SIST ETS 300 298-1 E1:2003

• Abstract:

  Definition of ATM cell structure and header functions as well as ATM layer specifications

• 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 300 298-1 ed.1 (1995-03) - Broadband Integrated Services Digital Network (B-ISDN); Asynchronous Transfer Mode (ATM); Part 1: B-ISDN ATM functional specification

SIST ETS 300 298-1 E1:2003 is the Slovenian adoption of ETSI ETS 300 298-1 Edition 1 for Broadband Integrated Services Digital Network (B-ISDN) Asynchronous Transfer Mode (ATM). It specifies the ATM cell structure, header functions, and the ATM layer behavior used on B-ISDN interfaces, including signaling and Operation And Maintenance (OAM) traffic.

What does SIST ETS 300 298-1 E1:2003 specify?

SIST ETS 300 298-1 E1:2003 gives the basic characteristics and functional specification of ATM, with this part focused on the ATM layer. It is Part 1 of a 2-part ETS, and it sits alongside Part 2, which covers the ATM layer specification in more detail.

The scope is practical: it describes how ATM cells are formed, identified, routed, and managed across the User-Network Interface (UNI) and Network Node Interface (NNI). Clause 5.2 states that service characteristics aspects are not covered.

The document is organized into:

• Clause 1 - Scope
• Clause 2 - Normative references
• Clause 3 - Abbreviations
• Clause 4 - Basic principles of ATM
• Clause 5 - ATM layer, with subclauses on connections, identifiers, VCCs, VPCs, management interactions, QoS, PT, CLP, and GFC

What are the key requirements of SIST ETS 300 298-1 E1:2003?

SIST ETS 300 298-1 E1:2003 treats ATM as a connection-oriented, fixed-cell transfer mode. The most important requirements are about cell format, connection identifiers, connection setup, header field use, and traffic handling.

Fixed cell structure

Clause 4 defines the ATM cell as a fixed-size block with a 5-octet header and a 48-octet information field, and this size stays constant at all reference points, including UNI and NNI. In practice, equipment must carry user payload transparently in the information field and process routing and control information in the header.

Connection identity and routing

Clause 5.1 explains that Virtual Path Identifiers (VPIs) and Virtual Channel Identifiers (VCIs) distinguish ATM connections. A VC is fully identified only by both VPI and VCI at an interface, while VCI values are preserved within a VPC and VPIs may change where VP links terminate. This matters for switches and cross-connects that translate identifiers.

UNI and NNI capacity

Clause 5.1.2.3 and 5.1.2.4 state that 24 bits are available for connection identification at the UNI and 28 bits at the NNI. The usable routing bits are negotiated at the UNI and established at installation at the NNI, with bit positions defined in ETS 300 298-2. Implementers must therefore align equipment configuration with the agreed identifier space.

VCC and VPC behavior

Clauses 5.1.3 and 5.1.4 say that VCCs and VPCs preserve cell sequence integrity and support QoS, traffic parameter negotiation, and usage monitoring. VCCs can be established as switched, semi-permanent, or permanent connections, and VPCs can be switched, permanent, or semi-permanent. This is important for provisioning calls and checking that offered traffic matches negotiated limits.

Reserved header values

Clause 5.1.3.3 reserves specific VCI values for unassigned cell identification, physical layer cell identification, meta-signalling, general broadcast signalling, point-to-point signalling, and F4 OAM flows. Clause 5.1.5 says cells reserved for the physical layer also have reserved whole-header values. These values are not available for ordinary user traffic.

Management, PT, CLP, and GFC

Clauses 5.3 and 5.4 define how ATM layer management uses the Payload Type (PT) field and cell payload for management information, how PT distinguishes user information from management cells, and how the Cell Loss Priority (CLP) bit marks lower-priority cells. Clause 5.4.4 defines Generic Flow Control (GFC) at the UNI for short-term overload control. In practice, these fields control how the network classifies cells, protects QoS, and manages congestion.

What terms does SIST ETS 300 298-1 E1:2003 define?

• Asynchronous Transfer Mode (ATM) - A packet-oriented transfer mode that uses asynchronous time division multiplexing and fixed-size cells.
• Virtual Channel Connection (VCC) - An ATM connection whose cells keep their sequence order across the connection.
• Virtual Path Connection (VPC) - A bundle of virtual channel links routed together as one higher-level ATM connection.
• Cell Loss Priority (CLP) - The header bit that marks cells as lower priority and more eligible for discard.
• Payload Type (PT) - The header field that indicates whether the payload carries user information or management information, and can also show congestion and ATM-layer user indication.
• Generic Flow Control (GFC) - The UNI mechanism used to control local traffic flow and help with short-term overload conditions.
• Operation And Maintenance (OAM) - The management functions and traffic used for ATM-layer operation, maintenance, and monitoring.

Who uses SIST ETS 300 298-1 E1:2003?

SIST ETS 300 298-1 E1:2003 is used by designers and operators of B-ISDN and ATM equipment, including switches, cross-connects, concentrators, terminal equipment, and customer premises networks. It is also relevant to engineers who configure UNI and NNI interfaces, signaling paths, OAM flows, QoS handling, and flow control. Quality and procurement teams use it to check that devices use the right header fields, reserved values, and connection rules.

What changed in SIST ETS 300 298-1 E1:2003 from the previous edition?

SIST ETS 300 298-1 E1:2003 corresponds to ETS 300 298-1 Edition 1, identified in the history as the first edition.

Which standards are used with SIST ETS 300 298-1 E1:2003?

• CCITT Recommendation I.150 - Defines B-ISDN ATM functional characteristics.
• CCITT Recommendation I.113 - Provides broadband ISDN vocabulary, including VC and VPC definitions.
• CCITT Recommendation I.311 - Covers general B-ISDN network aspects and signaling procedures.
• CCITT Recommendation I.610 - Gives B-ISDN OAM principles and functions.
• CCITT Recommendation I.371 - Covers traffic control and congestion control in B-ISDN.
• CCITT Recommendation I.413 - Defines the B-ISDN user-network interface.
• ETS 300 298-2 - Provides the ATM layer specification, including routing-bit positions and coded values for reserved VPI/VCI combinations.

What does the SIST ETS 300 298-1 E1:2003 document contain?

The document contains the ATM basics, the connection model, and the rules for identifying and routing cells with VPI and VCI. It also includes the functional treatment of VCCs and VPCs, reserved header values, and the way management information is carried.

Clause 5.4 groups the operational functions supported by the ATM layer: cell multiplexing and switching, QoS handling, CLP behavior, PT coding, and GFC at the UNI. The text also includes figure-based explanations of how VC and VP connections are identified and routed.

SLOVENSKI STANDARD
01-december-2003
âLURNRSDVRYQRGLJLWDOQRRPUHåMH]LQWHJULUDQLPLVWRULWYDPL%,6'1±$VLQKURQL
SUHQRVQLQDþLQ$70±2VQRYQH]QDþLOQRVWLLQIXQNFLMVNHVSHFLILNDFLMHVLVWHPD
$70±GHO)XQNFLMVNDVSHFLILNDFLMD]D%,6'1$70
Broadband Integrated Services Digital Network (B-ISDN); Asynchronous Transfer Mode
(ATM); Part 1: B-ISDN ATM functional specification
Ta slovenski standard je istoveten z: ETS 300 298-1 Edition 1
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 300 298-1
TELECOMMUNICATION March 1995
STANDARD
Source: ETSI TC-NA Reference: DE/NA-052613-1
ICS: 33.080
Broadband, ISDN, ATM
Key words:
Broadband Integrated Services Digital Network (ISDN);
Asynchronous Transfer Mode (ATM);
Basic characteristics and functional specification of ATM;
Part 1: B-ISDN ATM functional specification
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 1995. All rights reserved.
New presentation - see History box

Page 2
ETS 300 298-1: March 1995
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

Page 3
ETS 300 298-1: March 1995
Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Abbreviations.7
4 Basic principles of ATM.8
5 ATM layer .8
5.1 ATM layer connections .8
5.1.1 Connection definition.8
5.1.2 Connection identifiers.9
5.1.2.1 Virtual Path Identifiers (VPIs) and Virtual Channel
Identifiers (VCIs).9
5.1.2.2 VPI - VCI relationships.9
5.1.2.3 Number of active connections at the UNI.9
5.1.2.4 Number of active connections at the NNI.9
5.1.3 Aspects of VCCs .10
5.1.3.1 General characteristics of VCCs .10
5.1.3.2 Establishment and release of a VCC.10
5.1.3.2.1 Establishment/release at the UNI .10
5.1.3.2.2 Establishment/release at the NNI .11
5.1.3.3 Pre-assigned VCIs.11
5.1.3.4 Signalling VCs .11
5.1.3.5 OAM VCs.11
5.1.4 Aspects of VPCs .11
5.1.4.1 General characteristics of VPCs.11
5.1.4.2 Establishment and release of a VPC.12
5.1.4.3 Pre-assigned VPIs.12
5.1.5 Pre-assigned cell header values .12
5.2 Service characteristics.12
5.3 Management plane interactions.12
5.4 Functions of the ATM layer.13
5.4.1 Cell multiplexing and switching .13
5.4.2 QoS provided by the ATM layer .13
5.4.2.1 QoS related to VCCs .13
5.4.2.2 QoS related to VPCs .13
5.4.2.3 QoS related to Cell Loss Priority (CLP) .13
5.4.2.3.1 General.13
5.4.2.3.2 CLP Indicator.14
5.4.3 PT functions .14
5.4.4 Generic Flow Control (GFC) at the UNI .14
History.16

Page 4
ETS 300 298-1: March 1995
Blank page
Page 5
ETS 300 298-1: March 1995
Foreword
This European Telecommunication Standard (ETS) has been produced by the Network Aspects (NA)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
Asynchronous Transfer Mode (ATM) is the transfer mode solution for implementing a Broadband
Integrated Services Digital Network (B-ISDN). It influences the standardisation of digital hierarchies,
multiplexing structures, switching and interfaces for broadband signals.
This ETS consists of 2 parts as follows:
Part 1: "B-ISDN ATM functional specification".
Part 2: "B-ISDN ATM layer specification".
Transposition dates
Date of latest announcement of this ETS (doa): 30 June 1995
Date of latest publication of new National Standard 31 December 1995
or endorsement of this ETS (dop/e):
Date of withdrawal of any conflicting National Standard (dow): 31 December 1995

Page 6
ETS 300 298-1: March 1995
Blank page
Page 7
ETS 300 298-1: March 1995
1 Scope
This European Telecommunication Standard (ETS) is a 2 Part ETS which gives the basic characteristics
and functional specification of Asynchronous Transfer Mode (ATM).
This part specifically addresses the functions of the ATM layer (see CCITT Recommendation I.150 [1]).
This layer is common to all services, including signalling and Operation And Maintenance (OAM).
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 I.150: "B-ISDN asynchronous transfer mode functional
characteristics".
[2] CCITT Recommendation I.113: "Vocabulary of terms for broadband aspects of
ISDN".
[3] CCITT Recommendation I.311: "B-ISDN general network aspects".
[4] CCITT Recommendation I.610: "B-ISDN Operation and Maintenance principles
and functions".
[5] CCITT Recommendation I.371: "Traffic control & congestion control in B-ISDN".
[6] CCITT Recommendation I.413: "B-ISDN user-network interface".
[7] ETS 300 298-2: "Network Aspects (NA); Basic characteristics and functional
specification of Asynchronous Transfer Mode (ATM) Part 2: B-ISDN ATM layer
specification".
3 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
AAL ATM Adaptation Layer
B-NT2 Broadband Network Termination 2
B-TE Broadband Terminal Equipment
CBR Constant Bit Rate
CLP Cell Loss Priority
GFC Generic Flow Control
NNI Network Node Interface
OAM Operation And Maintenance
PT Payload Type
QoS Quality of Service
TE Terminal Equipment
UNI User-Network Interface
VBR Variable Bit Rate
VC Virtual Channel
VCC Virtual Channel Connection
VCI Virtual Channel Identifier
VP Virtual Path
VPC Virtual Path Connection
VPI Virtual Path Identifier
Page 8
ETS 300 298-1: March 1995
4 Basic principles of ATM
ATM is used in this ETS for addressing a specific packet oriented transfer mode which uses
asynchronous time division multiplexing techniques. The multiplexed information flow is organized into
blocks of fixed size called cells. A cell consists of an information field and a header. The primary role of
the header is to identify cells belonging to the same Virtual Channel (VC) within the asynchronous time
division multiplex. Transfer capacity is assigned by negotiation and is based on the source requirements
and the available capacity. Cell sequence integrity on a Virtual Channel Connection (VCC) is preserved by
1)
the ATM layer .
ATM is a connection oriented technique. Connection identifiers are assigned to each link of a connection
when required and released when no longer needed. In general, signalling and user information are
carried on separate ATM connections.
ATM offers a flexible transfer capability common to all services, including connectionless services.
Additional functionalities above the ATM layer (e.g. in the ATM Adaptation Layer (AAL)) are provided to
accommodate various services. The boundary between the ATM layer and the AAL corresponds to the
boundary between functions supported by the contents of the cell header and functions supported by AAL
specific information. The AAL specific information is contained in the information field of the ATM cell.
The information field is transported transparently by the ATM layer. No processing, e.g. error control, is
performed on the information field at the ATM layer.
The header and information field each consist of a fixed integer number of octets. The header size,
(5 octets), and the information field size, (48 octets), remain constant at all reference points, including the
User-Network Interface (UNI) and the Network Node Interface (NNI), where the ATM technique is applied.
5 ATM layer
5.1 ATM layer connections
5.1.1 Connection definition
An ATM layer connection consists of the concatenation of ATM layer links in order to provide an
end-to-end transfer capability to access points.

) For a multipoint-to-point virtual connection, cell sequence integrity is preserved for cells from each VCC endpoint of the VCC.

Page 9
ETS 300 298-1: March 1995
5.1.2 Connection identifiers
5.1.2.1 Virtual Path Identifiers (VPIs) and Virtual Channel Identifiers (VCIs)
At a given interface, in a given direction, the different Virtual Path (VP) links multiplexed at the ATM layer
into the same physical layer connection are distinguished by the VPI. The different VC links in a Virtual
Path Connection (VPC) are distinguished by the VCI as indicated in figure 1.
Physical layer con nection
_ _ _ _ _ _ _ _
VCI .
a
.
_ _ _ _ _ _ _ _
VPI
x
.
VCI
b
_ _ _ _ _ _ _ _
_ _ _ _ _ _ _ _
VPI
y
NOTE: VCI and VCI represent two of the possible values of VCI within the VP link with the
a b
value VPI . Similarly, VPI and VPI refer to two of the possible values of VPI within the
x x y
physical layer connection.
Figure 1: ATM layer connection identifier
5.1.2.2 VPI - VCI relationships
Two different VCs belonging to two different VPs at a given interface may have the same VCI value.
Therefore, a VC is only fully identified at an interface by both VPI and VCI values.
A specific value of VCI has no end-to-end significance if the VCC is switched. VPIs may be changed
wherever VP links are terminated (e.g. cross-connects, concentrators and switches). VCIs may only be
changed where VC links are terminated. As a consequence, VCI values are preserved within a VPC.
5.1.2.3 Number of active connections at the UNI
At the UNI, 24 bits are available in the VPI/VCI field for connection identification. The actual number of
routeing bits in the VPI and VCI fields used for routeing is negotiated between the user and the network,
e.g. on a subscription basis. This number is determined on the basis of the lower requirement of the user
or the network. The rules to determine the position of the routeing bits used within the VPI/VCI field are
given in subclause 4.2.3 of ETS 300 298-2 [7].
NOTE: The number of VCI field routeing bits used in a user-to-user VP is negotiated between
the users of the VP.
5.1.2.4 Number of active connections at the NNI
At the NNI, 28 bits are available in the VPI/VCI field for connection identification. The actual number of
routeing bits in the VPI and VCI fields used for routeing is established at installation. This number is
determined on the basis of the requirement of each entity. The rules to determine the position of the
routeing bits used within the VPI/VCI field are given in subclause 4.3.2 of ETS 300 298-2 [7].

Page 10
ETS 300 298-1: March 1995
5.1.3 Aspects of VCCs
5.1.3.1 General characteristics of VCCs
The definition of a VCC is given in CCITT Recommendation I.113 [2]. This subclause provides additional
explanations to facilitate the understanding of the following topics:
a) Quality of Service (QoS): a user of a VCC is provided with a QoS specified by parameters such as
cell loss ratio and cell delay variation;
b) switched, semi-permanent and permanent VCCs: VCCs can be provided on a switched, semi-
permanent or permanent basis;
c) cell sequence integrity: cell sequence integrity is preserved within a VCC;
d) traffic parameter negotiation and usage monitoring: when a user requests from the network the
establishment of a VCC, traffic parameters shall be negotiated between a user and a network for
each VCC at VCC establishment and may be subsequently renegotiated. Input cells from the user
to the network may be monitored to ensure that the negotiated traffic parameters are not violated.
At a B-ISDN interface (e.g. UNI or NNI), there are two
...