SIST ETS 300 010-1 E1:2003

Transmission and Multiplexing (TM); Synchronous cross connect equipment; 64 kbit/s and n x 64 kbit/s cross connection rate 2 048 kbit/s access ports; Part 1: Core functions and characteristics

Draft ETS on a DXC with a 64 kbit/s core and 2 Mbit/s ports

Prenos in multipleksiranje (TM) – Oprema za sinhrono prespajanje za 64 kbit/s in x 64 kbit/s za dostopovne porte s hitrostjo prespajanja 2 048 kbit/s – 1. del: Jedrne funkcije in karakteristike

General Information

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.040.20 - Transmission systems
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Ref Project: ETSI ETS 300 010-1 ed.1 (1992-11) - Transmission and Multiplexing (TM); Synchronous cross connect equipment; 64 kbit/s and n x 64 kbit/s cross connection rate 2 048 kbit/s access ports; Part 1: Core functions and characteristics

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 010-1 E1:2003
01-december-2003
Prenos in multipleksiranje (TM) – Oprema za sinhrono prespajanje za 64 kbit/s in x
64 kbit/s za dostopovne porte s hitrostjo prespajanja 2 048 kbit/s – 1. del: Jedrne
funkcije in karakteristike
Transmission and Multiplexing (TM); Synchronous cross connect equipment; 64 kbit/s
and n x 64 kbit/s cross connection rate 2 048 kbit/s access ports; Part 1: Core functions
and characteristics
Ta slovenski standard je istoveten z: ETS 300 010-1 Edition 1
ICS:
33.040.20 Prenosni sistem Transmission systems
SIST ETS 300 010-1 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 010-1 E1:2003

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SIST ETS 300 010-1 E1:2003
EUROPEAN ETS 300 010-1
TELECOMMUNICATION November 1992
STANDARD
Source: ETSI TC-TM Reference: T/L 03-17-1
ICS: 33.020, 33.040.40
Transmission, Multiplexing
Key words:
Transmission and Multiplexing (TM);
Synchronous cross connect equipment
64 and n x 64 kbit/s cross connection rate
2 048 kbit/s access ports
Part 1: Core functions and 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 - [e-mail]
X.400: Internet:
Tel.: [phone] - Fax: [phone]
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 1992. All rights reserved.
New presentation - see History box

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ETS 300 010-1: November 1992
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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Contents
Foreword.5
1 Scope .7
2 Normative references .7
3 Definitions. 8
4 Symbols and abbreviations.8
5 Network reference configuration . 9
6 Reference model. 10
7 General characteristics. 10
7.1 Size . 11
7.2 Timing signal. 11
7.2.1 Control of timing signal. 11
7.2.2 Timing performance. 11
8 Functions. 11
8.1 Cross connection . 11
8.2 Management. 11
9 Interfaces. 12
9.1 2 048 kbit/s interface. 12
9.1.1 Physical interface. 12
9.1.2 Frame structure . 12
9.2 Synchronisation interface at 2 048 kHz. 12
9.3 Interface with Telecommunication Management Network (TMN) . 12
9.4 User interface . 12
9.5 Power supply interface. 12
10 Frame alignment and CRC procedure . 12
10.1 Loss of frame alignment . 12
10.2 Recovery of frame alignment. 12
10.3 CRC multiframe alignment in TS 0 . 12
10.4 CRC bit monitoring . 12
11 Defect or failure conditions and performance monitoring. 13
11.1 Defect or failure conditions at the A1 reference point and consequent actions at the B1
and A2 reference points. 13
11.1.1 Defect or failure condition . 13
11.1.1.1 Failure of power supply. 13
11.1.1.2 Loss of incoming signal at 2 048 kbit/s . 13
11.1.1.3 Loss of frame alignment. 13
11.1.1.4 Error ratio 1:10-3. 13
11.1.1.5 Reception of Alarm Indication System (AIS). 13
11.1.1.6 Defect indication from a remote equipment. 13
11.1.2 Consequent actions. 13
11.2 Defect or failure conditions and consequent actions for the core of the equipment . 14
11.2.1 Defect or failure conditions. 14
11.2.1.1 Failure of a connection . 14
11.2.1.2 Loss of synchronisation signal(s). 14

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11.2.2 Consequent actions .14
11.3 Performance monitoring.15
12 Performance .15
12.1 Blocking factor.16
12.2 Jitter .16
12.2.1 Jitter at 2 048 kbit/s output.16
12.2.2 Jitter tolerance at 2 048 kbit/s input .16
12.2.3 Jitter transfer function .16
12.3 Transfer delay.16
12.4 Slips.17
12.5 Error characteristics of the equipment.17
Annex A (normative): Additional requirements for cross connection of channel associated signalling
bits in TS 16 .18
Annex B (normative): Additional TS allocation.23
Annex C (normative): Other timing and slip performance requirements .24
History .25

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ETS 300 010-1: November 1992
Foreword
This European Telecommunication Standard (ETS) has been produced by the Transmission and
Multiplexing (TM) Technical Committee of the European Telecommunications Standards Institute (ETSI) in
order to meet the requirements of network operators and equipment manufacturers for the deployment
and design of synchronous cross connect equipment to be used in synchronous digital leased line
networks.
This is Part one of a two-part standard (ETS 300 010) comprising:
ETS 300 010: Synchronous cross connect equipment - 64 and n x 64 kbit/s cross connection
rate - 2 048 kbit/s access ports.
ETS 300 010 Part 1: Core functions and characteristics.
ETS 300 010 Part 2: Management.
NOTE: Part 2 of this ETS is under development within ETSI TC-TM.
The corresponding ETS for equipment for cross connection of sub-rate signals is under development.

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Blank page

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1 Scope
Part 1 of this ETS describes requirements of cross connect equipment for use in synchronous digital
leased line networks. It covers equipment having 2 048 kbit/s access ports and is limited to the basic
functions, external characteristics and performance of the equipment. Requirements for the management
of the equipment are to be covered in Part 2 of this ETS (ETS 300 010-2) which should be used in
conjunction with this Part of the ETS.
NOTE: Part 2 of this ETS is under development within ETSI TC-TM.
Some network operators may have additional requirements and these are provided in normative Annexes A
to C.
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 amendment or revision. For undated references, the latest edition of the
publication referred to applies.
[1] CCITT Recommendation G.703 (1991): "Physical/electrical characteristics of
hierarchical digital interfaces".
[2] CCITT Recommendation G.704 (1988): "Synchronous frame structures used at
primary and secondary hierarchical levels".
[3] CCITT Recommendation G.706 (1991): "Frame alignment and cyclic redundancy
check (CRC) procedures relating to basic frame structures defined in CCITT
Recommendation G.704".
[4] CCITT Recommendation G.732 (1991): "Characteristics of primary PCM
multiplex equipment operating at 2 048 kbit/s".
[5] CCITT Recommendation G.735 (1988): "Characteristics of primary PCM
multiplex equipment operating at 2 048 kbit/s and offering synchronous digital
access at 384 and/or 64 kbit/s".
[6] CCITT Recommendation G.736 (1988): "Characteristics of a synchronous digital
multiplex equipment operating at 2 048 kbit/s".
[7] CCITT Recommendation G.773 (1988): "Protocol suites for Q interface for
management of transmission systems".
[8] CCITT Recommendation G.811 (1988): "Timing requirements at the outputs of
primary reference clocks suitable for plesiochronous operation of international
digital links".
[9] CCITT Recommendation G.812 (1988): "Timing requirements at the outputs of
slave clocks suitable for plesiochronous operation of international digital links".
[10] CCITT Recommendation G.822 (1988): "Controlled slip rate objectives on an
international digital connection".
[11] CCITT Recommendation G.823 (1988): "The control of jitter and wander within
digital networks which are based on the 2 048 kbit/s hierarchy".
[12] CCITT Recommendation M.20 (1988): "Maintenance philosophy for
telecommunication networks".

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[13] CCITT Recommendation M.3010 (1988): "Principles for a telecommunication
management network".
[14] CCITT Recommendation M.550 (1988): "Performance limits for bringing into
service and maintenance of digital paths, sections and line sections".
[15] CCITT Recommendation O.162: "Specifications for an instrument to monitor the
frame alignment signal of frame structures (frame alignment signal monitor)".
[16] CEPT Recommendation T/TR 02-02, edition 3 (1987): "Rack/telecommunication
centre power supply interfaces".
NOTE: This CEPT Recommendation is to be replaced by prETS 300 132 once available
("Equipment Engineering (EE); Power supply interface at the input to the
telecommunications equipments (DE/EE-2001)").
[17] prETS 300 166: "Transmission and Multiplexing; Physical/electrical
characteristics of hierarchical digital interfaces for equipment using the 2 048
kbit/s-based plesiochronous or synchronous digital hierarchies (DE/TM-3002)".
[18] prETS 300 167: "Transmission and Multiplexing; Functional characteristics of 2
Mbit/s interfaces (DE/TM-3006)".
3 Definitions
For the purpose of this ETS the following definitions apply.
Synchronous cross connect equipment: a device which accepts a number of signals comprising
synchronously multiplexed lower bit rate signals and cross connects the constituent lower bit rate signals.
Blocking factor: the existence of cross connections in a cross connect equipment can block the
establishing of any new cross connection. The blocking factor is the probability that a new cross
connection cannot be made, expressed as a decimal fraction of 1.
Synchronisation signal: a clock control signal obtained from a synchronisation network.
Access port: access ports of a cross connect equipment are input and output ports used to terminate 2
048 kbit/s signals transporting synchronous 64 and n x 64 kbit/s signals to be cross connected.
4 Symbols and abbreviations
For the purpose of this ETS the following symbols and abbreviations apply.
AIS Alarm Indication Signal
CRC Cyclic Redundancy Check
CRC4 Cyclic Redundancy Check procedure relating to the 2 048 kbit/s basic frame
structure according to CCITT Recommendation G.704 [2]
EFS Error Free Signal
FAS Frame Alignment Signal
fr0 Frame 0
ppm part per million
SES Severely Errored Second

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TMN Telecommunication Management Network
TS Time Slot
TS16 Time Slot 16
TS0 NFAS Time Slot 0 without Frame Alignment Signal
UI Unit Interval
5 Network reference configuration
Figure 1 gives typical representation of the cross connect equipment in its network environment.
Synchronous Cross Connect Equipment
Multiplexer Equipment, e.g., according to CCITT Recommendation G.736 [6]
2 048 kbit/s interface
Figure 1: Network reference configuration

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6 Reference model
Figure 2 below provides a reference model for the equipment, including the location and definition of
reference points.
A1 B1
>
X
A2 B2
<
A1 reference point = ETS 300 167 [18] frame logical
signal at receive part of 2 048
kbit/s access port;
A2 reference point = ETS 300 167 [18] frame logical
signal at transmit part of 2 048
kbit/s access port;
B1 reference point = 64 kbit/s data channels derived
from signals at the A1 reference
point before cross connection;
B2 reference point = 64 kbit/s data channels derived
from signals at the B1 reference
point after cross connection;
> = receive part of a 2 048 kbit/s access port
excluding the adaptation of CCITT Recommendation
G.703 [1] signal to ETS 300 167 [18] frame logical
signal;
< = transmit part of a 2 048 kbit/s access port
excluding the adaptation of CCITT Recommendation
G.704 [2] frame logical signal to ETS 300 166 [17]
signal;
X = cross connection function.
NOTE: A1 and A2 (B1 and B2 respectively) relate to the same 2 048 kbit/s access port.
Figure 2: Equipment reference model

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7 General characteristics
7.1 Size
This parameter depends mainly on network growth and can therefore change with time. It shall be possible
to increase the size of an equipment without disturbing the existing traffic.
7.2 Timing signal
7.2.1 Control of timing signal
It should be possible to configure the equipment to derive the internal timing signal from:
a) one of a number of external source(s) at 2 048 kHz according to subclause 9.2;
b) one of a number of 2 048 kbit/s signal(s) according to subclause 9.1;
c) an internal oscillator.
On fault condition on the active synchronisation signal it shall be possible to program a fall-back strategy
up to three steps; see subclause 11.2.1.2.
Complementary information corresponding to management aspects of the equipment will be provided in
ETS 300 010-2 (currently under development).
11
-
The frequency accuracy of signals in a) and b) should normally be ± 1:10 . To take into account possible
frequency deviations on these signals occurring due to failure in the synchronous network, the design of
timing derivation circuits should assume a frequency accuracy of ± 1 ppm.
The requirements for the 2 048 kbit/s physical interface according to subclause 9.1.1 are not affected.
7.2.2 Timing performance
The timing performance of the internal clock shall comply with CCITT Recommendation G.812 [9]. In the
holdover mode, the local clock requirements of § 2.2.2 of CCITT Recommendation G.812 [9] shall be met.
NOTE: For other timing performance options, refer to Annex C.
8 Functions
The cross connect equipment shall perform the functions given in subclauses 8.1 and 8.2 of this ETS.
8.1 Cross connection
Cross connection of 64 and n x 64 kbit/s signals, bidirectional.
The n x 64 kbit/s signals shall be according to § 5.2 of CCITT Recommendation G.704 [2]. 6 x 64 kbit/s
(384 kbit/s) signals according to § 2.2.3 of CCITT Recommendation G.735 [5] should be taken into
account in the design of the equipment. The equipment shall maintain octet sequence integrity of the
signals being cross connected.
NOTE 1: For some n x 64 kbit/s applications it may be necessary to maintain octet sequence
integrity within each frame.
NOTE 2: Refer to Annex B for other n x 64 kbit/s Time Slot (TS) allocations.
8.2 Management
This includes control functions and provision of maintenance information and will be detailed in Part 2 of this
ETS.

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9 Interfaces
9.1 2 048 kbit/s interface
9.1.1 Physical interface
The 2 048 kbit/s physical interface shall be according to section 6 of CCITT Recommendation G.703 [1].
9.1.2 Frame structure
The details of frame structure carrying channels at various bit rates in 2 048 kbit/s shall be according to §
2.3 and § 5 of CCITT Recommendation G.704 [2]. Bit 1 of the frame shall be used in accordance with §
2.3.3 of CCITT Recommendation G.704 [2], i.e. for a Cyclic Redundancy Check (CRC) check bit
procedure. However, § 2.2.3 of CCITT Recommendation G.735 [5] for TS allocation of 384 kbit/s sound
programme signals contained in a 2 048 kbit/s frame should be taken into account.
NOTE: Refer to Annex B for other n x 64 kbit/s TS allocation.
9.2 Synchronisation interface at 2 048 kHz
The physical and electrical characteristics of the synchronisation interface shall be according to section 10
of CCITT Recommendation G.703 [1].
9.3 Interface with Telecommunication Management Network (TMN)
The interface with the TMN shall be the Q interface according to CCITT Recommendation G.773 [7].
9.4 User interface
The user interface shall be the F interface according to CCITT Recommendation M.3010 [13].
9.5 Power supply interface
The power supply interface shall be the A interface according to CEPT Recommendation T/TR 02-02 [16]
(See NOTE to clause 2).
10 Frame alignment and CRC procedure
An illustration of the procedure is given in figure 2 of CCITT Recommendation G.706 [3].
10.1 Loss of frame alignment
The strategy for loss of frame alignment shall be according to § 4.1.1 of CCITT
Recommendation G.706 [3].
10.2 Recovery of frame alignment
The strategy for recovery of frame alignment shall be according to § 4.1.2 of CCITT Recommendation
G.706 [3].
10.3 CRC multiframe alignment in TS 0
CRC multiframe alignment in TS 0 shall comply with § 4.2 of CCITT Recommendation G.706 [3].
10.4 CRC bit monitoring
The CRC bit monitoring shall be performed according to § 4.3 of CCITT Recommendation G.706 [3].

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11 Defect or failure conditions and performance monitoring
11.1 Defect or failure conditions at the A1 reference point and consequent actions at the B1
and A2 reference points
11.1.1 Defect or failure condition
The equipment shall detect the conditions given in the 11.1.1.1 to 11.1.1.6 subclauses.
11.1.1.1 Failure of power supply
11.1.1.2 Loss of incoming signal at 2 048 kbit/s
The detection of this defect is required only when it does not result in an indication of loss of frame
alignment.
11.1.1.3 Loss of frame alignment
See subclause 10.1.
11.1.1.4 Error ratio 1:10-3
The detection of this defect shall comply with § 4.1.5 of CCITT Recommendation G.736 [6].
The detection of this defect is optional. When required, it can be determined by counting either the number
of errored frame alignment signals or the number of errored bits in frame alignment signals or by using the
CRC4 procedure. Part 2 of this ETS will cover the details of this.
11.1.1.5 Reception of Alarm Indication System (AIS)
The detection of AIS shall comply with § 4.2.4 of CCITT Recommendation G.736 [6], and § 3.3.2 of
CCITT Recommendation O.162 [15].
11.1.1.6 Defect indication from a remote equipment
11.1.2 Consequent actions
Further to the detection of a defect or a failure condition, appropriate consequent actions shall be taken as
specified in table 1. The consequent actions should be taken as soon as possible:
- AIS at B1 reference point should be applied within 3 ms of the detection of the relevant defect or
failure condition;
- the maximum period between the detection of a defect or a failure condition and the transmission of
defect indication at the A2 reference point shall be of the order of 100 ms;
- the maximum period between the detection of a defect or a failure condition and the generation of
any failure information is dependent on the maintenance strategy for the equipment. This will be
covered in Part 2 of this ETS which will specify the management aspects of cross connect
equipment.
-3
However, in case of the fault condition error ratio 1:10 provision shall be made for some form of
persistence check (e.g. 2 or 3 x the integration time) with appropriate confidence that a fault condition
does exist (cf §§ 4.1.5.1 and 4.1.5.2 of CCITT Recommendation G.736 [6]).

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Table 1: Defect or failure conditions and consequent actions for a 2 048 kbit/s access port
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¿
‡         ‡      Consequent actions         ‡
‡Defect or failureˆ˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡condition at the ‡ Failure ‡   Defect    ‡ AIS applied to ‡
‡A1 reference   ‡information‡ indication to  ‡ data TS at B1 ‡
‡point      ‡ generated ‡ remote end at A2 ‡  reference  ‡
‡         ‡ (NOTE 1) ‡ reference point ‡   point   ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡Failure of power ‡      ‡        Yes        ‡
‡supply      ‡      ‡     if practicable     ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜´˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡Loss of incoming ‡      ‡  Yes, bit 3   ‡   Yes    ‡
‡signal      ‡      ‡  TS0 NFAS   ‡        ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡Loss of frame  ‡      ‡  Yes, bit 3   ‡   Yes    ‡
‡alignment    ‡      ‡  TS0 NFAS   ‡        ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡Error ratio   ‡      ‡  Yes, bit 3   ‡   Yes    ‡
-3
‡1:10 (NOTE 4) ‡      ‡  TS0 NFAS   ‡  (NOTE 2)  ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡Defect indication‡      ‡         ‡        ‡
‡received from  ‡      ‡    No     ‡    No    ‡
‡remote end,   ‡      ‡         ‡        ‡
‡bit 3 TS0 NFAS  ‡      ‡         ‡        ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜¯˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡AIS received   ‡      ‡  Yes (NOTE 3) ‡   Yes    ‡
‡         ‡      ‡    (NOTE 5) ‡        ‡
ˆ˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜`˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜·
‡NOTE 1: Consequent actions related to the generation of failure ‡
‡    information will be specified in ETS 300 010-2 (currently‡
‡    under development). These actions could be taken at the ‡
‡    level of the equipment (e.g. bell, lamp,.) or at the  ‡
‡    level of the management of the equipment.        ‡
‡                                 ‡
‡NOTE 2: Provision shall be made for disabling this action.    ‡
‡                                 ‡
‡NOTE 3: In order to enable appropriate actions at the remote end,‡
‡    the indication of reception of AIS may be transmitted in ‡
‡    addition to any other defect information to the remote  ‡
‡    end. The use of the 4 kbit/s data link on Sa4 in TSO NFAS‡
‡    or the use of a free Sa bit of TSO NFAS is suggested for ‡
‡    this application.                    ‡
‡                                 ‡
‡NOTE 4: The detection of this defect condition is optional.   ‡
‡                                 ‡
‡NOTE 5: This consequent action is optional.           ‡
�˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜˜�
11.2 Defect or failure conditions and consequent actions for the core of the equipment
11.2.1 Defect or failure conditions
The equipment shall detect the conditions given in subclauses 11.2.1.1 and 11.2.1.2.
11.2.1.1 Failure of a connection
A connection inside the equipment shall be deemed to have failed when the 64 or n x 64 kbit/s path
between the A1 and A2 reference points of the relevant ports is not available for a period of more than 1
second.
11.2.1.2 Loss of synchronisation signal(s)
The equipment is timed by its own internal oscillator in the case where this is not the normal mode of
operation. In the case of loss of active synchronisation reference, the equipment shall switch over to
another reference according to the programmed fall-back strategy. In the case of selecting the internal
oscillator (case c) of subclause 7.2.1) the equipment shall enter into the holdover mode.
11.2.2 Consequent actions
Further to the detection of a defect or a failure condition, appropriate consequent actions shall be taken as
specified in table 2. The consequent actions shall be taken as soon as possible:
- the application of AIS at relevant B2 reference points (or B1 or A2) should be taken within 3 ms of
the detection of the failure condition;

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SIST ETS 300 010-1 E1:2003
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ETS 300 010-1: November 1992
- the maximum period between the detection of a defect or failure condition and the transmission of a
defect indication at the A2 reference point should be of the order of 100 ms;

- the maximum period between the detection of a defect or failure condition and the generation of any
failure information is dependent on the maintenance strategy for the equipment. ETS 300 010-2
(currently under development) will specify the management aspects of cross connect equipment.
Table 2: Defect or failure conditions and consequent
...