SIST EN 301 163-2-1 V1.1.2:2003

• Abstract:

  Provide specifications for ATM equipment to be used in the ETSI region. Such specifications will ensure compatibility between equipment by identifying which functions are mandatory for interworking and which can be considered as truly optional.

• 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 EN 301 163-2-1 V1.1.2 (1999-05) - Transmission and Multiplexing (TM); Generic requirements of Asynchronous Transfer Mode (ATM) transport functionality within equipment; Part 2-1: Functional model for the transfer and layer management plane

SIST EN 301 163-2-1 V1.1.2:2003 is the Slovenian adoption of ETSI EN 301 163-2-1 Version 1.1.2. It defines the functional model for Asynchronous Transfer Mode (ATM) transport functionality within equipment, with a focus on the transfer and layer management plane. The standard is written for ATM equipment used in the ETSI region, and it separates functions that are mandatory for interworking from functions that are optional.

What does SIST EN 301 163-2-1 V1.1.2:2003 specify?

SIST EN 301 163-2-1 V1.1.2:2003 specifies the functional architecture used to carry ATM traffic through transport equipment and to manage that transport at layer level. It does this by defining atomic functions, their inputs and outputs, and the way they are grouped into layer networks and adaptation functions.

Clause	What it covers
1	Scope and purpose
2	Normative references
3	Definitions, abbreviations and symbols
4	Transmission path to ATM virtual path adaptation functions
5	ATM virtual path layer network functions
6	ATM virtual path to ATM virtual channel adaptation functions
7	ATM virtual channel layer network functions
8	ATM virtual channel to ATM client adaptation functions

The document is part of a multi-part EN for generic ATM transport functionality. In the foreword and introduction, SIST EN 301 163-2-1 V1.1.2:2003 is placed alongside Part 1, which covers functional characteristics and equipment performance. This part focuses on the formal model for the transfer and layer management plane.

The introduction also explains that the document follows the ITU-T G.805 view of transport networks. That matters because it tells the reader that the model is layered and technology-neutral in structure, even though the functions are described for ATM, SDH and PDH use cases.

What are the key requirements of SIST EN 301 163-2-1 V1.1.2:2003?

SIST EN 301 163-2-1 V1.1.2:2003 defines a layered set of source, sink, connection, monitoring, traffic management and loopback functions. In practice, that means an implementation is expected to move ATM cells between transport paths and ATM layers in a controlled, observable way, with clear defect reporting and management interfaces.

Transmission path to ATM virtual path adaptation

Clause 4 defines adaptation from transmission paths to the ATM virtual path layer, including source and sink functions for SDH and PDH paths such as S3, S4, P12s and P31s. The source functions insert ATM cells into the relevant transport structure, while the sink functions recover the cells and check that the mapping is still valid.

These functions share common processing steps such as congestion control based on CLP, GFC processing, TP usage measurement, HEC processing, scrambling or descrambling, and cell stream mapping. That is important in practice because an implementer has to support both the transport mapping and the ATM cell integrity checks, not just the payload transfer.

The sink functions also verify the payload-specific bytes used to prove that both ends are provisioned for the same mapping. Where the mapping does not use a particular payload byte, the receiver ignores it.

ATM virtual path layer network functions

Clause 5 defines the ATM virtual path layer network, including connection, trail termination, monitoring, segment, traffic management and loopback functions. The Avp_C connection function routes Characteristic Information (CI) between connection points by matrix connection, so the equipment can be configured as a network element rather than a fixed point-to-point device.

The Avp_TT_So and Avp_TT_Sk functions handle end-to-end VP Operation, Administration and Maintenance (OAM) tasks such as Continuity Check, Performance Monitoring, Remote Defect Indication (RDI) and Alarm Indication Signal (AIS). In practice, this is what lets the equipment detect a working path, report a remote fault, and generate OAM cells for management systems.

The monitoring and loopback functions extend this to non-intrusive checking and test loops. That matters because operators can verify a live path or segment without redesigning the service routing.

ATM virtual channel layer network functions

Clause 7 repeats the same model at the Virtual Channel (VC) level. The Avc_C connection function performs matrix routing for VC-layer CI, while Avc_TT_So and Avc_TT_Sk handle F5 OAM for continuity check, PM, VC-AIS and VC-RDI.

The AvcT traffic management functions add congestion handling at VC level. The source can set Explicit Forward Congestion Indicator (EFCI) in the cell header, and the sink can perform Usage Parameter Control (UPC), Network Parameter Control (NPC), traffic shaping and usage measurement where implemented. For a buyer or engineer, that tells you the standard covers not only transport but also how the equipment should behave under congestion.

ATM virtual channel to ATM client adaptation

Clause 8 defines ATM Virtual Channel to ATM Client Adaptation functions in source and sink directions. These are described as AAL processes for a given VCC and are marked for further study, with candidate payloads such as Frame Relay, HDLC, Internet Protocol, CBDS, N-ISDN interworking and LAN traffic. This section matters if the equipment must sit between ATM transport and a client service rather than only between transport layers.

What terms does SIST EN 301 163-2-1 V1.1.2:2003 define?

• ATM (Asynchronous Transfer Mode) - The cell-based transfer technology used throughout the document for transport and adaptation functions.
• VP (Virtual Path) - A layer that groups ATM cells for transport and management as a path.
• VC (Virtual Channel) - A finer-grained ATM layer inside a VP, used for individual connections.
• CI (Characteristic Information) - The information that is routed between connection points in a layer network.
• OAM (Operation, Administration and Maintenance) - The control and management cells and procedures used for continuity check, defects, performance monitoring and loopback.
• HEC (Header Error Check) - The header field processing used to verify and, where applicable, correct ATM cell headers.
• AIS (Alarm Indication Signal) - A management alarm state carried by OAM cells to indicate a fault condition.
• RDI (Remote Defect Indication) - A defect indication sent to report a fault detected at the remote end.

Who uses SIST EN 301 163-2-1 V1.1.2:2003?

SIST EN 301 163-2-1 V1.1.2:2003 is used by manufacturers of ATM transport equipment, network operators, and system integrators who need interoperable behavior between vendors. It is also relevant to quality managers, test labs and procurement teams that need to check which functions are mandatory, which are optional, and how OAM and congestion handling are expected to work.

Engineers use it to design or verify SDH and PDH mappings, VP/VC routing, and ATM OAM handling. Operations teams use it to understand what alarms, loopbacks and performance indicators the equipment should expose to the management layer.

Which standards are used with SIST EN 301 163-2-1 V1.1.2:2003?

• EN 300 417-1-1 - Supplies the definitions and symbols used in the document, and the generic processes and performance model it relies on.
• ETS 300 147 - Defines SDH multiplexing structure and the ATM mapping references used for VC-3 and VC-4 related adaptation.
• ETS 300 298-1 and ETS 300 298-2 - Provide ATM functional characteristics and ATM layer specification, including GFC and cell-format rules.
• ETS 300 300 - Supplies the physical layer rules used for HEC processing and scrambling or descrambling behavior.
• ETS 300 337 - Defines generic frame structures used for ATM mapping in PDH-related paths such as P12s and P31s.
• ETS 300 354 - Gives the B-ISDN Protocol Reference Model, which is used to justify how unassigned and idle cells are treated.
• ETS 300 404 - Provides the OAM principles and functions used for continuity check, PM, AIS, RDI and loopback.
• EN 300 301 - Provides traffic control and congestion control behavior, including EFCI, UPC/NPC and shaping.
• EN 300 417-1-1, EN 300 417-4-1 and EN 300 417-5-1 - Support the transport-functional view, and the bibliography points to the SDH and PDH path-layer companion parts.
• ITU-T G.707, G.803, G.804, G.805, G.832, I.150, I.321, I.326, I.361, I.371, I.432, I.432.1, I.432.2, I.610 and I.732 - Supply the underlying transport, ATM, OAM and layer-network concepts that the ETSI model follows.

What does the SIST EN 301 163-2-1 V1.1.2:2003 document contain?

SIST EN 301 163-2-1 V1.1.2:2003 contains atomic-function diagrams, signal tables and explanatory text for each source, sink, connection and monitoring function. It shows how ATM cells are mapped into SDH and PDH payload structures, how headers are checked, and how defect and alarm indications are generated or reported.

The document also includes tables for input and output signals, and figures showing how each atomic function is decomposed into specific and common processes. For loopback handling, it includes a condition table that shows how received loopback cells are treated. For the client-adaptation section, it lists candidate payload types that may be supported by the AAL process.

SLOVENSKI STANDARD
01-december-2003
3UHQRVLQPXOWLSOHNVLUDQMH70±*HQHULþQH]DKWHYHSUHQRVQHIXQNFLRQDOQRVWL
DVLQKURQHJDSUHQRVQHJDQDþLQD$70YVDPLRSUHPL±GHO)XQNFLMVNLPRGHO
UDYQLQH]DXSUDYOMDQMHSUHQRVDLQSODVWL
Transmission and Multiplexing (TM); Generic requirements of Asynchronous Transfer
Mode (ATM) transport functionality within equipment; Part 2-1: Functional model for the
transfer and layer management plane
Ta slovenski standard je istoveten z: EN 301 163-2-1 Version 1.1.2
ICS:
33.040.20 Prenosni sistem Transmission systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN 301 163-2-1 V1.1.2 (1999-05)
European Standard (Telecommunications series)
Transmission and Multiplexing (TM);
Generic requirements of Asynchronous Transfer Mode (ATM)
transport functionality within equipment;
Part 2-1: Functional model for the transfer
and layer management plane
2 EN 301 163-2-1 V1.1.2 (1999-05)
Reference
DEN/TM-01016-2-1 (aroi9idc.PDF)
Keywords
ATM, transport, B-ISDN, SDH, transmission
ETSI
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Copyright Notification
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The copyright and the foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1999.
All rights reserved.
ETSI
3 EN 301 163-2-1 V1.1.2 (1999-05)
Contents
Intellectual Property Rights.5
Foreword .5
1 Scope.6
2 References.6
3 Definitions, abbreviations and symbols.7
3.1 Definitions.7
3.2 Abbreviations .7
3.2.1 Modelling specific abbreviations.7
3.2.2 General abbreviations .8
3.3 Symbols and diagrammatic conventions.9
3.4 Introduction .9
4 Transmission path to ATM virtual path adaptation functions .11
4.1 S3 path adaptation functions .11
4.1.1 S3 path to ATM virtual path adaptation source function S3/Avp_A_So.11
4.1.2 S3 path to ATM virtual path adaptation sink function S3/Avp_A_Sk.15
4.2 S4 path adaptation functions .18
4.2.1 S4 path to ATM virtual path adaptation source function S4/Avp_A_So.18
4.2.2 S4 path to ATM virtual path adaptation sink function S4/Avp_A_Sk.23
4.3 S4-4v path adaptation functions .26
4.3.1 S4-4v path to ATM virtual path adaptation source function S4-4v/Avp_A_So.26
4.3.2 S4-4v path to ATM virtual path adaptation sink function S4-4v/Avp_A_Sk .26
4.4 S4-4c path layer adaptation functions.27
4.4.1 S4-4c path to ATM virtual path adaptation source function S4-4c/Avp_A_So.27
4.4.2 S4-4c path to ATM virtual path adaptation sink function S4-4c/Avp_A_Sk.27
4.5 Cell based adaptation functions.27
4.6 P12s path adaptation functions.27
4.6.1 P12s path to ATM virtual path adaptation source function P12s/Avp_A_So.27
4.6.2 P12s path to ATM virtual path adaptation sink function P12s/Avp_A_Sk.30
4.7 P31s path adaptation functions.34
4.7.1 P31s path to ATM virtual path adaptation source function P31s/Avp_A_So.34
4.7.2 P31s path to ATM virtual path adaptation sink function P31s/Avp_A_Sk.38
5 ATM virtual path layer network functions .41
5.1 ATM virtual path connection function Avp_C.42
5.2 ATM virtual path trail termination functions.43
5.2.1 ATM virtual path trail termination source function Avp_TT_So .43
5.2.2 ATM virtual path trail termination sink function Avp_TT_Sk .44
5.3 ATM virtual path monitoring functions.47
5.3.1 ATM virtual path non-intrusive monitoring function Avpm_TT_Sk.47
5.4 ATM virtual path segment functions .50
5.4.1 ATM virtual path segment trail termination source function AvpS_TT_So.50
5.4.2 ATM virtual path segment trail termination sink function AvpS_TT_Sk.51
5.4.3 ATM virtual path segment to ATM virtual path adaptation source function AvpS/Avp_A_So .53
5.4.4 ATM virtual path segment to ATM virtual path adaptation sink function AvpS/Avp_A_Sk .54
5.5 ATM virtual path traffic management functions .54
5.5.1 ATM virtual path traffic management trail termination source function AvpT_TT_So .55
5.5.2 ATM virtual path traffic management trail termination sink function AvpT_TT_Sk.56
5.5.3 ATM virtual path traffic management to ATM virtual path adaptation source function
AvpT/Avp_A_So.57
5.5.4 ATM virtual path traffic management to ATM virtual path adaptation sink function
AvpT/Avp_A_Sk.58
5.6 ATM virtual path loopback functions.59
5.6.1 ATM virtual path loopback source function Avplb_TT_So .59
5.6.2 ATM virtual path loopback sink function Avplb_TT_Sk.60
ETSI
4 EN 301 163-2-1 V1.1.2 (1999-05)
6 ATM virtual path to ATM virtual channel adaptation functions.62
6.1 ATM virtual path to ATM virtual channel adaptation source function Avp/Avc_A_So.62
6.2 ATM virtual path to ATM virtual channel adaptation sink function Avp/Avc_A_Sk.63
7 ATM virtual channel layer network functions.66
7.1 ATM virtual channel connection function Avc_C.67
7.2 ATM virtual channel trail termination functions .68
7.2.1 ATM virtual channel trail termination source function Avc_TT_So .68
7.2.2 ATM virtual channel trail termination sink function Avc_TT_Sk.70
7.3 ATM virtual channel monitoring functions .72
7.3.1 ATM virtual channel non-intrusive monitoring function Avcm_TT_Sk.72
7.4 ATM virtual channel segment functions.75
7.4.1 ATM virtual channel segment trail termination source function AvcS_TT_So.75
7.4.2 ATM virtual channel segment trail termination sink function AvcS_TT_Sk.76
7.4.3 ATM virtual channel segment to ATM virtual channel adaptation source function AvcS/Avc_A_So.78
7.4.4 ATM virtual channel segment to ATM virtual channel adaptation sink function AvcS/Avc_A_Sk.79
7.5 ATM virtual channel traffic management functions .80
7.5.1 ATM virtual channel traffic management trail termination source function AvcT_TT_So.80
7.5.2 ATM virtual channel traffic management trail termination sink function AvcT_TT_Sk.81
7.5.3 ATM virtual channel traffic management to ATM virtual channel adaptation source function
AvcT/Avc_A_So .82
7.5.4 ATM virtual channel traffic management to ATM virtual channel adaptation sink function
AvcT/Avc_A_Sk .83
7.6 ATM virtual channel loopback functions .84
7.6.1 ATM virtual channel loopback source function Avclb_TT_So.84
7.6.2 ATM virtual channel loopback sink function Avclb_TT_Sk.85
8 ATM virtual channel to ATM client adaptation functions .87
8.1 ATM virtual channel to ATM client adaptation source function Avc/XXX_A_So .87
8.2 ATM virtual channel to ATM Client Adaptation Sink function Avc/XXX_A_Sk.88
Bibliography.90
History.91
ETSI
5 EN 301 163-2-1 V1.1.2 (1999-05)
Intellectual Property Rights
IPRs essential or potentially essential to the present document may have been declared to ETSI. The information
pertaining to these essential IPRs, if any, is publicly available for ETSI members and non-members, and can be found
in SR 000 314: "Intellectual Property Rights (IPRs); Essential, or potentially Essential, IPRs notified to ETSI in respect
of ETSI standards", which is available free of charge from the ETSI Secretariat. Latest updates are available on the
ETSI Web server (http://www.etsi.org/ipr).
Pursuant to the ETSI IPR Policy, no investigation, including IPR searches, has been carried out by ETSI. No guarantee
can be given as to the existence of other IPRs not referenced in SR 000 314 (or the updates on the ETSI Web server)
which are, or may be, or may become, essential to the present document.
Foreword
This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Transmission
and Multiplexing (TM), in order to provide inter-vendor and inter-operator compatibility of Asynchronous Transfer
Mode (ATM) equipment.
The present document is part 2 of a multi-part EN covering the generic requirements of Asynchronous Transfer Mode
(ATM) transport functionality within equipment, as identified below:
Part 1: "Functional characteristics and equipment performance";
Part 2: "Functional model for the transfer and layer management plane".
National transposition dates
Date of adoption of this EN: 23 April 1999
Date of latest announcement of this EN (doa): 31 July 1999
Date of latest publication of new National Standard
or endorsement of this EN (dop/e): 31 January 2000
Date of withdrawal of any conflicting National Standard (dow): 31 January 2000
ETSI
6 EN 301 163-2-1 V1.1.2 (1999-05)
1 Scope
The purpose of the present document is to provide specifications for Asynchronous Transfer Mode (ATM) equipment to
be used in the ETSI region. Such specifications will ensure compatibility between equipment by identifying which
functions are mandatory for interworking and which can be considered as truly optional. Of course it is not the intention
to prevent manufacturers or procurers from following an alternative specification, but the consequences should become
clear from the present document.
The document will be in two parts, producing a list of functions and processes in the first part and a formal
representation of transfer transport and layer management functions in the second part. The specification will take
advantage of the work done in ITU but will take the work further with an ETSI European view. This means: the
identification of ITU options to be mandatory in Europe, deletion of options not required for Europe, creation of new or
revised descriptions where necessary, identification of guideline or benchmark performance parameters for classes of
equipment.
2 References
The following documents contain provisions which, through reference in this text, constitute provisions of the present
document.
• References are either specific (identified by date of publication, edition number, version number, etc.) or
non-specific.
• For a specific reference, subsequent revisions do not apply.
• For a non-specific reference, the latest version applies.
• A non-specific reference to an ETS shall also be taken to refer to later versions published as an EN with the same
number.
[1] ETS 300 147: "Transmission and Multiplexing (TM); Synchronous Digital Hierarchy (SDH);
Multiplexing structure".
[2] ETS 300 298-1: "Broadband Integrated Services Digital Network (B-ISDN); Asynchronous
Transfer Mode (ATM); Part 1: B-ISDN ATM functional characteristics
[ITU-T Recommendation I.150 (1995)]".
[3] ETS 300 298-2: "Broadband Integrated Services Digital Network (B-ISDN); Asynchronous
Transfer Mode (ATM); Part 2: B-ISDN ATM layer specification".
[4] ETS 300 300 (1997): "Broadband Integrated Services Digital Network (B-ISDN); Synchronous
Digital Hierarchy (SDH) based user network access; Physical layer User Network Interfaces (UNI)
for 155 520 kbit/s and 622 080 kbit/s Asynchronous Transfer Mode (ATM) B-ISDN applications".
[5] EN 300 301 (V1.2): "Broadband Integrated Services Digital Network (B-ISDN); Traffic control
and congestion control in B-ISDN".
[6] ETS 300 337: "Transmission and Multiplexing (TM); Generic frame structures for the transport of
various signals (including Asynchronous Transfer Mode (ATM) cells and Synchronous Digital
Hierarchy (SDH) elements) at the ITU-T Recommendation G.702 hierarchical rates of
2 048 kbit/s, 34 368 kbit/s and 139 264 kbit/s".
[7] ETS 300 354: "Broadband Integrated Services Digital Network (B-ISDN); B-ISDN Protocol
Reference Model (PRM)".
[8] ETS 300 404: "Broadband Integrated Services Digital Network (B-ISDN); B-ISDN Operation And
Maintenance (OAM) principles and functions".
[9] EN 300 417-1-1 (V1.1): "Transmission and Multiplexing (TM); Generic requirements of transport
functionality of equipment; Part 1-1: Generic processes and performance".
ETSI
7 EN 301 163-2-1 V1.1.2 (1999-05)
[10] ITU-T Recommendation G.707: "Network node interface for the synchronous digital hierarchy
(SDH)".
[11] ITU-T Recommendation G.803: "Architecture of transport networks based on the synchronous
digital hierarchy (SDH)".
[12] ITU-T Recommendation G.804: "ATM cell mapping into plesiochronous digital hierarchy (PDH)".
[13] ITU-T Recommendation G.805: "Generic functional architecture of transport networks".
[14] ITU-T Recommendation G.832: "Transport of SDH elements on PDH networks: Frame and
multiplexing structures".
[15] ITU-T Recommendation I.150: "B-ISDN asynchronous transfer mode functional characteristics".
[16] ITU-T Recommendation I.321: "B-ISDN protocol reference model and its application".
[17] ITU-T Recommendation I.326: "Functional architecture of transport networks based on ATM".
[18] ITU-T Recommendation I.361: "B-ISDN ATM layer specification".
[19] ITU-T Recommendation I.371: "Traffic control and congestion control in B-ISDN".
[20] ITU-T Recommendation I.432: "B-ISDN user-network interface - Physical layer specification".
[21] ITU-T Recommendation I.432.1: "B-ISDN user-network interface - Physical layer specification:
General characteristics".
[22] ITU-T Recommendation I.432.2: "B-ISDN user-network interface - Physical layer specification:
155 520 kbit/s and 622 080 kbit/s operation".
[23] ITU-T Recommendation I.610: "B-ISDN operation and maintenance principles and functions".
[24] ITU-T Recommendation I.732: "Functional characteristics of ATM equipment".
3 Definitions, abbreviations and symbols
3.1 Definitions
For the purposes of the present document, the terms and definitions given in EN 300 417-1-1 [9] apply.
3.2 Abbreviations
For the purposes of the present document, the following abbreviations apply:
3.2.1
Modelling specific abbreviations
A Adaptation function
a consequent action
AI Adapted Information
AP Access Point
APId Access Point Identifier
C Connection function
c defect cause
CI Characteristic Information
CK ClocK
CP Connection Point
D Data
d defect correlation
ETSI
8 EN 301 163-2-1 V1.1.2 (1999-05)
G Group
L Layer
m monitoring function
MI Management Information
P12s 2 048 kbit/s PDH path layer with synchronous 125 ms frame structure
P31s 34 368 kbit/s PDH path layer with synchronous 125 ms frame structure
RI Remote Information
S Segment
S4 VC-4 path layer
Sk Sink
So Source
SSF Server Signal Fail
T Traffic management
TI Timing Information
TT Trail Termination function
vc virtual channel
vp virtual path
3.2.2
General abbreviations
AAL ATM Adaptation Layer
ACS ATM Cell Start
AIS Alarm Indication Signal
ATM Asynchronous Transfer Mode
BRPM Backward Report Performance Monitoring
CBDS Connectionless Broadband Data Service
CC Continuity Check
CCAD Continuity Check Activation/Deactivation
CLP Cell Loss Priority
CNGI CoNGestion Indication
dLCD Loss of Cell Delineation defect
EFCI Explicit Forward Congestion Indicator
EMF Element Management Function
F_DS Far-end Defect Second
FS Frame Start signal
GFC Generic Flow Control
HDLC High-level Data Link Control procedure
HEC Header Error Check
Hex Hexadecimal
ID IDentifier
LAN Local Area Network
LB LoopBack
LLID Loopback Location IDentifier
LOC Loss of Continuity
MA Maintenance and Adaptation
N_DS Near-end Defect Second
NE Network Element
N-ISDN Narrowband Integrated Services Digital Network
NNI Network Node Interface
NPC Network Parameter Control
OAM Operation, Administration and Maintenance
OCD Out of Cell Delineation
PDH Plesiochronous Digital Hierarchy
PLM PayLoad Mismatch
PM Performance Monitoring
PMAD Performance Monitoring Activation/Deactivation
POH Path OverHead
PRM Protocol Reference Model
PTI Payload Type Identifier
QoS Quality Of Service
ETSI
9 EN 301 163-2-1 V1.1.2 (1999-05)
RDI Remote Defect Indicator
RLCD Remote Loss of Cell Delineation
SDH Synchronous Digital Hierarchy
SLOC Segment Loss Of Continuity
SSF Server Signal Fail
TP Timing Point
TP Transmission Path
TSF Trail Signal Fail
UNI User Network Interface
UPC Usage Parameter Control
VC Virtual Channel
VC Virtual Container
VCC Virtual Channel Connection
VP Virtual Path
VPC Virtual Path Connection
VPI Virtual Path Identifier
3.3 Symbols and diagrammatic conventions
For the purposes of the present document, the symbols and diagrammatic conventions described in EN 300 417-1-1 [9]
apply.
3.4 Introduction
The atomic functions used in the Transmission Path (TP) convergence, ATM Virtual Path (VP) and Virtual Channel
(VC) Layer Networks and their associated Adaptation functions are defined in the present document.
The document is structured in the following manner:
• Transmission Path to Avp Adaptation Functions:
- SDH Adaptation Functions;
- Cell Based Adaptation Functions;
- PDH Adaptation Function.
• VP Layer Network, including Connection, Trail Termination, Segment, Traffic Management, Monitoring and
Loopback Functions;
• Avp to Avc Adaptation Functions;
• VC Layer Network, including Connection, Trail Termination, Segment, Traffic Management, Monitoring and
Loopback Functions;
• Avc to ATM Client Layer Adaptation Functions.
The Layer Networks and Adaptation functions are defined for the purpose of the user to group them into a higher level
grouping, if required. The decomposition of the atomic function sequence into Layer Networks and Adaptation functions
correspond to the view of ITU-T Recommendation G.805 [13]. It also represents the common basis view from the
Synchronous Digital Hierarchy (SDH) and ATM history perspective, since ITU-T Recommendation G.803 [11]
(defining SDH networks) as well as ITU-T Recommendation I.326 [17] (defining ATM networks) are both based on
ITU-T Recommendation G.805 [13].
For the SDH view, the grouping used in ITU-T Recommendation G.803 [11] is the Network Layer (or simply called
Layer). It associates the Layer Network and the Adaptation function in Client Layer direction into the grouping called
"Network Layer".
For the ATM view, the grouping used in ITU-T Recommendation I.326 [17] is the Transport Assembly, also called VP
Level resp. VC Level. It associates the Layer Network and the Adaptation function in Server direction into the grouping
called respectively "VP Level" and "VC Level".
ETSI
10 EN 301 163-2-1 V1.1.2 (1999-05)
Figure 1 shows the grouping of the Adaptation function to the Layer Network according to the two views.
.
SDH view Atom ics G.805 ATM view
G.803 I.326
Avc/XXX
Avc
Avc
Avp/Avc
Avp
Avp
TP/A vp
Figure 1: Different views for the grouping of the adaptation functions
ETSI
TP Layer Avp Layer Avc Layer
Avc Layer Network
Avp Layer N etwork
VP Level VC Lev el
11 EN 301 163-2-1 V1.1.2 (1999-05)
4 Transmission path to ATM virtual path adaptation
functions
4.1 S3 path adaptation functions
4.1.1 S3 path to ATM virtual path adaptation source function
S3/Avp_A_So
Symbol:
Avp_CI
S3/Avp
S3_T I
S3/Avp_A_So_MI
S3/Avp_RI
.
S3_AI
Figure 2: S3/Avp_A_So symbol
Interfaces:
Table 1: S3/Avp_A_So input and output signals
Input(s) Output(s)
per Avp_CI for each VP configured: S3_AI_D
Avp_CI_D S3_AI_CK
Avp_CI_ACS S3_AI_FS
Avp_CI_SSF
S3_TI_CK
S3_TI_FS
S3/Avp_RI_RLCD
S3/Avp_A_So_MI_Active
S3/Avp_A_So_MI_CellDiscardActive
S3/Avp_A_So_MI_TPusgActive
S3/Avp_A_So_MI_GFCActive
S3/Avp_A_So_MI_VPI-KActive
The S3/Avp_A_So function provides adaptation from the ATM Virtual Path to the VC-3 path. This is performed by a
grouping of Specific Processes and Common Processes as shown in figure 3.
Activation: The function shall access the access point when it is activated (MI_Active is true). Otherwise, it shall not
access the access point.
ETSI
12 EN 301 163-2-1 V1.1.2 (1999-05)
Avp_CI Avp_CI Avp_CI
N
VPI=0 VPI=1 VPI=2 -1 Specific
processes
.
Common
processes
S3/Avp_A_So
S3_AI
Figure 3: S3/Avp_A_So atomic function decomposed into Specific and Common processes parts
NOTE 1: The sequential order of the processes within the atomic functions is important. For the correct order, refer
to the ordering of the processes given below.
Specific Processes:
These Processes include VPI setting as well as VP asynchronous multiplexing. Each of these Specific Processes is
N
characterized by the Virtual Path Identifier number K, where 0 £ K £ 2 - 1.
VPI-K Activation: The Specific Processes perform the operation specified below when it is activated (MI_VPI-KActive
is true).
The format of the Characteristic Information (Avp_CI) is given in figure 4.
Cell Header
VPI=K
VPI=K VPI=K VPI=K
CI_ACS CI_ACS CI_ACS CI_ACS
Bit Header O ctet
1 2 3 4 5 6 7 8
VPI 1
VPI
CLP 4
Figure 4: Avp_CI (NNI format)
VPI setting is based on the activation of the Specific function by MI_VPI-KActive and inserts the value of "K" as VPI.
NOTE 2: The value of N represents the number of bits in the VPI field and is an integer number. Its maximum value
is equal to 12 for the ATM NNI. Its maximum value is equal to 8 for the ATM UNI.
VP multiplexing: Asynchronous multiplexing is performed for each active Specific function.
ETSI
13 EN 301 163-2-1 V1.1.2 (1999-05)
Common Processes:
The Common Processes include: Congestion control (selective cell discard (CLP based)), GFC processing, TP usage
measurement, cell rate decoupling, HEC processing, cell information field scrambling, cell stream mapping and
processing of the payload specific bytes C2 and H4, as well as bits 6 and 7 of G1, to the VC-3 Path OverHead (POH).
The logical ordering of the processes from input to output shall be maintained.
Bit Header O ctet
1 2 3 4 5 6 7 8
GFC
HEC
Figure 5: Cell header information processed in S3/Avp_A_So
12 85
4  ATM Cell
Figure 6: ATM cell stream mapping into Container-3 structure
12 3 85
3C2
4G1
(5-7)
5 VC-3 payload ( 9x84 bytes )
6H4
Figure 7: S3_AI_So_D
ETSI
14 EN 301 163-2-1 V1.1.2 (1999-05)
Congestion control: If enabled by MI_CellDiscardActive, this function shall perform selective cell discard according to
CLP value. In the event of congestion, cells with CLP = 1 are subject to be discarded prior to cells with CLP = 0. See
EN 300 301 [5] (ITU-T Recommendation I.371 [19]) for further details about the use of the CLP. In the event of
congestion, the Explicit Forward Congestion Indicator (EFCI) marking in the Payload Type Identifier (PTI) field is set
according to ETS 300 298-2 [3] (ITU-T Recommendation I.361 [18]).
GFC processing: The support of the GFC protocol applies to the UNI and in point-to-point configuration only and is an
option. The GFC function uses assigned and unassigned cells. Two modes of operation are available: Uncontrolled
Transmission (MI_GFCActive = false) and Controlled Transmission (MI_GFCActive = true). If enabled by
MI_GFCActive = true, this function shall insert the GFC protocol in the GFC field. The GFC field processing is defined
in ETS 300 298-1 [2] (ITU-T Recommendation I.150 [15]) and ETS 300 298-2 [3]
(ITU-T Recommendation I.361 [18]). If the GFC function is not supported or the GFC function disabled by
MI_GFCActive = false, the binary contents of the GFC field shall be set to "0000". In Uncontrolled Transmission mode,
neither the controlling nor the controlled Network Element (NE) performs the GFC procedure.
NOTE 3: The application of the GFC function in the ETSI environment is for further study.
TP usage measurement: The function shall count the transmitted cells for cell measurement purposes. This cell counting
shall be activated/deactivated by MI_TPusgActive.
Cell rate decoupling: This process takes the ATM cell stream present at its input and inserts it into the synchronous
container having a capacity of 765 bytes adding fixed stuff idle cells. The idle cells format is specified in
ETS 300 298-2 [3]. The cell rate decoupling process makes use of the VC-3 timing clock, frame position (S3_TI), and
idle cell generator.
HEC Processing: The HEC value for each cell is calculated and inserted into the HEC field. The method of HEC value
calculation shall be according to ETS 300 300 [4] (ITU-T Recommendation I.432.1 [21]).
Cell information field scrambling: The self synchronizing scrambler polynomial x + 1 has been identified for the
SDH-based transmission paths and minimizes the error multiplication introduced by the self synchronizing scrambling
process. It scrambles the information field bits only. The operation of the scrambler shall be according to
ETS 300 300 [4], subclause 10.5.3 (ITU-T Recommendation I.432.1 [21], subclause 4.3.4).
Cell stream mapping: The octet structure of ATM cells shall be aligned with the octet structure of Container-3 as shown
in figure 6.
Processing of the payload specific bytes:
H4: This payload dependent byte is not used for the mapping of ATM cells into VC-3. The contents of this byte shall be
00Hex.
G1: Bits 5, 6 and 7 of this byte are used to signal RLCD to the remote end. However, bits 5-7 may be overwritten by the
server layer (TP). Refer to table 4 of ITU-T Recommendation I.432.2 [22].
NOTE 4: For backward compatibility with equipment complying with the 1993 version of
ITU-T Recommendation I.432.1 [21], old equipment may use "100" or "111" codes in bits 5-7 of G1 to
indicate a Remote Loss of Cell Delineation (RLCD).
NOTE 5: Up to date, no application for the RLCD indication in G1 byte was found. However, in order to maintain
compatibility with ITU-T, the RLCD indication has to be set in source direction; it will be ignored in sink
direction.
C2: In this byte the function shall insert code "0001 0011" (ATM mapping) as defined in ETS 300 147 [1].
Defects: None.
Consequent Actions:
On declaration of RI_RLCD, the function shall output RLCD (pattern "010" in bits 5-7 of G1 byte) within x ms; on
clearing of RI_RLCD the function shall clear the RLCD indication defined in this byte within x ms.
NOTE 6: The value of x is for further study. Refer to the processing of RLCD.
ETSI
15 EN 301 163-2-1 V1.1.2 (1999-05)
Defect Correlations: None.
Performance Monitoring:
The use of the Performance Monitoring parameters are for further study. The parameters for the following functions
need to be defined:
• TP usage measurement;
• Count of discarded cells from congestion control.
4.1.2 S3 path to ATM virtual path adaptation sink function S3/Avp_A_Sk
Symbol:
A vp_C I
S3/Avp_A_Sk_M I S3/Avp S3/Avp_RI
.
S3_AI
Figure 8: S3/Avp_A_Sk symbol
Interfaces:
Table 2: S3/Avp_A_Sk input and output signals
Input(s) Output(s)
S3_AI_D per Avp_CI, for each VP configured:
S3_AI_CK Avp_CI_D
S3_AI_FS Avp_CI_ACS
S3_AI_TSF Avp_CI_SSF
Avp_CI_CNGI
S3/Avp_A_Sk_MI_Active
S3/Avp_A_Sk_MI_CellDiscardActive S3/Avp_RI_RLCD
S3/Avp_A_Sk_MI_TPusgActive
S3/Avp_A_Sk_MI_VPIrange S3/Avp_A_Sk_MI_cPLM
S3/Avp_A_Sk_MI_HECactive S3/Avp_A_Sk_MI_cLCD
S3/Avp_A_Sk_MI_GFCActive
S3/Avp_A_Sk_MI_DFLOC
S3/Avp_A_Sk_MI_VPI-KActive
Processes:
The S3/Avp_A_Sk function provides adaptation from the VC-3 Path to the ATM Virtual Path. This is performed by a
grouping of Specific Processes and Common Processes as shown in figure 9.
Activation: The S3/Avp_A_Sk function shall perform the Common and Specific Processes operation specified below
when it is activated (MI_Active is true). Otherwise, it shall activate the SSF signals at its output (CI_SSF) and not report
its status via the management point.
ETSI
16 EN 301 163-2-1 V1.1.2 (1999-05)
Avp_CI Avp_CI Avp_CI
N
VPI=0 VPI=1 VPI=2 -1 Specific
processes
.
Common
processes
S3/Avp_A_Sk
S3_AI
Figure 9: S3/Avp_A_Sk atomic function decomposed into Specific and Common Processes parts
NOTE 1: The sequential order of the processes within the atomic functions is important. For the correct order, refer
to the ordering of the processes given below.
Common Processes:
These Common Processes include: Handling of the payload specific bytes (C2, H4 and G1), demapping, cell
delineation, cell information field descrambling, HEC processing, cell rate decoupling, TP usage measurement, header
verification, GFC processing, VPI verification and congestion control (selective cell discard (CLP based)). The logical
ordering of these processes from input to output shall be maintained.
Handling of payload specific bytes:
C2: The function shall compare the contents of the accepted C2 byte with the expected value code "0001 0011" (ATM
mapping) as a check on consistency between the provisioning operation at each end. The application, acceptance and
mismatch detection processes are described in EN 300 417-1-1 [9], subclauses 7.2 and 8.2.1.
H4: This payload dependent byte is not used for this mapping and the receiver shall ignore its contents.
G1: The use of the information for RLCD in bits 6-7 is not defined. The receiver shall ignore its contents.
Demapping: The cell stream shall be extracted from C-3 container in the S3_AI in accordance with ETS 300 147 [1]
(ITU-T Recommendation G.707 [10]).
Cell Delineation: Loss of Cell Delineation defect (dLCD) shall be declared if an incorrect HEC is obtained ALPHA
times consecutively. dLCD shall be cleared if the cell delineation algorithm enters SYNC state. (According to
subclause 10.5.1.1, item 3 of ETS 300 300 [4], (subclause 4.3.3.2 of ITU-T Recommendation I.432.1 [21])).
Cell information field descrambling: The self synchronizing descrambler polynomial x + 1 has been identified for the
SDH-based transmission paths and minimizes the error multiplication introduced by the self synchronizing scrambling
process (factor 2). It descrambles the information field bits only. The operation of the descrambler in relation to the
HEC cell delineation state diagram shall be according to ETS 300 300 [4], subclause 10.5.3
(ITU-T Recommendation I.432.1 [21], subclause 4.3.4).
HEC Processing: HEC verification and correction shall be according to ETS 300 300 [4]
(ITU-T Recommendation I.432.1 [21]). Cells determined to have an invalid and incorrectible HEC pattern shall be
discarded. A count of invalid HEC events and a count of invalid HEC cell discard events are maintained with threshold
crossings checked. HEC correction mode may be activated/deactivated by MI_HECactive. The HEC correction mode
should be activated by default.
Cell rate decoupling: The function shall extract the Idle cells used as fixed stuff in the far-end S3/Avp adaptation source
function.
TP usage measurement: The function shall count the received cells for cell measurement purposes. This cell counting
shall be activated/deactivated by MI_TPusgActive.
ETSI
17 EN 301 163-2-1 V1.1.2 (1999-05)
Header verification: Invalid header patterns from paths based on SDH/PDH transmission systems are as follows (except
idle cell)(x = any value):
GFC VPI VCI PTI CLP
UNI xxxx all 0's all 0's xxx 1
VPI VCI PTI CLP
NNI all 0's all 0's xxx 1
GFC processing: The support of the GFC protocol applies to the UNI and in point-to-point configuration only and is an
option. The GFC function uses assigned and unassigned cells. Two modes of operation are available: Uncontrolled
Transmission (MI_GFCActive = false) and Controlled Transmission (MI_GFCActive = true). In Uncontrolled
Transmission mode, neither the controlling nor the controlled NE performs the GFC procedure. If enabled by
MI_GFCActive = true, this function shall extract the GFC protocol from the GFC field. The GFC field processing is
defined in ETS 300 298-1 [2] (ITU-T Recommendation I.150 [15]) and ETS 300 298-2 [3]
(ITU-T Recommendation I.361 [18]).
NOTE 2: The application of the GFC function in the ETSI environment is for further study.
NOTE 3: According to the Protocol Reference Model (PRM) (ETS 300 354 [7]
(ITU-T Recommendation I.321 [16])), the unassigned cells should be processed in the ATM layer. Some
of the ATM layer processes are adaptation processes belonging to the adaptation function between the TP
and the Avp layer network. The unassigned cells as well as idle cells are per physical connection
(VPI = 0, VCI = 0). For this reason the idle and unassigned cells processing is allocated to the same
atomic function.
VPI verification: The function shall verify that the received cell VPI is valid. If the VPI is determined to be invalid (i.e.
out-of-range VPI or not assigned), the cell shall be discarded. The range of valid VPI is given by MI_VPIrange.
Congestion control: If enabled by MI_CellDiscardActive, this function shall perform selective cell discard according to
CLP value. In the event of congestion, cells with CLP = 1 are subject to be discarded prior to cells with CLP = 0. See
EN 300 301 [5] (ITU-T Recommendation I.371 [19]) for further details about the use of the CLP. In the event of
congestion, the indication Avp_CI_CNGI is set for the traffic management function AvpT_TT_So to insert EFCI.
Specific Processes:
The function performs VP-AIS insertion and demultiplexing on a per VP basis.
VPI-K Activation: The Specific Processes perform the operation specified below when it is activated (MI_VPI-KActive
is true). Otherwise, it shall send no cells and Server Signal Fail (SSF) = false.
VP-AIS insertion: If the Specific Processes are activated, theVP-AIS insertion shall be performed as in the Consequent
Actions subclause.
VP demultiplexing: The adaptation sink function has access to a specific Avp identified by the number K
N
(0 £ K £ 2 - 1). When the function is activated only the cells of that specific Avp-K are passed in client direction.
NOTE 4: The value of N represents the number of bits in the VPI field and is an integer number. Its maximum value
is equal to 12 for the ATM NNI. Its maximum value is equal to 8 for the ATM UNI.
Defects:
The function shall detect for the dPLM defect according EN 300 417-1-1 [9], subclause 8.2.1 and for the dLCD defect
according to ETS 300 300 [4] (ITU-T Recommendation I.432.1 [21]).
Consequent Actions:
aCNGI‹"Event of Congestion" and CellDiscardActive.
ETSI
18 EN 301 163-2-1 V1.1.2 (1999-05)
aSSF‹dPLM or dLCD or AI_TSF.
aRLCD‹dLCD and (not AI_TSF) and (not dPLM).
aAIS‹dPLM or dLCD or AI_TSF.
On declaration of aAIS the function shall output VP-AIS Operation And Maintenance (OAM) cells on all active VPCs
according to ETS 300 404 [8] (ITU-T Recommendation I.610 [23], subclause 9.2.1.1.1.1); on clearing of aAIS the
generation of VP-AIS cells shall be stopped. If implemented, the defect type and defect location field (provided by
MI_DFLOC) of the VP-AIS cell shall be inserted in the information field. The contents of these fields is for further
study.
NOTE 5: Concerning the declaration of aRLCD, refer to note 6 of G1 byte setting in S3/Avp_A_So function.
Defect Correlations:
cPLM‹dPLM and (not AI_TSF).
cLCD‹dLCD and (not dPLM) and (not AI_TSF).
Performance Monitoring:
The use of the Performance Monitoring parameters are for further study. The parameters for the following functions
need to be defined:
• TP usage measurement;
• Count of discarded cells from congestion control;
• Count of invalid HEC events;
• Count of invalid HEC discard events;
• Count of invalid header discard events (one common counter for invalid header/invalid VPI/invalid Virtual
Channel Identifier (VCI) is maintained);
• OCD event.
4.2 S4 path adaptation functions
4.2.1 S4 path to ATM virtual path adaptation source function
S4/Avp_A_So
Symbol:
Avp_CI
S4/AvpG_A_So_MI
S4_TI
S4/Avp
S4/Avp_RI
.
S4_ AI
Figure 10: S4/Avp_A_So symbol
ETSI
19 EN 301 163-2-1 V1.1.2 (1999-05)
Interfaces:
Table 3: S4/Avp_A_So input and output signals
Input(s) Output(s)
per Avp_CI for each VP configured: S4_AI_D
Avp_CI_D S4_AI_CK
Avp_CI_ACS S4_AI_FS
Avp_CI_SSF
S4_TI_CK
S4_TI_FS
S4/Avp_RI_RLCD
S4/Avp_A_So_MI_Active
S4/Avp_A_So_MI_CellDiscardActive
S4/Avp_A_So_MI_TPusgActive
S4/Avp_A_So_MI_GFCActive
S4/Avp_A_So_MI_VPI-KActive
Processes:
The S4/Avp_A_So function provides adaptation from the ATM Virtual Path layer to the VC-4 path. This is performed
by a grouping of Specific Processes and Common Processes as shown in figure 11.
Activation: The function shall access the access point when it is activated (MI_Active is true). Otherwise, it shall not
access the access point.
Avp_CI Avp_CI Avp_CI
N
VPI=0 VPI=1 VPI=2 -1 Specific
processes
.
Common
processes
S4/Avp_A_So
S4_AI
Figure 11: S4/Avp_A_So atomic function decomposed
into Specific and Common processes parts
NOTE 1: The sequential order of the processes within the atomic functions is important. For the correct order, refer
to the ordering of the processes given below.
Specific Processes:
These Processes include VPI setting as well as VP asynchronous multiplexing. Each of these Specific Processes is
N
characterized by the Virtual Path Identifier number K, where 0 £ K £ 2 - 1.
VPI-K Activation: The Specific Processes perform the operation specified below when it is activated (MI_VPI-KActive
is true).
The format of the Characteristic Information (Avp_CI) is given in figure 12.
ETSI
20 EN 301 163-2-1 V1.1.2 (1999-05)
Cell Header
VPI=K VPI=K VPI=K VPI= K
CI_ACS CI_ACS CI_ACS CI_ACS
Bit Heade
...