scope of each test is defined under the heading
"purpose".
A.2.1 Information transfer rate, susceptance and symmetry
Purpose: To verify compliance with the requirements for information transfer rate
(subclause 4.1.1.2), information transfer susceptance (subclause 4.1.2) and
symmetry (subclause 4.1.5).
Test configuration: Test equipment shall be connected to the leased line and the leased line shall
be looped back at the far end by a test equipment capable of reducing jitter to
the levels specified in this ETS (see figure A.1).
RX TX
TX
RX
Test
Test
C onnection
Equipment
Equipment
(Loop - B ack)
RX TX
RX
TX
Figure A.1: Information transfer rate, susceptance and symmetry
Connection State: Available.
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ETS 300 419: November 1995
Stimulus: The test equipment shall generate a High Density Bipolar code of order 3
(HDB3) encoded bit stream complying with a waveform shape as defined in
ETS 300 418 [4], structured according to annex B, containing in bits 9 to 256 of
the frame the bit sequences defined in a, b and c below; this shall be applied to
the input of the leased line. Where the leased line provides network timing, the
test shall be performed with the test equipment synchronous with the timing
provided at the connection output. Where the leased line is capable of carrying
user timing, the tests shall be performed at the bit rate limits of
2 048 kbit/s + 50 ppm and 2 048 kbit/s - 50 ppm.
a) A PRBS(2 -1).
b) A sequence of successive binary ZEROs.
c) A sequence of successive binary ONEs.
Monitor: The bit stream at the output of the leased line.
Results: For each stimulus a), b) and c), for a continuous period of at least one second
no alterations to the binary content shall occur.
For stimulus a), i.e. the PRBS(2 -1), the integrity of the frame structure shall be
maintained, (i.e. where bits 9 to 256 contain a given sequence at the input of the
leased line, the identical sequence shall be contained in bits 9 to 256 at the
output of the leased line).
A.2.2 Delay
Purpose: To verify compliance with the requirements for the one way transmission delay
as specified in subclause 4.1.7.1.
Test configuration: Test equipment shall be connected to the leased line and the leased line shall
be looped back at the far end by a test equipment capable of reducing jitter to
the levels specified in this ETS (see figure A.2).
RX TX
TX RX
Test
Test
Equipment
Connection
Equipment
(Loop - Back)
TX
RX
TX RX
Figure A.2: Delay
Connection State: Available.
Stimulus: The test equipment shall generate a HDB3 encoded bit stream complying with a
waveform shape as defined in ETS 300 418 [4], structured according to
annex B, containing in bits 9 to 256 of the frame a bit stream with a bit sequence
whose repetition period is at least one second; this signal shall be applied to the
input of the leased line. Where the leased line provides network timing, the test
shall be performed with the test equipment synchronous with the timing provided
at the connection output. Where the leased line is capable of carrying user
timing, the tests shall be performed at a bit rate within the limits of
2 048 kbit/s + 50 ppm and 2 048 kbit/s - 50 ppm.
Monitor: The round trip delay between transmission and reception of the bit sequence in
bits 9 to 256.
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ETS 300 419: November 1995
Results: The round trip delay after deduction of the delay introduced by the loop-back test
equipment, shall be less than twice the delay specified in the requirement of
subclause 4.1.7.1.
NOTE: It is not practicable to provide a test of the transmission delay in each individual
direction.
A.2.3 Jitter
Purpose: To verify compliance with the requirements for jitter tolerance at the network
input port as specified in subclause 4.1.7.2.1 and for the maximum jitter allowed
at the network output port as specified in subclause 4.1.7.2.2.
NOTE: Further information on the measurement of jitter can be found in CCITT Supplement
number 3.8, Fascicle IV.4 (1988).
Test configuration: Test equipment shall be connected to both ends of the leased line, (see
figure A.3). Each direction shall be tested separately.
Signal in
Measurement
RX TX
RX
TX
Test
Test
Equipment Connection
Equipment
TX
RX
TX RX
Figure A.3: Jitter
Connection State: Available.
Stimulus: The test equipment shall generate a HDB3 encoded bit stream complying with a
waveform shape as defined in ETS 300 418 [4], structured according to
annex B, and this bit stream shall be applied to the input of the connection.
Where the leased line provides network timing, the test shall be performed with
the test equipment synchronous with the timing provided at the connection
output. Where the leased line is capable of carrying user timing, the tests shall
be performed at the bit rate limits of 2 048 kbit/s + 50 ppm and
2 048 kbit/s - 50 ppm.
Jitter is applied to the input bit stream, where jitter is produced by a voltage
controlled jitter modulator, (see figure A.4), modulated by a signal which
consists of the following two signals added together:
a) a square wave signal produced by a PRBS(2 -1) bit stream generated at
a frequency of 100 Hz. The square wave signal shall be filtered by a first
order linear low pass filter with the cut off freque
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