ETSI ETS 300 399-1 ed.1 (1995-03)

Frame relay services; Part 1: General description

DE/NA-023216-1

Storitev blokovnega posredovanja – 1. del: Splošni opis

General Information

• Status: Published
• Publication Date: 28-Mar-1995
• Technical Committee: NA 2 - Numbering, Addressing, Routeing & Interworking
• Current Stage: 12 - Completion
• Due Date: 06-Apr-1995
• Completion Date: 29-Mar-1995
• Ref Project: SIST ETS 300 399-1 E1:2003 - Frame relay services; Part 1: General description

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 399-1 E1:2003
01-december-2003
Storitev blokovnega posredovanja – 1. del: Splošni opis
Frame relay services; Part 1: General description
Ta slovenski standard je istoveten z: ETS 300 399-1 Edition 1
ICS:
33.040.01 Telekomunikacijski sistemi Telecommunication systems
na splošno in general
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 399-1 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 399-1 E1:2003
EUROPEAN ETS 300 399-1
TELECOMMUNICATION March 1995
STANDARD
Source: ETSI TC-NA Reference: DE/NA-023216-1
ICS: 33.080
ISDN, frame relay, stage 1
Key words:
Frame relay services;
Part 1: General description
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

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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 .7
Introduction.7
1 Scope .9
2 Normative references.9
3 Definitions.10
4 Symbols and abbreviations .13
5 General definition .13
6 Description of the frame relay service.13
6.1 General description.13
6.1.1 Characteristics of the frame relay service .13
6.1.2 Core functions .14
6.2 Applications.15
7 Service classes .15
7.1 Layer 2 characteristics.15
7.1.1 Layer 2 permanent .15
7.1.2 Layer 2 on-demand case A .15
7.1.3 Layer 2 on-demand case B .15
7.2 Layer 1 characteristics.16
7.2.1 Layer 1 permanent .16
7.2.2 Layer 1 on-demand .16
8 Procedures.16
8.1 Provision/withdrawal .16
8.2 Normal procedures, invocation and operation .16
8.2.1 On-demand virtual circuit procedures .16
8.2.1.1 Originating the service (call set-up) .17
8.2.1.2 Indications during call set-up .17
8.2.1.3 Terminal selection/identification .17
8.2.1.4 Call notification .17
8.2.1.5 Synchronization between C-plane and U-plane.17
8.2.1.6 Terminating the virtual circuit (call clearing) .18
8.2.2 Permanent virtual circuit procedures.18
8.2.2.1 Layer 1 activation/establishment .18
8.2.2.2 Terminal selection/identification .18
8.2.2.3 Virtual circuit establishment.18
8.2.2.4 Terminating the virtual circuit.18
8.2.3 Data transfer.18
8.2.3.1 Regular procedures .18
8.2.3.2 Congestion management and control.19
8.3 Exceptional procedures, invocation and operation .20
8.3.1 On-demand virtual circuit .20
8.3.2 Permanent virtual circuit.20
9 Network capabilities for charging .20
10 Interworking.20
11 Attributes and values of attributes.20

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12 Dynamic description . 21
13 Numbering plan . 21
Annex A (normative): Support of the OSI network layer service . 22
A.1 General. 22
A.2 Connection establishment and release . 22
A.3 Data transfer. 23
A.4 Interworking . 23
A.5 Co-ordination of C-plane and U-plane. 23
Annex B (normative): Core service description . 24
Introduction . 24
B.1 Definitions. 24
B.1.1 OSI reference model definitions. 24
B.1.2 Service conventions definitions. 24
B.2 Definition of the core service . 25
B.2.1 Scope . 25
B.2.2 Overview of the core service. 25
B.2.3 Features of the core service. 25
B.2.4 Model of the core service . 26
B.2.4.1 Core connection endpoint identification. 26
B.2.4.2 Model of the core connection. 26
B.2.4.3 Queue model concepts. 26
B.2.4.4 Core connection establishment . 27
B.2.4.5 Data transfer. 27
B.2.4.6 Core connection release. 27
B.2.5 Sequence of primitives at one core connection endpoint. 27
B.2.6 Data transfer primitives . 27
B.2.6.1 Service primitives and parameters . 28
B.2.6.1.1 Primitives: Core-DATA-request and
Core-DATA-indication . 28
B.2.6.1.2 Parameters . 28
B.2.6.1.2.1 Core-user-data . 28
B.2.6.1.2.2 Congestion . 28
B.2.6.1.2.3 Discard eligibility. 28
B.2.6.1.2.4 Core service user protocol control
information . 29
B.2.6.1.3 Sequence of primitives. 29
B.2.7 Quality of service. 29
B.2.7.1 Throughput . 30
B.2.7.2 Transit delay . 30
Annex C (normative): Congestion management for the frame relay service. 31
C.1 Congestion management principles . 31
C.1.1 Scope . 31
C.1.2 Objectives of congestion management. 31
C.1.3 Requirements of congestion control mechanisms . 32
C.1.4 Congestion management strategy . 32
C.1.4.1 Congestion control mechanisms . 33
C.1.4.1.1 Explicit congestion notification . 33
C.1.4.1.2 Discard eligibility. 33
C.1.4.2 Network response to congestion . 33
C.1.4.3 User response to congestion. 34

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C.1.4.3.1 Terminals employing destination controlled transmitters.35
C.1.4.3.2 Terminals employing source controlled transmitters .35
Annex D (informative): Bibliography.38
History.39

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Foreword
This European Telecommunication Standard (ETS) has been produced by the Network Aspects (NA)
Technical Committee of the European Telecommunications Standards Institute (ETSI).
The content of this ETS is adapted from the CCITT Recommendation I.233.1 [2].
This ETS consists of 4 parts as follows:
Part 1: "Part 1: General description".
Part 2: "Part 2: Integrated Services Digital Network (ISDN); Frame relay bearer service; Service
definition".
Part 3: "Part 3: Integrated Services Digital Network (ISDN); Frame relay data transmission service;
Service definition".
Part 4: "Part 4: Broadband Integrated Services Digital Network (B-ISDN); Frame relay bearer
service; Service definition".
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
Introduction
The purpose of this ETS is to describe the frame relay service. The definition and description of this
service forms the basis to define the network capabilities required for the support of the service. The
prose description begins with clause 5, the static description begins with clause 11. No dynamic
description is provided.

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1 Scope
This European Telecommunication Standard (ETS) specifies the general aspects of the frame relay
service that is common to all frame relay services independent of the network on which the service is
offered.
This ETS is applicable for all network-specific frame relay service definitions.
This ETS should be complemented with standards for the network-specific part of the frame relay service.
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] CCITT Recommendation E.164: "Numbering plan for the ISDN era".
[2] CCITT Recommendation I.233.1: "ISDN frame relaying bearer service".
[3] ITU-T Recommendation I.500: "General structure of the ISDN Interworking
Recommendations".
[4] CCITT Recommendation Q.922: "ISDN data link layer specification for frame
mode bearer services".
[5] ITU-T Recommendation Q.933: "Layer 3 signalling specification for frame mode
bearer service".
[6] ITU-T Recommendation X.25: "Interface between data terminal equipment
(DTE) and data circuit-terminating equipment (DCE) for terminals operating in
the packet mode and connected to public data networks by dedicated circuit".
[7] ITU-T Recommendation X.31: "Support of packet mode terminal equipment by
an ISDN".
[8] CCITT Recommendation X.121: "International numbering plan for public data
networks".
[9] ITU-T Recommendation X.134: "Portion boundaries and packet layer reference
events: basis for defining packet-switched performance parameters".
[10] ITU-T Recommendation X.140: "General quality of service parameters for
communication via public data networks".
[11] CCITT Recommendation X.200: "Reference Model of Open Systems
Interconnection for CCITT applications".
[12] ITU-T Recommendation X.210: "Open Systems Interconnection layer service
definition conventions".
[13] ITU-T Recommendation X.213: "Information technology - Network service
definition for Open Systems Interconnection".
[14] CCITT Recommendation X.300: "General principles for interworking between
public networks and between public networks and other networks for the
provision of data transmission services".
[15] Addendum 1 to ISO 8348 (1987): "Connectionless mode transmission".

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[16] ISO 8473: "Information processing systems - Data communications - Protocol
for providing the connectionless-mode network service".
3 Definitions
For the purposes of this ETS, the following definitions apply:
access rate: The data rate of the physical connection at the user-network interface. The speed of the
physical connection determines how much data (maximum rate) the end-user can inject into the network.
Forward Explicit Congestion Notification (FECN): See CCITT Recommendation Q.922 [4] for the full
definition.
Backward Explicit Congestion Notification (BECN): See CCITT Recommendation Q.922 [4] for the full
definition.
Consolidated Link Layer Management Message (CLLM): See CCITT Recommendation Q.922 [4] for
the full definition.
Committed Burst size (B ): The maximum committed amount of data a user may offer to the network
C
during a time interval T . B is negotiated at virtual circuit establishment.
C C
Committed rate measurement interval (T ): The time interval during which the user is allowed to send
C
only the committed amount of data (B ) and the excess amount of data (B ). T is computed.
C E C
Committed Information Rate (CIR): The information transfer rate which the network is committed to
transfer under normal conditions. The rate is averaged over a minimum increment of time T . CIR is
C
negotiated at virtual circuit establishment.
congestion management: This includes: network engineering; Operation, Administration and
Maintenance (OAM) procedures to detect the onset of congestion; and real time mechanisms to prevent
or recover from congestion. Congestion management includes, but is not limited to; congestion control,
congestion avoidance and congestion recovery, as defined below:
- congestion control: this refers to real-time mechanisms to prevent and recover from congestion
during periods of coincidental peak traffic demands or network overload conditions (e.g. resource
failures). Congestion control includes both congestion avoidance and congestion recovery
mechanisms;
- congestion avoidance: congestion avoidance procedures refer to procedures initiated at or prior
to the onset of mild congestion in order to prevent congestion from becoming severe. Congestion
avoidance procedures operate around and within the regions of mild congestion and severe
congestion;
- congestion recovery: congestion recovery procedures refer to procedures initiated to prevent
congestion from severely degrading the end-user perceived Quality of Service (QoS) delivered by
the network. These procedures are typically initiated when the network has begun to discard frames
due to congestion. Congestion recovery procedures operate around and within the region of severe
congestion.
core service: See CCITT Recommendation Q.922 [4], annex A for the full definition.
C-plane: The C-plane refers to the data exchanged across a user-network interface for establishment,
release, monitoring, etc. of virtual circuits that are carried out outside the virtual circuits' data transmission.
delivered duplicated frames: A frame D received by a particular destination user is defined to be a
duplicated frame if both of the following conditions are true:
- frame D was not generated by the source user;
- frame D is exactly the same as a frame that was previously delivered to that destination.

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delivered errored frames: A delivered frame is defined to be an errored frame when the values of one or
more of the bits in the frame is in error, or when some, but not all, bits in the frame are lost bits or extra
bits (i.e. bits which were not present in the original signal) have been inserted (see
ITU-T Recommendation X.140 [10]).
delivered out-of-sequence frames: Consider a sequence of frames F , F , F , . , F and assume that
1 2 3 n
F is transmitted first, F second, . , F last.
1 2 n
A delivered frame F is defined to be out-of-sequence if it arrives at the destination after any of the frames
i
F , F , . , F .
(i+1) (i+2) n
discard eligibility indicator: This indicates that a frame should be discarded in preference to other
frames in a congestion situation, when frames need to be discarded to ensure safe network operation and
to maintain the committed level of service within the network.
egress node: The node that supports the destination user-network interface.
Excess Burst size (B ): The maximum allowed amount of data by which a user can exceed B during a
E C
time interval T . This data (B ) is delivered in general with a lower probability than B . B is negotiated at
C E C E
virtual circuit establishment.
fairness: An attempt by the network to maintain the committed call parameters which the end-user
negotiated at call set-up time. An example of this would be first discarding the frames in excess of the CIR
and refusing to allow new call set-ups to occur prior to discarding committed data traffic.
information integrity: Information integrity is preserved when for all frames delivered by the network no
transmission errors have been detected.
ingress node: The node that supports the source user-network interface.
lost frames: A transmitted frame is declared to be a lost frame when the frame is not delivered to the
intended destination user within a specified timeout period, and the network is responsible for the non-
delivery (see ITU-T Recommendation X.140 [10]).
misdelivered frames: A misdelivered frame is a frame transferred from a source to a destination user
other than the intended destination user. It is considered inconsequential whether the information is
correct or incorrect in content (see ITU-T Recommendation X.140 [10]).
offered load: Refers to the frames offered to the network, by an end-user, to be delivered to the selected
destination. The information rate offered to the network could exceed the negotiated class of service
parameters.
residual error rate: The residual error rate is defined for frame relay services and the corresponding layer
services. The layer services corresponding to the frame relay services are characterized by the exchange
of Service Data Units (SDUs). For frame relay, SDUs are exchanged at the functional boundary between
the core functions of CCITT Recommendation Q.922 [4] and the end-to-end protocol implemented above
them. The network participates in this exchange by means of FPDUs.
The residual error rate for the frame relay layer service is defined as:
Total correct SDUs delivered
=−1
R
fr
Total offered SDUs
The residual error rate for frame relay is defined as:
Total correct SDUs delivered
=−1
R
fr
Total offered FPDUs
statistical guarantee on traffic parameters: The QoS level for committed traffic characterized by the
CIR, B , and T parameters may be guaranteed with a certain probability. The QoS level for excess traffic
C C
characterized by the supplementary parameter B may also be guaranteed with a certain probability.
E

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The values of these probabilities are network dependent.
These statistical guarantees may only be verified over an observation period which is:
- sufficiently long with respect to T ;
C
- constraining for the network; and
- significant for the user.
As an example, the "busy hour" (in terms of traffic load) of the network may be used for this purpose.
throughput: Throughput for a virtual circuit (see ITU-T Recommendation X.134 [9], figure 1/X.139) is the
number of data bits contained in the SDU of the frame successfully transferred in one direction across the
virtual circuit per unit time. Successful transfer means that, for each frame, no transmission errors have
been detected.
transit delay: Transit delay is defined only between pairs of section boundaries. Transit delay of a Frame
relay Protocol Data Unit (FPDU) starts at the time t at which the first bit of the FPDU crosses the first
1
boundary, and ends at the time t at which the last bit of the FPDU crosses the second boundary:
2
transit delay = t - t
2 1.
Transit delay for a virtual circuit is equal to the summation of the section delays.
Figure 1: International reference frame relay connection
U-plane: The U-plane refers to the data exchanged across a user-network interface for the data transfer
on one or more virtual circuits.
virtual circuit: The term "virtual circuit" refers to a layer 2 virtual circuit, i.e. a frame relay virtual circuit.

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4 Symbols and abbreviations
For the purpose of this ETS, the following symbols and abbreviations apply:
BECN Backward Explicit Congestion Notification
B-ISDN Broadband Integrated Services Digital Network
B Committed Burst size
C
B Excess Burst size
E
CEI Connection Endpoint Identifier
CIR Committed Information Rate
CLLM Consolidated Link Layer Management Message
CONS OSI Connection Oriented Network layer Service
CPDU Core Protocol Data Unit
CSAP Core Service Access Point
CSDU Core Service Data Unit
DLCI Data Link Connection Identifier
ECN Explicit Congestion Notification
FECN Forward Explicit Congestion Notification
FPDU Frame relay Protocol Data Unit
ISDN Integrated Services Digital Network
LAN Local Area Network
NSAP OSI Network Service Access Point
OAM Operation, Administration and Maintenance
OSI-NS OSI Network layer Service
PSPDN Packet Switched Public Data Network
QoS Quality of Service
SDU Service Data Unit
T Committed rate measurement interval
C
X.25 DTP ITU-T Recommendation X.25 [6] Data Transfer Protocol
5 General definition
The frame relay service provides the bi-directional transfer of data units (Core-Service Data Unit (CSDU))
from one user-network interface to another. The data units are routed through the network on the basis of
an attached label. This label is a logical identifier with local significance (termed Data Link Connection
Identifier (DLCI) in the protocol description). Per DLCI, the order of the data units is preserved from one
user-network interface to another.
The user-network interface allows for the establishment of multiple on-demand and/or permanent virtual
circuits to many destinations.
This service description shows how the OSI network layer service can be supported (see annex A).
6 Description of the frame relay service
6.1 General description
6.1.1 Characteristics of the frame relay service
The frame relay service has the following characteristics:
1) all C-plane procedures, if needed, are performed in a logically separate manner using protocol
procedures that are network dependent and are specified in the network specific frame relay
service definition (e.g. in ETS 300 399-2);
2) the U-plane procedures at layer 1 are network dependent. Layer 2 procedures are based on the
core functions as defined in annex B (see also subclause 6.1.2). These layer 2 core functions allow
for the statistical multiplexing of user information flows immediately above layer 1 functions.

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The frame relay service:
a) preserves the order of SDUs transmitted at one user-network interface when they are delivered at
the other end;
NOTE: Since the network does not support any procedure above the core functions, the
network cannot use information in the frame to preserve the order of SDUs.
Nevertheless, networks are implemented in such a way that the frame order is
...