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All drawings contained in this Recommendation have been done in Autocad.
Recommendation Q.730
ISDN SUPPLEMENTARY SERVICES
1 General
1.1 This Recommendation describes the signalling procedures for Supplementary
Services to be used in conjunction with the ISDN User Part defined in
Recommendations Q.761-764, Q.766 and the Transaction Capabilities Applications
Part (TCAP) defined in Recommendations Q.771-774.
Each Supplementary Service has been defined in separate sections each
containing the complete procedures encompassing both the ISDN User Part and the
procedures to be used on the top of TCAP where appropriate.
Each section contains a general paragraph giving details of the specific
service with references to the Stage I and II descriptions defined in the
relevant Recommendations of the I.200 and Q.80 Series. The call set-up procedures
and the actions taken at originating exchanges, etc. are defined. Arrow diagrams
showing the message flows for both successful and unsuccessful establishment of
the service are generally included. The formats and codings aspects are not
defined in this Recommendation but references are made to the appropriate ISDN
User Part, TC or SCCP Recommendations.
1.2 Information request/response
The "information request/response" message interchange described in the
calling line identity supplementary services uses a general request/response
mechanism (e.g. INR/INF messages) which can be used in the future for
supplementary services not currently defined (see Recommendation Q.764).
1.3 Exceeding the maximum message length (e.g. ISDN User Part 272 octets)
If for any reason the combination of basic plus supplementary service
information causes the overall maximum length of the message (e.g. Initial
Address Message) to be exceeded then the user-to-user supplementary service 1, if
included, should be rejected (see S 2 covering interactions).
The combination of other services which may cause the message length to be
exceeded will depend on the call state and the requested service.
1.4 Layout of Recommendation Q.730
S 1 General
S 2 User-to-user signalling (Note)
S 3 Close user group
S 4 Calling line identification (presentation and restriction)
S 5 Direct dialling in
S 6 Call forwarding (Note)
S 7 Time-out table for supplementary services (requires further study)
Note - The text for the explicit invocation of the user-to-user signalling
has been included as Annex A.
2 User-to-user signalling service
2.1 General description of user-to-user service
The user-to-user signalling supplementary service(s) provide(s) a means of
communication between two users by using the ISDN User Part or SCCP protocols
defined in Recommendations Q.711-714 and Q.761-764, 766. In order for the
services to be usable, they also have to be provided in the access protocol.
Fascicle VI.8 - Rec. Q.730 PAGE1
User-to-user signalling is used to exchange I.257 information between two
users to provide the user-to-user services described in Recommendation I.257.
This section is specific to Signalling System No. 7. The general description for
services 1-3 may be found in the last mentioned Recommendation and the functional
description in Recommendation Q.87.
2.1.1 User-to-user services
Three user-to-user signalling services associated with circuit-switched
calls that may be provided by the network users are:
Service 1: user-to-user signalling exchanged during the set-up and clearing
phases of a call, within ISDN User Part call set-up and release messages as
defined in Recommendation Q.763;
Service 2: user-to-user signalling exchanged during call set-up between the
address complete or call progress messages and the answer or connect
messages, within user-to-user information messages; and
Service 3: user-to-user signalling exchanged while a call is in the active
state, within user-to-user information messages.
All three services may be used separately or in any combination within a
single call. As an option at call set-up, users may be able to specify whether
the requested user-to-user signalling service(s) is(are) essential or
non-essential for the call (i.e. whether the call should be completed or not if
user-to-user information cannot be passed). Up to 128 octets of user information
may be transferred in a message in each of the three services1) . The 128 octets
does not include the user-to-user information parameter name, the protocol
control indicator or the length octets.
2.1.2 Service request
Service 1 may be requested implicitly by the presence of the user-to-user
information parameter in the Initial Address Message. An implicit request is
"non-essential" by default.
Explicit requests of Service 1 and 2 must be in the Initial Address
Message. Service 3 may be explicitly requested in the Initial Address Message
during call set-up. When there is an explicit request a single user-to-user
indicators parameter will be used with one of the following indications for each
of the three services:
- no information;
- requested, non-essential;
- requested, essential.
2.1.3 Response (Confirmation)
If explicit requests are used there should, in general, be explicit
responses in a user-to-user indicators parameter with one of the following
indications for each of the three services:
- no information;
- provided;
- not provided.
Implicit "not provided" responses occur when:
- Service 1 has been implicitly requested and no user-to-user information
is received in call set-up or release messages; or
- Service 1, 2 or 3 has been explicitly requested and there is no
indication of acceptance or rejection from call control.
2.1.4 Flow control
The exchange of user-to-user signalling is limited by flow control
procedures provided on the access by either the user or network. The need for
interexchange flow control procedures by the ISDN User Part for user-to-user
signalling should be evaluated.
2.2 Procedures for user-to-user signalling associated with circuit-switched
call
The following sections only specify the signalling procedure used to
implicitly invoke the Service 1. Signalling procedures defined to support the
other services are specified in Annex A.
2.2.1 User-to-user signalling, Service 1
2.2.1.1 General characteristics
Service 1 allows users to communicate with user-to-user signalling by
transferring user-to-user information within ISDN User Part messages during the
1) During an interim period of time, networks may support a lesser number (e.g. 32 octets)
due to protocol restrictions; 32 octets will always be supported. Restrictions may
apply to calls requesting user-to-user information more than 32 octets.
PAGE1 Fascicle VI.8 - Rec. Q.730
call set-up and clearing phases. The user-to-user signalling service provided is
not a guaranteed service. If for any reason the combination of the basic plus
supplementary service information causes the overall maximum length of the
message to be exceeded then if the User-to-user Signalling Service 1 is included,
then the service should be rejected.
2.2.1.2 User-to-user signalling in the call set-up phase - implicit service
request
Procedures for call set-up are as described in Recommendation Q.764, S 2,
with the following changes:
Service 1 may be invoked by sending the user-to-user information parameter
of variable length that is specified in Recommendation Q.763, S 3.34 in an
Initial Address Message that is requested in a call set-up request from call
control. This information parameter is transported across the network and
delivered unchanged to the terminating call control for the called user. The
user-to-user indicators parameter will not be sent.
The reception of a user-to-user information parameter in a call set-up or
release request from the terminating call control is an implicit indication of
the acceptance of Service 1.
The user or network may not be able to interpret incoming user-to-user
information. In such situations, the user should discard this information without
disrupting normal call handling. No specific signalling is provided by the
network to accommodate this situation.
2.2.1.3 Interworking
In the case of interworking with a non-ISDN network, the "interworking"
protocol control information will be returned to the originating exchange in the
first appropriate message, e.g. an Address Complete Message. Two ISDN networks
that interwork may have to retain knowledge of the service request until it is
clear whether both can support the service.
2.2.1.4 Rejection of implicit service requests
Networks that cannot provide the service requested may not return a
rejection indication.
2.2.1.5 User-to-user signalling in the call clearing phase
A user-to-user information parameter may be included in the Release
Message. The user-to-user information parameter received at the distant exchange
in the Release Message is passed to the call control for the remote user. In the
case of simultaneous clearing of the call, the Release Message may not reach the
distant local exchange and the user-to-user information will be lost.
2.2.1.6 Message flow diagrams
The message flow diagrams are shown in Figure 1/Q.730 as well as the use
of user-to-user signalling service 1 when implicitly requested in a
point-to-point configuration.
The messages shown with dashed lines are not part of the ISDN User Part
protocol and are for information only. For detailed information on the access
protocol user-to-user procedures the ISDN access protocol Recommendation should
be examined.
Figure 1/Q.730 - T1115880-88
2.2.2 Interaction with other supplementary services
2.2.2.1 Call forwarding services
Interactions with the call forwarding services are shown in the call
forwarding protocol sections.
2.2.2.2 Call waiting service
Interactions with the call waiting service are shown in the call waiting
protocol sections. (Call waiting is for further study.)
2.2.2.3 Other services
There are no known interactions with services other than those listed.
2.2.2.4 State transition diagrams
The state transition diagrams may be found in Stage 2 descriptions of the
user-to-user service.
3 Closed user group (CUG)
3.1 General
Fascicle VI.8 - Rec. Q.730 PAGE1
The closed user group (CUG) supplementary service enables a group of users
to intercommunicate only among themselves or, as required, one or more users may
be provided with incoming/outgoing access to users outside the group.
The stage I definition of the CUG service is given in Recommendation
I.255, and its stage II service definition including network functions are given
in Recommendation Q.85.
The realization of the CUG facilities is done by the provision of
interlock codes and is based on various validation checks as defined in Q.85 at
call set-up, determining whether or not a requested call to or from a user having
a CUG facility is allowed. In particular, a validation check is performed by
verifying that both the calling and called parties belong to the CUG indicated by
the interlock code.
The data for each CUG that a user belongs to can either be stored at the
local exchange to which the user is connected (decentralized administration of
CUG data), or at dedicated point(s) in the network (centralized administration of
CUG data).
In S 3.2 the call set-up procedure based on decentralized administration
of CUG data is specified making use of the ISDN User Part as defined in
Recommendations Q.761-764 and Q.766.
In S 3.3 the call set-up procedure based on centralized administration of
CUG data is specified making use of the ISDN User Part as defined in
Recommendations Q.761-764 and Q.766 and the Transaction Capabilities Application
Part (TCAP) as defined in Recommendations Q.771-775.
Section 3.4 specifies the application service element (ASE), situated
above the Transaction Capabilities Application Part (TCAP), and used for CUG
validation check with centralized administration of CUG data.
3.2 Call set-up procedure with decentralized administration of CUG
data
3.2.1 Originating exchange
The actions at the originating exchange at call set-up from a user
belonging to a CUG depend on the result of the validation checks performed there
based on whether the user belongs to one or more CUGs and on the combination of
CUG facilities that applies.
a) CUG call without outgoing access
If the result of the validation check indicates that the call should be
dealt with as a CUG call, the interlock code of the selected CUG is
obtained. The initial address message forwarded to the next exchange
then includes the interlock code together with an indication that the
call is a CUG call without outgoing access. The ISUP preference
indicator of the forward call indicators parameter in the IAM is set to
"ISUP required all the way".
b) CUG call with outgoing access
If the result of the validation check indicates that the call should be
dealt with as a CUG call with outgoing access, the interlock code of
the selected CUG together with an outgoing access indication is
obtained. The initial address message forwarded to the next exchange
then includes the interlock code together with an indication that the
call is a CUG call for which outgoing access is allowed. The ISUP
preference indicator of the forward call indicators parameter in the
IAM is set to "ISUP preferred all the way", unless another service
requires a more stringent setting.
PAGE1 Fascicle VI.8 - Rec. Q.730
c) Non-CUG call
If the result of the validation check indicates that the call should be
dealt with as a non-CUG call, the initial address message forwarded to
the next exchange then does not include an interlock code nor a CUG
call indication.
d) Call rejected
If the result of the validation check indicates that the call is to be
rejected, the call set-up is not initiated.
3.2.2 Transit exchange
With the possible exception of some gateway exchanges, each transit
exchange sets up a CUG call as an ordinary call. The information related to the
CUG facilities received from the preceding exchange, i.e. an interlock code, a
CUG call indication - possibly with an indication that outgoing access is allowed
- is forwarded to the succeeding exchange.
In the case of an international CUG call, no special functions are
required at the gateway exchange provided that the international interlock code
assigned to the international CUG concerned is used in the national network.
However, in the case where a national interlock code other than the applicable
international interlock code is used within a national network, interlock code
conversion is required at the gateway (or corresponding) exchange.
In case of interworking with a network which does not support the CUG
facility, the gateway exchange may release the call, depending on the contents of
the CUG call indicator in the received IAM. The action at the gateway exchange,
in this case, is indicated in Table 1/Q.730. In cases where a call is rejected as
the result of the interworking, a release message including the cause parameter
indicating ## 88 is sent towards the originating exchange.
3.2.3 Destination exchange
At the destination exchange a validation check of the acceptability of a
call is made according to the rule specified in the Recommendation Q.85 where
either the calling party (as indicated by a CUG call indication in the initial
address message received) or the called party belongs to a CUG. The call set-up
is continued only in cases where the information received checks with the
information stored at the destination exchange. Table 2/Q.730 indicates the
action to be taken by the destination exchange as the result of the validation
check.
In cases where a call is rejected as the result of the validation check
because of incompatible CUG information, a release message including the cause
parameter indicating one of the following values is sent towards the originating
exchange:
##55: Incoming calls barred within CUG
##87: Called user not member of CUG
##88: Incompatible destination
Figure 2/Q.730 illustrates example message flows for CUG calls with
decentralized administration of CUG data.
3.3 Call set-up procedure with centralized administration of CU
data
In the local exchange an indication is stored, showing only whether the
user has one or none of the closed user group facilities.
3.3.1 Originating exchange
The originating exchange requests the CUG validation check to the
dedicated point by invocation of the "CUG check 1" operation through TCAP. This
operation and associated parameters are described in S 3.4 of this
Recommendation. The following actions at the originating exchange depend on the
result of this validation check:
a) CUG call indication
If the result of the validation check for the calling user at the
originating exchange indicates that the check for the calling user has
been successful, the interlock code of the selected CUG possibly
together with an outgoing access indication is obtained. The initial
address message forwarded to the next exchange then includes the
interlock code together with an indication that the call is a CUG call
Fascicle VI.8 - Rec. Q.730 PAGE1
without outgoing access or a CUG call with outgoing access.
PAGE1 Fascicle VI.8 - Rec. Q.730
b) Non-CUG call indication
If the result of the validation check indicates that the call should be
dealt with as a non-CUG call, the initial address message forwarded to
the next exchange then does not include an interlock code nor a CUG
call indication.
c) Call rejected
If the result of the validation check indicates that the call is to be
rejected, the call set-up is not initiated.
3.3.2 Transit exchange
Refer to S 3.2.2.
3.3.3 Destination exchange
In the case of an incoming CUG call for which the validation check for the
calling user has successfully been performed, the received initial address
message includes the interlock code and CUG call indication possibly with an
indication that outgoing access is allowed. The destination exchange then
forwards the information received in the initial address message to the dedicated
point for CUG validation check. In this case, the destination exchange invokes
the "CUG check 2" operation through TCAP. This operation and associated
parameters are defined in S 3.4 of this Recommendation.
a) Check successful indication
If the result of the validation check indicates that the check has been
successful, the index of the CUG selected for the called user and
possibly an outgoing access indication are obtained. The CUG call
set-up request is forwarded to the called user with these indications.
b) Non-CUG call indication
If the result of the validation check indicates that the call should be
dealt with as a non-CUG call, the set-up request of a non-CUG call is
forwarded to the called user.
c) Call rejected
If the result of the validation check indicates that the call is
rejected, the reason why the call has been rejected is obtained. A
release message including the cause parameter indicating one of the
values as listed in S 3.2.3 is sent towards the originating exchange.
3.3.4 Dedicated point
At the dedicated point, the CUG validation check is performed according to
the rules defined in Recommendation Q.85. The procedures between the dedicated
point and the exchange follow those as defined in the ASE part of this
Recommendation.
Figure 3/Q.730 illustrates an example message flow for a CUG call with
centralized administration of CUG data.
TABLE 1/Q.730
Action at the gateway with a network without CUG capability
CUG call indicator in IAM Action at the gateway
exchange
CUG without outgoing Release the call with
access cause ##88
CUG with outgoing access Treat the call as an
ordinary call a)
Non-CUG Treat the call as an
ordinary call
a) Discard the interlock code parameter and change the CUG
call indicator of the optional forward call indicator to
indicate non-CUG call or discard the whole parameter if
appropriate.
TABLE 2/Q.730
Handling of a CUG call at the destination exchange
Class of called user
CUG call CUG match CUG CUG + IA No CUG
indicator in check
IAM
Fascicle VI.8 - Rec. Q.730 PAGE1
No ICB ICB No ICB ICB
CUG with OA Match CUG call Release CUG call Release
not allowed cause cause Release the
##55 ##55 call
No match Release the call Release the call with cause
with cause ##87 with cause ##87 ##88
CUG with OA Match CUG call Release CUG+OA Non-CUG
allowed cause call call Non-CUG
##55 call
No match Release the call Non-CUG call
with cause ##87
Non-CUG - Release the call
PAGE1 Fascicle VI.8 - Rec. Q.730
with cause ##88 Non-CUG call Non-CUG
call
IA Incoming access
OA Outgoing access
ICB Incoming calls barred
Match The interlock code in the received IAM matches one of the CUGs to which the called
user belongs.
No match The interlock code does not match any of the CUGs to which the called user
belongs.
Note - As OA attribute of the called user is of no concern at the destination exchange,
CUG+OA class is equivalent to CUG, and CUG/IA class is equivalent to CUG+IA in this table.
Subscription of preferential CUG by the called user is also of no concern in this table.
Fascicle VI.8 - Rec. Q.730 PAGE1
Figure 2/Q.730 - T1119340-88
Figure 3/Q.730 - T1119350-88
3.4 ASE for CUG service with centralized administration of CUG data
3.4.1 General
The application service element (ASE) for CUG service with centralized
administration of CUG data provides the procedures between the exchanges and the
CUG management centers (CMC) for CUG validation check.
Two similar but different procedures are defined for CUG validation check.
One is the procedure between the originating exchange of a CUG call and a CMC to
check the qualification of the calling user to establish the present CUG call.
The other is the procedure between the terminating exchange of a CUG call and a
CMC to check the qualification of the called user to accept the present CUG call.
One TCAP (Transaction Capabilities Application Part) operation is defined for
each of these procedures.
3.4.2 Procedures
To check the qualification of the calling user the originating exchange
initiates the transaction to the CMC by invocation of the CUG Check 1 operation
with appropriate parameters. The CMC, in response to this invocation, terminates
the transaction with the check result. The check result contains the interlock
code and other parameters in case of successful check or an error cause in case
of unsuccessful check. Figure 4/Q.730 shows the primitive flows between the ASE
and the TCAP at the exchange and between the ASE and the TCAP at the CMC for this
case. Table 3/Q.730 shows the result of the validation check which is performed
by the CMC, according to various parameters, concerning the calling user.
To check the qualification of the called user, the terminating exchange
initiates the transaction to the CMC by invocation of the CUG Check 2 operation
with appropriate parameters. The CMC, in response to this invocation, terminates
the transaction with the check result. The check result contains the index number
for the called user and other parameters in case of successful check or an error
cause in case of unsuccessful check. Figure 5/Q.730 shows the primitive flows
between the ASE and the TCAP at the exchange and between the ASE and the TCAP at
the CMC for this case. Table 4/Q.730 shows the result of the validation check
which is performed by the CMC, according to various parameters, concerning the
called user.
3.4.3. Operations
3.4.3.1 Description of operations
3.4.3.1.1 CUG Check 1
This operation is used between the originating exchange of a call and a
dedicated point for CUG validation check of the calling user.
3.4.3.1.2 CUG Check 2
This operation is used between the terminating exchange of a call and a
dedicated point for CUG validation check of the called user.
TABLE 3/Q.730
Validation check of CUG call concerning the calling user
Indication from
calling user
Calling user CUG call with CUG + OA call CUG + OA call Non-CUG call
class index with index without index
CUG with CUG call a) c) CUG call a) c) CUG call a) CUG call
pref. IC: specified IC: specified IC: preferential IC: preferential
CUG CUG CUG CUG
CUG without CUG call a) c) CUG call a) c) Return Error Return Error
pref. IC: specified IC: specified cause ##62 cause ##62
CUG CUG
CUG + OAI CUG + OA a) c) CUG + OA a) c) CUG + OA a)
with pref. IC: specified IC: specified
CUG CUG
PAGE1 Fascicle VI.8 - Rec. Q.730
IC: preferential CUG + OA b)
CUG IC: preferential
CUG
CUG + OAI CUG + OA a) c) CUG + OA b) c) Non-CUG call Non-CUG call
without pref. IC: specified IC: specified
CUG CUG
CUG + OAE CUG call a) c) CUG + OA b) c) CUG + OA b) CUG call b)
with pref. IC: specified IC: specified IC: preferential IC: preferential
CUG CUG CUG CUG
CUG + OAE CUG call a) c) CUG + OA b) c) Non-CUG call Return Error
without pref. IC: specified IC: specified cause ##62
CUG CUG
No CUG Return Error Return Error Return Error Non-CUG call
cause ##50 cause ##50 cause ##50
OAE Outgoing access, explicit request required
OAI Outgoing access, implicit outgoing access for all calls
IC Interlock code of the CUG selected
Note - As IA (incoming access) attribute of the calling user is of no concern for this
validation check, CUG + IA class is equivalent to CUG, and CUG + OA/IA class is equivalent
to CUG + OA in this table.
a) In case of OCB (outgoing calls barred) within the CUG, Return Error with cause
##53.
b) In case of OCB within the CUG, the call is interpreted as a non-CUG call.
c) In the case where the specified index does not match any of the registered
indices, Return Error with cause ##90.
Fascicle VI.8 - Rec. Q.730 PAGE1
TABLE 4/Q.730
Validation check of CUG call concerning the called user
Class of called user
CUG call CUG match CUG CUG + IA
indication in check
IAM
No ICB ICB No ICB ICB No CUG
CUG with OA Match CUG call Return CUG call Return
not allowed Error Error
cause cause Return
##55 ##55 Error cause
##88
No match Return Error cause Return Error cause
##87 ##87
CUG with OA Match CUG call
allowed
PAGE1 Fascicle VI.8 - Rec. Q.730
Return CUG + OA Non-CUG
Error call call
cause Non-CUG
##55 call
No match Return Error cause Non-CUG call
##87
Non-CUG - Return Error cause Non-CUG call Non-CUG
##87 call
IA Incoming access
OA Outgoing access
ICB Incoming calls barred
Match The interlock code in the received IAM matches one of the CUGs to which the called
user belongs.
No match The interlock code does not match any of the CUGs to which called user belongs.
Note - OA attribute of the called user is of no concern at the destination exchange, the
CUG + OA class is equivalent to CUG, and CUG + OA/IA class is equivalent to CUG + IA in
this table. Subscription of preferential CUG by the called user is also of no concern in
this table.
Fascicle VI.8 - Rec. Q.730 PAGE1
Figure 4/Q.730 - T1119360-88
Figure 5/Q.730 - T1119370-88
3.4.3.2 Parameters of operations and outcomes
3.4.3.2.1 CUG Check 1
CUG Check 1 Timer = x seconds Class = 1 Code = 00000001
Parameters with Invoke Optional/ Reference
Mandatory (S)
CallingUserIndex O 3.4.3.3.1
CUGCallIndicator M 3.4.3.3.2
CallingPartyNumber M 3.4.3.3.3.
Parameters with Return Result
CUGInterlockCode M 3.4.3.3.5
CUGCallIndicator M 3.4.3.3.2
Linked Operations
PAGE1 Fascicle VI.8 - Rec. Q.730
Not applicable
Errors
UnsuccessfulCheck 3.4.3.3.7
CUGCheck1 OPERATION
PARAMETER SEQUENCE { CallingUserIndex OPTIONAL, CUGCallIndicator,
{ CallingPartyNumber }
RESULT SEQUENCE { CUGInterlockCode CUGCallIndicator }
ERRORS { UnsuccessfulCheck }
::= 1
Fascicle VI.8 - Rec. Q.730 PAGE1
3.4.3.2.2 CUG Check 2
CUG Check 2 Timer = x seconds Class = 1 Code = 00000010
Parameters with Invoke Optional/ Reference
Mandatory (S)
CUGInterlockCode M 3.4.3.3.5
CUGCallIndicator M 3.4.3.3.2
CalledPartyNumber M 3.4.3.3.4
Parameters with Return Result
CalledUserIndex O 3.4.3.3.6
CUGCallIndicator M 3.4.3.3.2
Linked Operations
Not applicable
Errors
UnsuccessfulCheck 3.4.3.3.7
CUGCheck2 OPERATION
PARAMETER SEQUENCE { CUGInterlockCode, CUGCallIndicator,
{ CalledPartyNumber }
RESULT SEQUENCE { CalledUserIndex OPTIONAL, CUGCallIndicator }
ERRORS { UnsuccessfulCheck }
::= 2
3.4.3.3 Parameter coding
3.4.3.3.1 The CallingUserIndex is the local index at the calling user to identify
a particular CUG he belongs to.
CallingUserIndex Code = 10000001
PAGE1 Fascicle VI.8 - Rec. Q.730
Contents Meaning
IA5 Character String One IA5 character represents one digit of the
CUG index value
CallingUserIndex ::= [1] IMPLICIT LocalIndex
LocalIndex ::= IA5 STRING
- - The maximum number of digits is four.
Fascicle VI.8 - Rec. Q.730 PAGE1
3.4.3.3.2 The CUGCallIndicator indicates whether the call is requested or
designated as a CUG call and whether outgoing access is requested or allowed.
CUGCallIndicator Code = 10000010
Contents Meaning
00000000 Non-CUG call
00000001 Non-CUG call
00000010 CUG call with outgoing access
00000011 CUG call without outgoing access
CUGCallIndicator ::= [2] IMPLICIT CallIndicator
CallIndicator ::= INTEGER {
NonCUGCall (0),
NonCUGCall(1),
outgoingAccessAllowedCUGCall (2),
outgoingAccessNotAllowedCUGCall (3) },
3.4.3.3.3 The CallingPartyNumber is the network (e.g. E.164) number of the
calling party. It is expressed in the same manner as the ISUP Calling party
number in S 3.8 of Recommendation Q.763. The code of this parameter is
"10000011".
3.4.3.3.4 The CalledPartyNumber is the network (e.g. E.164) number of the called
party. It is expressed in the same manner as the ISUP Called party number in S
3.7 of Recommendation Q.763. The code of this parameter is "10000100".
3.4.3.3.5 The CUGInterlockCode is the code to uniquely identify a CUG inside the
network. It is expresed in the same manner as the ISUP CUG interlock code in S
3.13 of Recommendation Q.763. The code of this parameter is "10000101".
3.4.3.3.6 The CalledUserIndex is the local index at the called user to identify a
particular CUG he belongs to. Refer to S 3.4.3.3.1. The code of this parameter is
"10000110".
3.4.3.3.7 Errors
UnsuccessfulCheck Code = 00000001
Parameters
Cause 3.4.3.3.8
UnsuccessfulCheck Error
PARAMETERS { Cause }
::= 1
PAGE1 Fascicle VI.8 - Rec. Q.730
3.4.3.3.8 The Cause indicates the reason why the CUG check is unsuccessful.
Cause Code = 10000111
Contents binary (decimal) Meaning
00110010 (50) Requested facility not subscribed
00110101 (53) Outgoing calls barred within CUG
00110111 (55) Incoming calls barred within CUG
00111110 (62) InconsistencyInDesignatedOutgoingAccessInformationAnd
SubscriberClass
01011010 (90) Non-existent CUG
01010111 (87) Called user not member of CUG
01011000 (88) Incompatible destination
01101110 (110) Inconsistency in data
Cause ::= [7] IMPLICIT CauseCode
CauseCode ::= INTEGER {
requestedFacilityNotSubscribed(50),
outgoingCallsBarredWithinCUG(53),
incomingCallsBarredWithinCUG(55),
inconsistencyInDesignatedOutgoingAccessInformationAnd
SubscriberClass(62),
nonExistentCUG(90),
calledUserNotMemberofCUG(87),
incompatibleDestination(88),
inconsistencyInData(110) }
R
Restriction service
Calling Line Identification Presentation (CLIP) is a supplementary service
offered to the called party which provides the calling party's ISDN number,
possibly with additional address information (i.e. subVaddress), to the called
party.
Calling Line Identification Restriction (CLIR) is a supplementary service
offered to the calling party to restrict presentation of the calling party's ISDN
number, possibly with additional address information (i.e. sub-address), to the
called party.
The stage 1 definitions for the CLIP and CLIR services are given in the
Recommendation I.254 and the stage 2 service definitions including network
functions, are given in Recommendation Q.84. This stage 3 description of CLIP and
CLIR use the ISDN User Part protocol as defined in Recommendations Q.761V764 and
Q.766.
4.1 Description of the Calling Line Identity Presentation (CLIP) service
Calling Line Identity Presentation (CLIP) is a user facility that enables
a user to be informed on incoming calls, of the address of the calling party.
When provided the facility applies to all incoming calls except for when the
calling party has the Calling Line Identity Restriction (CLIR) facility active
[see ' 4.2 below] or the complete number of the calling party is not available at
the destination exchange.
The Calling Line Identity (CLI) is generally the ISDN number of the
calling party (with possible additional address information, i.e. subVaddress)
which may be provided by the network or partly by the calling party.
Fascicle VI.8 - Rec. Q.730 PAGE1
In the case where a national network does not always provide the CLIP
facility, the included CLI may be the known part of the ISDN number at the
interworking point (e.g. Trunk Code).
In the case where a calling party is an ISPBX, the network may send the
ISDN number of the PABX attendant operator or, if provided by the calling party,
the DDI number of the extension as the CLI.
When the CLI is provided by the user or ISPBX it is verified or screened
for validity by the network, i.e. the CLI provided by the user is within the
known number range for that user.
i) If the user provided CLI is valid the Calling Number Parameter field
contains the CLI in the Address Signal with the Screening indicator set
to "user provided verified and passed".
ii) If the user provided CLI is not valid or screened the originating
exchange defaults to the network provided CLI for the Address Signals
of the Calling Party Number parameter field with the Screening
indicator set to "network provided".
When the CLI is provided by the network the originating exchange includes
the stored CLI set against the calling party and sets the screening indicator to
"network provided".
The CLI sent to the called user should contain all the necessary digits to
enable a call to be established in the reverse direction.
Note - This may not always be possible if, for example, the DDI extension
of an ISPBX is not provided by the calling party.
Information indicating that a subscriber has the user access to the CLIP
facility is available in the exchange to which the subscriber is connected.
4.1.1 Call set-up procedure
The call control procedure and the information included in Call Control
Messages vary depending on whether the CLI is included in the Initial Address
Message and also whether the calling party has indicated a request to use the
CLIR facility for this call.
Two different call control procedures can be used to provide the CLIP
facility. Both procedures are specified for international use, however, the first
method is to be preferred.
4.1.1.1 The Calling Line Identity is included in the Initial Address Message
When the CLI is available for insertion in the IAM the systematic
inclusion of this parameter, in the IAM, is recommended. However, it is realized
that under certain interworking conditions the CLI may only be available
subsequent to the transmission of the IAM.
In this situation, to avoid unnecessary unsuccessful requests for the CLI,
the following procedures are recommended:
a) If the CLI cannot be included in the IAM (for any reason) but is
available and may be requested with a good chance of receiving it, then
the optional field "calling party number parameter" should not be
included in the IAM.
b) If the CLI cannot be transferred (because it is not allowed to be
passed or because the national network cannot provide the number), then
the optional field "calling party number parameter" should be included
in the IAM with the indication "presentation restricted" or "address
not available" set as appropriate in the Address Presentation
Restricted indicator.
The CLI is sent to the called party in accordance with the user-network
interface protocol.
For calls between networks (e.g. an outgoing ISC as referred to in b)
above) the outgoing gateway exchange may remove any CLI digits from the IAM and
indicate in the calling party number parameter that presentation is restricted.
Interworking exchanges may generate only part of the CLI for inclusion in
the IAM (e.g. trunk code). This will be indicated in the number incomplete
indicator in the Calling Party Number Parameter field.
In the case where the destination exchange receives only part of the CLI,
(it is assumed to be the most significant part), the CLI is forwarded to the
called party with the appropriate indications set.
PAGE1 Fascicle VI.8 - Rec. Q.730
4.1.1.2 The Calling Line Identity is not included in the Initial Address
Message
In the case where the CLIP facility is applied, and the IAM has indicated
that the CLI may be available, an Information Request Message is sent towards the
originating exchange with the Information Request Indicator Parameter field bit
set to the calling party address requested.
When receiving the request for Calling Party Address and the CLI is
available, the originating/interworking exchange sends an information message
containing the Calling Party Number Parameter field with the appropriate
indications and CLI included.
In the case where the identity of the calling party is not available or is
not allowed to be forwarded outside the network, the response will be an
Information message including the Information Indicators Parameter Field
indicating the CLI is not available.
In the case where the destination exchange receives only part of the CLI,
(it is assumed to be the most significant part), the CLI is forwarded to the
called party with the appropriate indications set.
The CLI is sent to the called party in accordance with the user-network
interface protocol.
In the case where the destination exchange receives the "presentation
restricted" or an "address not available", in the Presentation Restriction
indicator of the Information message, the calling party address is not forwarded
to the called party.
4.1.1.3 Message Sequence diagrams for CLIP
Figures 6/Q.730 and 7/Q.730 describe the message flows for CLIP.
Figure 6/Q.730 - T1121490-89
Fascicle VI.8 - Rec. Q.730 PAGE1
Figure 7/Q.730 - T1121500-89
4.2 Description of the Calling Line Identity Restriction (CLIR) service
Calling Line Identification Restriction (CLIR) is a user facility offered
to restrict the presentation of the Calling Line Identity to the Called Party.
The Calling Line Identity (CLI) is the ISDN number of the calling party
possibly with additional address information.
Information that a subscriber has the Calling Line Identity Restriction
facility is available at the exchange to which the subscriber is connected.
4.2.1 Normal Case
When CLIR is applicable the originating exchange will provide the
destination node with a notification that the Calling Line Identity is not
allowed to be presented at the called party. In this case the Calling Line
Identity will be marked as presentation restricted, in the Address Presentation
Restricted Indicator, when it is passed across the network, in either an Initial
Address Message or Information Message. In the case of CLIR the Calling Line
Identity will not be included in the call offering to the called party's
installation.
4.2.2 Abnormal Case
4.2.2.1 Override Category within an ISDN
As a national option the terminating exchange can override the
presentation restriction indication and the CLI presented at the called
subscriber for specific called party's categories (e.g. Police).
PAGE1 Fascicle VI.8 - Rec. Q.730