ETSI ETS 300 201 ed.1 (1994-12)

Integrated Services Digital Network (ISDN); Call Forwarding No Reply (CFNR) supplementary service; Service description

T/NA1(89)23

Digitalno omrežje z integriranimi storitvami (ISDN) – Dopolnilna storitev: podaja klica, ko ni odziva (CFNR) – Opis storitve

General Information

• Status: Published
• Publication Date: 06-Dec-1994
• Technical Committee: NA 1 - User Interfaces, Services and Charging
• Current Stage: 12 - Completion
• Due Date: 28-Nov-1994
• Completion Date: 07-Dec-1994
• Ref Project: SIST ETS 300 201 E1:2003 - Integrated Services Digital Network (ISDN); Call Forwarding No Reply (CFNR) supplementary service; Service description

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ETS 300 201 E1:2003
01-december-2003
Digitalno omrežje z integriranimi storitvami (ISDN) – Dopolnilna storitev: podaja
klica, ko ni odziva (CFNR) – Opis storitve
Integrated Services Digital Network (ISDN); Call Forwarding No Reply (CFNR)
supplementary service; Service description
Ta slovenski standard je istoveten z: ETS 300 201 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
SIST ETS 300 201 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 201 E1:2003

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SIST ETS 300 201 E1:2003
EUROPEAN ETS 300 201
TELECOMMUNICATION December 1994
STANDARD
Source: ETSI TC-NA Reference: T/NA1(89)23
ICS: 33.080
ISDN, supplementary service
Key words:
Integrated Services Digital Network (ISDN);
Call Forwarding No Reply (CFNR) supplementary service
Service 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 1994. All rights reserved.
New presentation - see History box

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ETS 300 201: December 1994
Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to
"ETSI Editing and Committee Support Dept." at the address shown on the title page.

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Contents
Foreword .5
1 Scope .7
2 Normative references.7
3 Definitions.8
4 Symbols and abbreviations .9
5 Description .9
6 Procedures.9
6.1 Provision and withdrawal .9
6.2 Normal procedures .10
6.2.1 Activation, deactivation and registration.10
6.2.1.1 Activation .10
6.2.1.2 Deactivation.11
6.2.1.3 Registration.12
6.2.2 Erasure.12
6.2.3 Invocation and operation .12
6.2.3.1 Served user's view.12
6.2.3.2 Forwarded-to user's view.13
6.2.3.3 Calling user's view .13
6.2.4 Interrogation .14
6.3 Exceptional procedures .15
6.3.1 Activation, deactivation and registration.15
6.3.1.1 Activation .15
6.3.1.2 Deactivation.16
6.3.1.3 Registration.16
6.3.2 Erasure.17
6.3.3 Invocation and operation .17
6.3.4 Interrogation .17
7 Intercommunication considerations.18
7.1 Interworking with non-ISDNs .18
7.2 Interworking with private ISDNs.18
8 Interaction with other supplementary services .19
8.1 Advice of charge services.19
8.1.1 Charging information at call set-up time.19
8.1.2 Charging information during the call.19
8.1.3 Charging information at the end of the call.19
8.2 Call waiting.19
8.3 Call hold .19
8.4 Explicit call transfer.20
8.5 Number identification services.20
8.5.1 Calling line identification presentation .20
8.5.2 Calling line identification restriction .20
8.5.3 Connected line identification presentation.20
8.5.4 Connected line identification restriction.20
8.6 Closed user group.21
8.7 Completion of calls to busy subscriber .21
8.8 Conference services .21
8.8.1 Conference call, add-on .21
8.8.2 Meet me-conference .21

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8.9 Direct dialling in . 21
8.10 Diversion services . 22
8.10.1 Call forwarding unconditional. 22
8.10.2 Call forwarding busy . 22
8.10.3 Call forwarding no reply . 22
8.10.4 Call deflection . 22
8.11 Freephone. 22
8.12 Malicious call identification. 22
8.13 Multiple subscriber number . 23
8.14 Subaddressing . 23
8.15 Terminal portability. 23
8.16 Three party. 23
8.17 User-to-user signalling . 23
Annex A (informative): Interaction between user-to-user signalling and the CFNR supplementary
service. 25
History. 26

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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).
In accordance with CCITT Recommendation I.130 [1], the following three level structure is used to
describe the supplementary telecommunications services as provided by European public
telecommunications operators under the pan-European Integrated Services Digital Network (ISDN):
- Stage 1: is an overall service description, from the user's standpoint;
- Stage 2: identifies the functional capabilities and information flows needed to support the
service described in stage 1; and
- Stage 3: defines the signalling system protocols and switching functions needed to implement
the service described in stage 1.
This ETS details the stage 1 aspects (overall service description) for the Call Forwarding No Reply
(CFNR) supplementary service. The stage 2 and stage 3 aspects are detailed in ETS 300 205 (1994) and
ETS 300 207 (1994), respectively.
Proposed transposition dates
Date of latest announcement of this ETS (doa): 31 March 1995
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 September 1995
Date of withdrawal of any conflicting National Standard (dow): 30 September 1995

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1 Scope
This standard defines the stage one of the Call Forwarding No Reply (CFNR) supplementary service for
the pan-European Integrated Services Digital Network (ISDN) as provided by European public
telecommunications operators. Stage one is an overall service description from the user's point of view
(see CCITT Recommendation I.130 [1]), but does not deal with the details of the human interface itself.
This standard defines the interworking requirements of private ISDNs with the public ISDN.
In addition this standard specifies the base functionality where the service is provided to the user via a
private ISDN.
This standard does not specify the additional requirements where the service is provided to the user via a
telecommunications network that is not an ISDN but does include interworking requirements of other
networks with the public ISDN.
Interactions with supplementary services not listed in clause 8 are outside the scope of this standard.
Charging principles are outside the scope of this standard.
The CFNR supplementary service enables a served user to have the network redirect to another user
calls which are addressed to the served user's ISDN number, and for which the connection is not
established within a defined period of time. The CFNR supplementary service may operate on all calls, or
just those associated with specified basic services. The served user's ability to originate calls is unaffected
by the CFNR supplementary service.
The CFNR supplementary service is applicable to all circuit-switched telecommunication services.
This standard is applicable to the stage two and stage three standards for the ISDN CFNR supplementary
service. The terms "stage two" and "stage three" are also defined in CCITT Recommendation I.130 [1].
Where the text indicates the status of a requirement (i.e. as strict command or prohibition, as authorization
leaving freedom, or as a capability or possibility), this shall be reflected in the text of the relevant stage two
and stage three standards.
Furthermore, conformance to this standard is met by conforming to the stage three standards with the
field of application appropriate to the equipment being implemented. Therefore, no method of testing is
provided for this standard.
2 Normative references
This standard 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 standard only when incorporated in it by amendment or revision. For dated references the
latest edition of the publication referred to applies.
[1] CCITT Recommendation I.130 (1988): "Method for the characterization of
telecommunication services supported by an ISDN and network capabilities of
an ISDN".
[2] CCITT Recommendation I.112 (1988): "Vocabulary of terms for ISDNs".
[3] CCITT Recommendation E.164 (1991): "Numbering plan for the ISDN era".
[4] CCITT Recommendation I.210 (1988): "Principles of telecommunication
services supported by an ISDN and the means to describe them".
[5] CCITT Recommendation Q.9 (1988): "Vocabulary of switching and signalling
terms".

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3 Definitions
For the purpose of this standard the following definitions apply:
Integrated Services Digital Network (ISDN): See CCITT Recommendation I.112 [2], § 2.3, definition
308.
(basic) service; Telecommunications service: See CCITT Recommendation I.112 [2], § 2.2, definition
201.
supplementary service: See CCITT Recommendation I.210 [4], § 2.4.
ISDN number: A number conforming to the numbering plan and structure specified in CCITT
Recommendation E.164 [3].
served user: The user to whom the CFNR supplementary service is provided.
user A: The calling user in a call which is subject to diversion.
user B: The served user when a call (from user A) is subject to the CFNR supplementary service.
NOTE: In the context of multiple diversions, a suffix is used, e.g. 1, 2, . n, n+1, . m, to
denote the successive diverting users. For example, user B3 is also the diverted-to
user with respect to the diversion applied at user B2.
user C: The forwarded-to user in a call which is subject to the CFNR supplementary service. In the case
of a call which is subject to multiple diversions, user C is the forwarded-to user with respect to the final call
forwarding.
forwarded-to user: A user to whom the call is redirected as a result of forwarding.
diverted-to user: A user to whom a call is redirected as a result of diversion.
basic access: See CCITT Recommendation Q.9 [5], § 1, definition 1551.
primary rate access: See CCITT Recommendation Q.9 [5], § 1, definition 1552.
address: See CCITT Recommendation E.164 [3], § 12.
subaddress: See CCITT Recommendation E.164 [3], § 12.2.
(call) forwarding: A general term applied to any functionality whereby a call is redirected automatically by
the service provider to another user. The forms of forwarding are: unconditional, whereby all calls are
redirected; busy, whereby calls encountering busy are redirected; and, no reply, whereby calls which are
not answered within a time period are redirected.
diversion: A general term which includes all forms of forwarding, and includes deflection whereby calls
are redirected by the user instead of being answered.
basic call procedures: The procedures by which a call (as an instance of a basic telecommunication
service) is established and terminated.
diverting user: A user for whom the call is subjected to diversion.

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4 Symbols and abbreviations
CFNR Call Forwarding No Reply
ISDN Integrated Services Digital Network
PSTN Public Switched Telephone Network
5 Description
The CFNR supplementary service shall be available to users who are connected to the network via a
basic access or a primary rate access.
The CFNR supplementary service enables a served user to have the network redirect to another user
calls which are addressed to the served user's ISDN number, and for which the connection is not
established within a defined period of time. The CFNR supplementary service may operate on all calls, or
just those associated with specified basic services. The served user's ability to originate calls is unaffected
by the CFNR supplementary service.
The CFNR supplementary service can only be invoked by the network after the call has been offered to
the served user and an indication that the called user is being informed of the call has been received.
As a service provider option, a subscription option can be provided to enable the served user to receive an
indication that the CFNR supplementary service has been activated. This indication shall be provided
when the served user originates a call if the CFNR supplementary service has been activated for the
served user's ISDN number and for the basic service requested for the call.
The maximum number of diversions permitted for each call is a service provider option with an upper limit
of five diversions. When counting the number of diversions, all types of diversion are included.
6 Procedures
6.1 Provision and withdrawal
The CFNR supplementary service shall be provided after prior arrangement with the service provider.
As a service provider option, the CFNR supplementary service can be provided on a per ISDN number
basis, or the CFNR supplementary service can apply to the whole access. If a service provider offers both
of these options, then it shall be a subscription option to choose which of these options applies.
In addition, the CFNR supplementary service (including options) can be subscribed to for all basic
services subscribed to by the user, or as a service provider option, the user can identify particular basic
service(s) for which the CFNR supplementary service shall apply.
As a service provider option, the service can be offered with one or more of four subscription options,
which can apply separately to each basic service subscribed to. If the CFNR supplementary service is
provided on a per ISDN number basis, then these options can apply separately to each ISDN number. For
each subscription option, only one value can be selected. Subscription options are summarized in table 1.

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Table 1
Subscription options Value
Served user receives notification -no
that the call has been forwarded - yes
Calling user receives notification -no
that the call has been forwarded - yes, without the ISDN
number of the forwarded-to
user
- yes, with the ISDN number of
the forwarded-to user
Served user receives notification -no
that the CFNR supplementary - yes
service is currently activated
The served users ISDN number can-no
be presented to the forwarded-to - yes
user
The value of the no reply timer shall be set by the service provider as a default value applying for all users.
As a service provider option, a subscription option can be offered to served users, to enable the CFNR
supplementary service to be activated, deactivated and interrogated for all ISDN numbers on the same
access. ISDN numbers for which the CFNR supplementary service is not subscribed to shall not be
affected.
The CFNR supplementary service shall be withdrawn by the service provider upon request of the
subscriber or for service provider reasons.
6.2 Normal procedures
6.2.1 Activation, deactivation and registration
6.2.1.1 Activation
The served user shall supply the following information when requesting the activation of the CFNR
supplementary service:
- the ISDN number of the forwarded-to user, which can be accompanied by a subaddress for
additional identification of the forwarded-to user; and
- information as to whether the activation of the CFNR supplementary service is for all basic services
to which the CFNR supplementary service applies, or for a specific basic service out of the basic
services to which the CFNR supplementary service applies.

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When subscription applies on a per ISDN number basis and more than one ISDN number is allocated to
the access, then:
- the served user shall also supply the ISDN number for which the activation of the CFNR
supplementary service shall apply, or;
- as a service provider option, the served user can, if subscribed to, indicate that the activation of the
CFNR supplementary service shall apply for all ISDN numbers for which the CFNR supplementary
service is subscribed to. In this case, this activation shall replace any previous activation of the
CFNR supplementary service which may be in force on individual ISDN numbers on the access, for
the basic services indicated at activation.
When subscription applies for the whole access, or only one ISDN number is allocated to the access, the
served user need not provide an ISDN number to identify the served user. If the served user includes an
ISDN number allocated to that access, or indicates that the activation of the CFNR supplementary service
shall apply to all ISDN numbers (if this functionality is offered by the service provider and subscribed to by
the served user) then the ISDN number, or the indication of all ISDN numbers, shall be ignored. Activation
of the CFNR supplementary service shall proceed as normal.
The served user can separately activate the CFNR supplementary service for each basic service to which
the CFNR supplementary service applies and thereby request a different ISDN number and/or subaddress
to identify the forwarded-to user for each basic service to which the CFNR supplementary service applies.
When the CFNR supplementary service is activated for all basic services, this activation shall replace any
previous activation of the CFNR supplementary service which may be in force on individual basic services.
Verification of the ISDN number of the forwarded-to user can be carried out before accepting the request
to activate the CFNR supplementary service. This verification can be limited, e.g. a simple check of the
ISDN number of the forwarded-to user to see if the ISDN number is within the allowed number range.
When the served user's request to activate the CFNR supplementary service is accepted, the service
provider shall inform the served user. The information shall include the address of the forwarded-to user
to whom the served user has activated the CFNR supplementary service. All affected users shall be
informed.
6.2.1.2 Deactivation
The CFNR supplementary service can be deactivated in any of the following ways:
- the served user can request the deactivation of the CFNR supplementary service for individual
basic services. The service provider shall inform the served user that the previous activation of the
CFNR supplementary service has been deactivated. All affected users shall be informed;
- the served user can request the deactivation of the CFNR supplementary service for all basic
services. The service provider shall inform the served user that the previous activation of the CFNR
supplementary service has been deactivated. All affected users shall be informed;
- the served user can request the activation of the CFNR supplementary service indicating a basic
service for which the CFNR supplementary service has already been activated. This shall replace
the previous information registered for that basic service. In this case, users shall not be specifically
informed of the deactivation. The procedures of subclause 6.2.1.1 for informing the served user
apply;

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- the served user can request the activation of the CFNR supplementary service for all basic
services. This shall replace the information registered for all of the basic services for which the
CFNR supplementary service has already been activated. In this case, users shall not be
specifically informed of the deactivation. The procedures of subclause 6.2.1.1 for informing the
served user apply.
When subscription applies on a per ISDN number basis and more than one ISDN number is allocated to
the access, then:
- the served user shall also supply the ISDN number for which the deactivation of the CFNR
supplementary service shall apply, or;
- as a service provider option, the served user can, if subscribed to, indicate that the deactivation of
the CFNR supplementary service shall apply for all ISDN numbers for which the CFNR
supplementary service is subscribed to.
When subscription applies for the whole access, or only one ISDN number is allocated to the access, the
served user need not provide an ISDN number to identify the served user. If the served user includes an
ISDN number allocated to that access, or indicates that the deactivation of the CFNR supplementary
service shall apply to all ISDN numbers (if this functionality is offered by the service provider and
subscribed to by the served user) then the ISDN number, or the indication of all ISDN numbers, shall be
ignored. Deactivation of the CFNR supplementary service shall proceed as normal.
6.2.1.3 Registration
Registration of information is performed on activation of the CFNR supplementary service.
There are no separate registration procedures for the CFNR supplementary service.
6.2.2 Erasure
Not applicable.
6.2.3 Invocation and operation
The maximum number of diversions for each call shall be limited. The maximum number of diversions is a
service provider option with an upper limit of five diversions for each call. When counting the number of
diversions, all types of diversions shall be included.
6.2.3.1 Served user's view
If the CFNR supplementary service has been activated, then if the connection is not established within a
specified time interval after the served user has been informed of the call, then the service provider shall
attempt to forward the call.
The call shall be offered to the served user by means of basic call procedures.
According to the value of a subscription option, the served user shall be informed that the CFNR
supplementary service has been invoked on the call. This information shall be given when the network
originates the call to the forwarded-to user.

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When the CFNR supplementary service is invoked, the network shall set up a call to the forwarded-to
user. According to a network option, one of the following shall occur:
a) the call to the served user shall be retained until the network receives an indication that the
forwarded-to user is being informed of the call, or that the connection is established at the
forwarded-to user, whereupon the call shall be removed from the served user. If, on a multipoint
access, another terminal requests the establishment of the connection prior to the removal of the
call, then the connection shall be established and the forwarding ceased; or
b) the call shall be removed from the served user when the CFNR supplementary service is invoked.
6.2.3.2 Forwarded-to user's view
The forwarded-to user shall receive an indication that the CFNR supplementary service has been invoked
on the call. Depending on the value of one of the served user's subscription options the forwarded-to user
can also receive the ISDN number of the served user.
If multiple diversions have occurred, then the forwarded-to user can also be given the originally called
user's ISDN number provided that the presentation has been permitted by the diversion service invoked
for the originally called user. When multiple diversions occur the reason for forwarding given to the
forwarded-to user shall indicate the last type of forwarding (i.e. the invocation of the
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