SIST ETS 300 404 E2:2003

• Abstract:

  Additional definitions of OAM principles for the B-ISDN necessary by r evision of I.610 July 1995.

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• 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 300 404 ed.2 (1997-04) - Broadband Integrated Services Digital Network (B-ISDN); B-ISDN Operation And Maintenance (OAM) principles and functions

SIST ETS 300 404 E2:2003 is the Slovenian standard identical to ETS 300 404 Edition 2 from ETSI, titled Broadband Integrated Services Digital Network (B-ISDN); B-ISDN Operation And Maintenance (OAM) principles and functions. It specifies the minimum OAM functions for the Physical Layer and the Asynchronous Transfer Mode (ATM) layer parts of B-ISDN User-Network Interface (UNI) connections, plus individual Virtual Path (VP) and Virtual Channel (VC) connections. Engineers, network operators and equipment suppliers use it to design, operate and maintain ATM-based B-ISDN networks with continuity check, performance monitoring, loopback and OAM cell handling rules.

What does SIST ETS 300 404 E2:2003 specify?

SIST ETS 300 404 E2:2003 defines the minimum OAM functions needed to run and maintain the Physical Layer and ATM layer aspects of B-ISDN at the UNI, and for individual VP and VC connections routed through the network. The document focuses on OAM at and below the ATM layer and excludes the layers above ATM.

The standard is organised into five clauses and two informative annexes:

• Clauses 1 to 3 cover scope, normative references and abbreviations.
• Clause 4 points to the B-ISDN OAM principles and functions defined in ITU-T Recommendation I.610.
• Clause 5 gives the ETS-specific requirements, clarifications and additions applied when I.610 is used as an European Telecommunication Standard.
• Annex I explains insertion processes for Forward Monitoring (FM) and Backward Reporting (BR) cells.
• Annex II gives a guide to performing Loopbacks.

Annex	What it covers
Annex I	Insertion process for end-to-end or segment FM cells, and BR cell insertion
Annex II	Procedure for performing loopbacks on end-to-end and segment loopback cells

What are the key requirements of SIST ETS 300 404 E2:2003?

SIST ETS 300 404 E2:2003 keeps ITU-T Recommendation I.610 as the base and adds ETS-specific rules for how B-ISDN OAM is applied in practice. The most important points are about where OAM may be observed or inserted, how continuity check is controlled, and how loopback and monitoring behave.

OAM applies only up to the ATM layer

SIST ETS 300 404 E2:2003 applies to the Physical Layer and ATM layer of B-ISDN, and it does not consider layers above ATM. In practice, this means the document is for transport and switching functions, not for higher-layer service behavior.

Intermediate points may monitor and insert, but not terminate, most OAM flows

SIST ETS 300 404 E2:2003 allows intermediate points along a VPC or a VPC segment to monitor OAM cells and insert new OAM cells, but not to terminate the OAM flow, except when segment loopbacks are performed. This matters because network nodes can inspect traffic without becoming the end of the OAM relationship.

VPC and VCC continuity check is a core function

SIST ETS 300 404 E2:2003 requires permanent end-to-end Continuity Check (CC) mechanisms for reserved, permanent and semi-permanent VPCs within the domain of one network operator. Activation and deactivation are handled with Telecommunications Management Network (TMN) procedures when the VPC or VPC segment is set up or released, or later if needed. The document also retains one sending rule: a CC cell is sent downstream when no user cell has been sent for a nominally 1 second.

The same approach is applied to VCCs. Where Performance Management (PM) is performed end-to-end on VCCs or on VCC segments within one operator domain, CC is also expected to be active, although PM-only operation is allowed if the equipment cannot provide CC. In practice, this tells the designer or operator when the network must generate test cells and how they are tied to service activation.

Non-intrusive monitoring is allowed at intermediate Connection Points

SIST ETS 300 404 E2:2003 adds non-intrusive monitoring for end-to-end fault and performance OAM flows at intermediate Connection Points (CPs), including CPs inside a VPC or VCC segment. If implemented, the capability must work simultaneously for a certain number of selected connections per interface, such as UNI or NNI. This is useful when an operator needs extra visibility from the middle of the network without disturbing the OAM flow itself.

Loopback handling is controlled by LLID, CPID and TMN settings

SIST ETS 300 404 E2:2003 clarifies how Segment Loopback (Seg_LB) and end-to-end LB cells are processed. The Loopback Location ID (LLID) field identifies the CP where loopback should occur, and the default all-1s value can represent the connection end-point or, for segment loopback, enabled intermediate CPs. The document also states that the Source ID field is fixed to the default all-1s value, and that returned loopback cells carry the original Correlation Tag.

In practice, this means loopback tests are not just sent and forgotten. The equipment must recognise whether the cell is meant for it, return the right response, and track success using the correlation information.

AIS/RDI and FM cell handling must preserve diagnostic meaning

SIST ETS 300 404 E2:2003 states that if defect type and defect location fields are supported in Alarm Indication Signal/Remote Defect Indication (AIS/RDI) cells, the RDI cell must carry the same values received in the corresponding AIS cell. It also notes that lost FM cells can distort performance calculations. For operators, that means defect reporting and performance results depend on consistent cell handling.

Annex I and Annex II give practical insertion and loopback procedures

SIST ETS 300 404 E2:2003 uses Annex I to explain forced and non-forced insertion for FM and BR cells, including how insertion requests relate to the actual cell stream. Annex II gives the loopback state behavior and the decision logic used when a loopback cell is received, which is helpful for designing ATM equipment that implements these procedures.

What terms does SIST ETS 300 404 E2:2003 define?

SIST ETS 300 404 E2:2003 uses a focused set of OAM terms that matter for ATM operation.

• Asynchronous Transfer Mode (ATM) - the cell-based transport layer on which the B-ISDN OAM functions in this standard are built.
• Broadband Integrated Services Digital Network (B-ISDN) - the network environment covered by the standard, combining broadband transport with integrated services.
• Connection Point (CP) - the point where VP/VC OAM functions are applied; the standard prefers this term because it is clearer than the older wording.
• Forward Monitoring (FM) - OAM cells sent in the forward direction to monitor connection performance.
• Backward Reporting (BR) - OAM cells sent in the reverse direction to report the result of forward monitoring.
• Loopback (LB) - an OAM test method that sends a cell back so the sender can verify path behavior.
• Loopback Location ID (LLID) - the field that identifies which CP should perform the loopback action.
• Virtual Path (VP) and Virtual Channel (VC) - the transport connections inside B-ISDN that the standard applies to at both connection and segment level.

Who uses SIST ETS 300 404 E2:2003?

SIST ETS 300 404 E2:2003 is used by telecom network operators, ATM switch and multiplexer vendors, equipment integrators, and maintenance engineers working on B-ISDN or ATM-based infrastructures. It is also relevant to quality and operations teams that need to specify how continuity check, performance monitoring, loopback and non-intrusive monitoring must behave.

In practice, these users apply the standard when:

• designing ATM equipment OAM features
• setting TMN-controlled activation and release procedures
• testing VPC and VCC continuity
• localising faults and performance impairments
• validating loopback and monitoring behavior at intermediate nodes
• defining responsibilities across operator and customer domains

What changed in SIST ETS 300 404 E2:2003 from the previous edition?

SIST ETS 300 404 E2:2003 is the second edition of ETS 300 404. The foreword says this edition upgrades the document from interim I-ETS status to full ETS status and takes into account the 1995 edition of ITU-T Recommendation I.610. The history section also records a first edition and a second edition.

Which standards are used with SIST ETS 300 404 E2:2003?

SIST ETS 300 404 E2:2003 is based on the following ITU-T Recommendations:

• ITU-T Recommendation I.610 (1995) - the base document for B-ISDN OAM principles and functions; this ETS endorses it with changes, additions and clarifications.
• ITU-T Recommendation I.356 - provides B-ISDN ATM layer cell transfer performance terminology and context used for performance monitoring.
• ITU-T Recommendation G.783 - gives characteristics of SDH equipment functional blocks; the ETS notes where a reference to it in I.610 is not considered.
• ITU-T Recommendation I.361 - defines the B-ISDN ATM layer specification and is referenced where cell fields and PTI handling are discussed.

What does the SIST ETS 300 404 E2:2003 document contain?

SIST ETS 300 404 E2:2003 contains the scope, references, abbreviations and the ETS-specific application of I.610 for B-ISDN OAM. It also points to the structure of I.610 so the reader can place these requirements in the wider OAM framework.

Annex I contains figure-based descriptions of FM and BR cell insertion, including forced and non-forced timing cases. Annex II contains a loopback procedure with a state diagram and step-by-step handling of Seg_LB and end-to-end LB cells, including how a node decides whether to return, forward or discard a loopback cell.

SLOVENSKI STANDARD
01-december-2003
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Broadband Integrated Services Digital Network (B-ISDN); B-ISDN Operation And
Maintenance (OAM) principles and functions
Ta slovenski standard je istoveten z: ETS 300 404 Edition 2
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 404
TELECOMMUNICATION April 1997
STANDARD Second Edition
Source: ETSI TC-NA Reference: RE/NA-052213
ICS: 33.020
Key words: B-ISDN, OAM
Broadband Integrated Services Digital Network (B-ISDN);
B-ISDN Operation And Maintenance (OAM)
principles and functions
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: [e-mail]
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 1997. All rights reserved.

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ETS 300 404: April 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 300 404: April 1997
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Abbreviations.7
4 B-ISDN operation and maintenance principles and functions.8
5 Requirements for the application of ITU-T Recommendation I.610 as an European
Telecommunication Standard .8
Annex I (informative): Insertion process applicable to end-to-end or segment Forward Monitoring
(FM) cells.13
I.1 Processes applicable to Forward Monitoring (FM) cells .13
I.1.1 Forced insertion .13
I.1.2 Non-forced insertion .14
I.2 Process applicable to Backward Reporting (BR) cells .14
I.2.1 Forced insertion .14
I.2.2 Non-forced insertion .15
Annex II (informative): A guide to performing Loopbacks.16
History.19

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ETS 300 404: April 1997
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ETS 300 404: April 1997
Foreword
This second edition European Telecommunication Standard (ETS) has been produced by the Network
Aspects (NA) Technical Committee of the European Telecommunications Standards Institute (ETSI).
This second edition of ETS 300 404, upgrades the standard from interim (I-ETS) status to full ETS status
and takes into account the latest edition of ITU-T Recommendation I.610 (1995).
This ETS describes the Operation And Maintenance (OAM) principles and functions for the Asynchronous
Transfer Mode (ATM) based Broadband Integrated Services Digital Network (B-ISDN).
Transposition dates
Date of adoption: 21 February 1997
Date of latest announcement of this ETS (doa): 31 July 1997
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 31 January 1998
Date of withdrawal of any conflicting National Standard (dow): 31 January 1998

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ETS 300 404: April 1997
Blank page
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ETS 300 404: April 1997
1 Scope
This European Telecommunication Standard (ETS) identifies the minimum set of functions required to
operate and maintain the Physical Layer and the Asynchronous Transfer Mode (ATM) layer aspects of the
Broadband Integrated Services Digital Network (B-ISDN) User-Network Interface (UNI) as well as the
individual Virtual Path (VP) and the Virtual Channel (VC) connections that may be routed through the
B-ISDN.
The functions of the layers above the ATM layer are not considered.
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 I.610 (1995): "B-ISDN operation and maintenance
principles and functions".
[2] ITU-T Recommendation I.356: "B-ISDN ATM layer cell transfer performance".
[3] ITU-T Recommendation G.783: "Characteristics of synchronous digital hierarchy
(SDH) equipment functional blocks".
[4] ITU-T Recommendation I.361: "B-ISDN ATM layer specification".
3 Abbreviations
For the purpose of this ETS, the following abbreviations apply:
ATM Asynchronous Transfer Mode
B-ISDN Broadband Integrated Services Digital Network
BR Backward Reporting
CC Continuity Check
CP Connection Point
NOTE: The use of the expression "Connecting Point" in Recommendation I.610 is ambiguous
in the sense that, depending on the context, it may stand for either an actual
"Connecting Point" as defined in Recommendation I.311 or for a "Connection Point" as
defined in ITU-T Recommendation I.326. This ETS uses only the concept of
"Connection Point", abbreviated as "CP" since it is more appropriate to describe OAM
functions that apply at the VP/VC levels for a specific VP/VC connection.
CPID Connection Point Identifier
FM Forward Monitoring
LB Loopback
LI Loopback indication
LLID Loopback Location Identifier
NNI Network Node Interface
NPC Network Parameter Control
OAM Operation And Maintenance
PDH Plesiochronous Digital Hierarchy
PM Performance Management
PTI Payload Type Identifier
SDH Synchronous Digital Hierarchy
Seg. Segment (of VPC/VCC)
T T Reference Point in B-ISDN
B
UNI User Network Interface
UPC Usage Parameter Control
VC Virtual Channel
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ETS 300 404: April 1997
VCC Virtual Channel Connection
VCI Virtual Channel Identifier
VP Virtual Path
VPC Virtual Path Connection
VPI Virtual Path Identifier
VC AIS Alarm Indication for VC
VC RDI Remote Defect Indication for VC
VP AIS Alarm Indication for VP
VP RDI Remote Defect Indication for VP
4 B-ISDN operation and maintenance principles and functions
The B-ISDN operation and maintenance principles and functions are specified in ITU-T Recommendation
I.610 [1]. ITU-T Recommendation I.610 [1] has the following structure, which is given here for information:
Clause 1: Introduction
Clause 2: OAM principles
Clause 3: OAM levels and flows
Clause 4: Mechanisms to provide OAM flows
Clause 5: OAM functions of the Physical Layer
Clause 6: OAM functions of the ATM Layer
Clause 7: ATM Layer OAM cell format
Annex A: Virtual Channel/Virtual Path Status Monitoring
Annex B: SDLs for activation/deactivation using OAM cells
Annex C: Procedures to be performed when receiving Loopback OAM cells
Appendix A: Examples of OAM Cell Error Detection Codes
5 Requirements for the application of ITU-T Recommendation I.610 as an
European Telecommunication Standard
This ETS endorses ITU-T Recommendation I.610 [1], with the following changes/additions/clarifications.
The following statements give the interpretation of open issues in this Recommendation, to apply in this
ETS.
subclause 1.2 Scope
The functions of the layers above the ATM layer are not considered. Results of the further study of these
layers in ITU-T may not be included in this ETS at a later stage.
subclause 4.2.1 F4 flow mechanism
Intermediate points along the VPC or along the VPC segment may monitor OAM cells passing through
them and insert new OAM cells, but they can not terminate the OAM flow except when segment
loopbacks are performed.
NOTE: In ITU-T Recommendation I.361 [4] a modification of the PTI field is allowed. If this is
done without control of the type of cell, this can lead to a loss of OAM F5 cells.
Table 3/I.610
The reference to ITU-T Recommendation G.783 [3] in note 4 shall not be considered.
Add the following note in the last row (about Cell Delineation function), last column (about Path RDI):
NOTE 6: In future release of I.432 the appropriate information could be transmitted in the
payload dependent byte.
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ETS 300 404: April 1997
Table 5/I.610 and subclause 6.2.1.1.1.1
System protection and failure information for VP/VC failures at the ATM level will be proposed for a later
version of this ETS as soon as they are agreed for inclusion in ITU-T Recommendation I.610 [1].
subclause 6.2.1.1.2 VPC continuity check
Permanent end-to-end CC mechanisms (source and sink processes) shall be provided simultaneously for
all reserved, permanent and semi-permanent VPCs. It is recognized that this requirement may not be
fulfilled by some existing ATM equipments that have been already deployed at the time this ETS was
published. Nevertheless it is intended that ATM equipment OAM capabilities shall evolve to satisfy this
requirement.
This requirement applies to the VPCs which are terminated, at both ends, within the domain controlled by
one network operator (e.g. all VPCs which link VC Switches within the network operator domain or VPCs
which link ATM MUXs under the control of one network operator) and to the VPC Segments
corresponding to such VPCs.
The handling of CC of VPCs terminated in domains controlled by different network operators is subject to
bilateral agreement between those network operators.
Activation/deactivation of the CC mechanisms shall be performed by using the Telecommunications
Management Network (TMN) procedure at the setting-up/release of the VPC or the VPC Segment.
However, depending on the operational requirement of a network operator, the CC mechanism may be
activated/deactivated at any time by using the TMN procedure.
Whether the end-to-end or Segment CC mechanisms can be activated or not for reserved, permanent
and semi-permanent VPCs terminated, at both ends, within the domain controlled by Customers, depends
on the Customer Equipment capability and is under Customer responsibility.
Only option 1) is retained, that is a CC cell is sent downstream by a VPC source-point or a VPC Segment
source-point when no user cell has been sent for a period of nominally 1 second.
subclause 6.2.1.1.3.2 Principles of operation
Replace the second sentence under item 1 by the following text.
There is no need to remove a Seg_LB cell at the intermediate CP along the VPC, that originated the
Seg_LB cell since the Seg_LB will be removed at the Segment end point. This applies also to annex C of
ITU-T Recommendation I.610 [1].
Replace the third sentence under item 2 by the following text.
The possibility to analyse the content of the LLID field of Seg_LB cell shall be provided so as to identify the
CPs where the loopback action has to be performed. It shall be possible to use the default all "1s" value
for the LLID field. In this case Seg_LB cells shall be copied and forwarded in the opposite direction from
any CP within the Segment for which the LLID option is enabled by the TMN.
NOTE: See also annex II/ETS 300 404.
subclause 6.2.1.2 VP performance management functions
Forced insertion of performance monitoring cells is permitted at segment level for the VP and VC level.
NOTE: Concerning the forced and non-forced insertion of Forward monitoring cells see also
annex I/ETS 300 404.
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ETS 300 404: April 1997
subclause 6.2.1.4 Non intrusive monitoring function
This subclause is an addition to the existing ITU-T Recommendation I.610 [1] text.
Non intrusive monitoring of any type of end-to-end Fault and Performance Management OAM flows may
be performed at any intermediate CP along a VPC, this includes intermediate CPs within a VPC Segment
(see note). If implemented, this monitoring capability shall be provided simultaneously for a certain
number of selected VPCs per interface (UNI, NNI). The specification of this number is beyond the scope
of this ETS.
NOTE: The purpose of the non intrusive monitoring function is to provide to network operators,
additional OAM information which cannot be derived from the content of Segment
OAM flows. As an example monitoring both the VP-RDI and the corresponding VP-BR
flow gives the possibility to assess, from any CP, both the status
(available/unavailable) and the end-to-end performance of a VPC. As another
example, monitoring the VP-FM in conjunction with the VP-Segment FM flows
established for all network operator's domains can help to localize performance
impairments in case those impairments are located within the customer network.
subclause 6.2.2.1.2 VCC continuity check
The possibility to activate the end-to-end CC mechanisms shall be provided simultaneously for a certain
number of reserved, permanent and semi-permanent VCCs (see note). This requirement applies to VCCs
which are terminated, at both ends, within the domain controlled by network operators.
Activation/deactivation of the CC mechanisms at the setting-up/release of reserved, permanent or semi-
permanent VCC remains as an option.
NOTE: The end-to-end CC mechanism is intended to be used for VCCs providing a service
which needs an AIS information for "upper layers" in case of defect occurring in the
lower layers.
In the general case, whenever PM is performed end-to-end on VCCs terminated, at both ends, within the
domain controlled by network operators, the end-to-end CC mechanisms (source and sink processes)
shall be activated (see note 1). However it should be possible to activate PM only which might be
interesting if the ATM nodes located at one or both ends are not able to provide the CC mechanisms. The
activation of the end-to-end CC mechanisms shall be performed either before the activation of the PM
process or at the same time by using one of the activation procedures described in subclause 6.2.3 of
ITU-T Recommendation I.610 [1] (see note 2).
In the general case, whenever PM is performed on VCC Segments terminated, at both ends, within the
domain controlled by network operato
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