ETSI ETS 300 419 ed.1 (1995-11)

SLOVENSKI STANDARD
SIST ETS 300 419:1999
01-november-1999

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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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

4.1.3.4 Use of the A-bit....................................................................13

4.1.3.5 Use of the S bits .................................................................13

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

4.1.7.3 Controlled slip......................................................................15

4.1.7.4 Error.....................................................................................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

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

TeleCommunications (BTC) Technical Committee of the European Telecommunications Standards

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

- ETS 300 418: "Business TeleCommunications (BTC); 2 048 kbit/s digital unstructured and

- ETS 300 420: "Business TeleCommunications (BTC); 2 048 kbit/s digital structured leased line

This ETS is based on information from ITU-T Recommendations and ETSI publications and the relevant

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

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

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

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

This ETS is applicable for leased lines, including part time leased lines, for which the establishment or

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

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

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

Background Block Error (BBE): An errored block not occurring as part of a Severely Errored Second

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

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

NOTE: This definition is relevant only to this ETS and is more specific than the generic

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

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

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

frame: A sequence of 256 bits of which the first 8 bits define the frame structure (see annex B).

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

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

PRBS(2 -1): A Pseudo Random Bit Sequence (PRBS) (as defined in subclause 2.1 of CCITT

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).

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

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

Severely Errored Second (SES): A one-second period which contains = 805 errored blocks or at least

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

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

RX RX is a signal input (at either the leased line interface or the test equipment)

TX TX is a signal output (at either the leased line interface or the test equipment)

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

The ITU-T attribute technique is used to express the connection requirements. The following attributes

The following network performance sub-attributes are considered relevant for this ETS:

The connection attributes are displayed in table 1. In effect, these attributes define the service being

The values and the associated compliance tests can be found in the subsequent subclauses.

a) carry user timing within the range 2 048 kbit/s ± 50 parts per million (ppm); or

c) take user timing within the range 2 048 kbit/s ± 50 ppm from one input and provide this timing at

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

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

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.

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).

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

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

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.

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

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

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

Requirement: The leased line shall continue to transparently transmit data in the event of receiving one

the leased line shall consider frame alignment to have been lost and initiate a search for frame alignment

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

b) the absence of the frame alignment signal in the following frame detected by verifying that bit 2 of

c) for the second time, the presence of the correct frame alignment signal in the next frame,