S tandard ECMA-263
3rd Edition - December 2001
Standardizing Information
and
Communication
Systems
Private Integrated Services Network (PISN) Specification, Functional Model and Information Flows Call Priority Interruption and Call Priority Interruption Protection Supplementary Services
Phone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http://www.ecma.ch - Internet: [email protected]
.
S tandard ECMA-263
3rd Edition - December 2001
Standardizing
Information
and
Communication
Systems
Private Integrated Services Network (PISN) Specification, Functional Model and Information Flows Call Priority Interruption and Call Priority Interruption Protection Supplementary Services (CPI(P)SD)
Phone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http://www.ecma.ch - Internet: [email protected] IW
Ecma-263.doc
31-01-02 15,55
.
Brief History
This Standard is one of a series of ECMA Standards defining services and signalling protocols applicable to Private Integrated Services Networks (PISNs). The series uses ISDN concepts as developed by ITU-T and conforms to the framework of International Standards for Open Systems Interconnection as defined by ISO/IEC. This particular Standard specifies the Call Priority Interruption (CPI) and Call Priority Interruption Protection (CPIP) supplementary services. This Standard is based upon the practical experience of ECMA member companies and the results of their active and continuous participation in the work of ISO/IEC JTC1, ITU-T, ETSI and other international and national standardization bodies. It represents a pragmatic and widely based consensus. There are currently no equivalent services specified by ITU-T or ETSI for public ISDN. Compared to the 1st Edition of Standard ECMA-263 (published by ECMA in September 1997), the 2nd Edition (published by ECMA in September 1998) incorporated changes to achieve complete alignment with International Standard ISO/IEC 15991:1998(E) published by ISO/IEC in December 1998.
Adopted as 3rd Edition of Standard ECMA-263 by the General Assembly of December 2001.
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Table of contents 1
Scope
1
2
Conformance
1
3
References (normative)
1
Definitions E x te r n a l d e f in itio n s A d d itio n a l n e tw o r k f e a tu r e Call, Basic call Call Priority Interruption Capability Level (CPICL) C a l l P r i o r i t y I n t e r r u p t i o n P r o te c t i o n L e v e l ( C P I P L ) Established call I mp e n d in g p r io r ity in te r r u p tio n s ta te I mp e n d in g p r io r ity in te r r u p tio n w a r n in g n o tif ic a tio n Non-priority call Priority call Protected call Served user T i me t o p r i o r i t y i n t e r r u p t i o n Unprotected call
2 2 2 2 2 3 3 3 3 3 3 3 3 3 3
List of acronyms
3
4 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10 4.11 4.12 4.13 4.14 5 6
S S - C P I s t a g e 1 s p e c if ic a t io n 6 . 1 D e s c r ip tio n 6.1.1 G e n e r a l d e s c r ip tio n 6.1.2 Q u a l i f i c a t i o n s o n a p p l i c a b i l i t y t o t e l e c o mmu n ic a t i o n s e r v i c e s 6.2 Procedure 6.2.1 P r o v is io n /w ith d r a w a l 6.2.2 N o r ma l p r o c e d u r e s 6.2.3 E x c e p tio n a l p r o c e d u r e s 6 . 3 I n te r a c tio n w ith o th e r s u p p le me n ta r y s e r v ic e s a n d A N F s 6.3.1 C a l l i n g N a me I d e n t i f i c a t i o n P r e s e n t a t i o n ( S S - C N I P ) 6.3.2 C o n n e c t e d N a me I d e n t i f i c a t io n P r e s e n ta tio n ( S S - CO N P ) 6.3.3 C o mp l e t i o n o f C a l l t o B u s y S u b s c r i b e r ( S S - C C B S ) 6.3.4 C o mp l e t i o n o f C a l l o n N o R e p ly ( S S - C C N R ) 6.3.5 Call Transfer (SS-CT) 6.3.6 Ca ll F o r w a r d in g U n c o n d itio n a l ( S S - CF U ) 6.3.7 C a l l F o r w a r d in g B u s y ( S S - C F B ) 6.3.8 Ca ll F o r w a r d in g N o Re p ly ( S S - CF N R) 6.3.9 Call Deflection (SS-CD) 6.3.10 P a t h R e p l a c e me n t ( A N F - P R )
4 4 4 4 4 4 4 6 6 6 6 6 6 6 6 7 7 7 7
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7
6.3.11 Call Offer (SS-CO) 6.3.12 Call Intrusion (SS-CI) 6.3.13 Do not Disturb (SS-DND) 6.3.14 Do not Disturb Override (SS-DNDO) 6.3.15 A d v ic e o f Ch a r g e ( S S - A O C) 6.3.16 Recall (SS-RE) 6.3.17 Call Interception (ANF-CINT) 6.3.18 T r a n s it Co u n te r ( A N F - T C) 6.3.19 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l L o c a t i o n R e g is t r a t i o n ( S S - W T L R ) 6.3.20 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l I n c o min g C a l l ( A N F - W T MI ) 6.3.21 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l O u t g o in g C a l l ( A N F - W T M O ) 6.3.22 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l A u t h e n t i c a t i o n o f a W T M u s e r ( S S - W T A T ) 6.3.23 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l A u t h e n t i c a t i o n o f a P I S N ( S S - W T A N ) 6.3.24 Me s s a g e W a itin g I n d ic a tio n ( S S - MW I ) 6.3.25 C o mmo n I n f o r ma t i o n ( A N F - C MN ) 6.3.26 C a l l P r i o r i t y I n t e r r u p t i o n P r o te c t i o n ( S S - C P I P ) 6 . 4 I n te r w o r k in g c o n s id e r a tio n s 6.5 Overall SDL
7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 8 8 8
S S - C P I P s t a g e 1 s p e c if ic a t io n 7 . 1 D e s c r ip tio n 7.1.1 G e n e r a l d e s c r ip tio n 7.1.2 Q u a l i f i c a t i o n s o n a p p l i c a b i l i t y t o t e l e c o mmu n ic a t i o n s e r v i c e s 7.2 Procedure 7.2.1 P r o v is io n /w ith d r a w a l 7.2.2 N o r ma l p r o c e d u r e s 7.2.3 E x c e p tio n a l p r o c e d u r e s 7 . 3 I n te r a c tio n w ith o th e r s u p p le me n ta r y s e r v ic e s a n d A N F s 7.3.1 C a l l i n g N a me I d e n t i f i c a t i o n P r e s e n t a t i o n ( S S - C N I P ) 7.3.2 C o n n e c t e d N a me I d e n t i f i c a t io n P r e s e n ta tio n ( S S - CO N P ) 7.3.3 C o mp l e t i o n o f C a l l t o B u s y S u b s c r i b e r ( S S - C C B S ) 7.3.4 Co mp le tio n o f Ca ll o n N o Re p ly ( S S - CCN R) 7.3.5 Call Transfer (SS-CT) 7.3.6 Ca ll F o r w a r d in g U n c o n d itio n a l ( S S - CF U ) 7.3.7 C a l l F o r w a r d in g B u s y ( S S - C F B ) 7.3.8 Ca ll F o r w a r d in g N o Re p ly ( S S - CF N R) 7.3.9 Call Deflection (SS-CD) 7.3.10 P a t h R e p l a c e me n t ( A N F - P R ) 7.3.11 Call Offer (SS-CO) 7.3.12 Ca ll I n tr u s io n ( S S - CI ) 7.3.13 Do not Disturb (SS-DND) 7.3.14 Do not Disturb Override (SS-DNDO) 7.3.15 A d v ic e o f Ch a r g e ( S S - A O C) 7.3.16 Recall (SS-RE) 7.3.17 Call Interception (ANF-CINT) 7.3.18 T r a n s it Co u n te r ( A N F - T C)
12 12 12 12 12 12 12 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 14 14 14 14
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7.3.19 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l L o c a t i o n R e g is t r a t i o n ( S S - W T L R ) 7.3.20 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l I n c o min g C a l l ( A N F - W T MI ) 7.3.21 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l O u t g o in g C a l l ( A N F - W T M O ) 7.3.22 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l A u t h e n t i c a t i o n o f a W T M u s e r ( S S - W T A T ) 7.3.23 I n t e r a c t i o n w i t h W ir e l e s s T e r mi n a l A u t h e n t i c a t i o n o f a P I S N ( S S - W T A N ) 7.3.24 Me s s a g e W a itin g I n d ic a tio n ( S S - MW I ) 7.3.25 C o mmo n I n f o r ma t i o n ( A N F - C MN ) 7.3.26 Call Priority Interruption (SS-CPI) 7 . 4 I n te r w o r k in g c o n s id e r a tio n s 7.5 Overall SDL
14 14 14 14 14 14 14 14 14 14
8
S S - C P I s t a g e 2 s p e c if ic a t io n 8 . 1 F u n c tio n a l mo d e l 8.1.1 F u n c tio n a l mo d e l d e s c r ip tio n 8.1.2 Description of Functional Entities 8.1.3 Re la tio n s h ip o f f u n c tio n a l mo d e l to b a s ic c a ll f u n c tio n a l mo d e l 8 . 2 I n f o r ma t i o n f l o w s 8.2.1 D e f in itio n o f in f o r ma tio n f lo w s 8.2.2 Re la tio n s h ip o f in f o r ma tio n f lo w s to b a s ic c a ll in f o r ma tio n f lo w s 8.2.3 I n f o r ma tio n f lo w s e q u e n c e s 8.3 Functional Entity actions 8.3.1 A c tio n s o f F E 1 8.3.2 A c tio n s o f F E 2 8.3.3 A c tio n s o f F E 3 8.3.4 A c tio n s o f F E 4 8.3.5 A c tio n s o f F E 5 8 . 4 F u n c t i o n a l e n t i t y b e h a v io u r 8.4.1 Be h a v io u r o f F E 1 8.4.2 Be h a v io u r o f F E 2 8.4.3 Be h a v io u r o f F E 3 8.4.4 Be h a v io u r o f F E 4 8.4.5 Be h a v io u r o f F E 5 8 . 5 A l l o c a t i o n o f F u n c t i o n a l E n t i t i e s t o p h ys i c a l e q u ip me n t 8 . 6 I n te r w o r k in g c o n s id e r a tio n s
16 16 16 16 17 17 17 19 19 23 23 23 23 23 24 24 24 26 27 29 30 31 31
9
S S - C P I P s t a g e 2 s p e c if ic a t io n 9 . 1 F u n c tio n a l mo d e l 9.1.1 F u n c tio n a l mo d e l d e s c r ip tio n 9.1.2 Description of Functional Entities 9.1.3 Re la tio n s h ip o f f u n c tio n a l mo d e l to b a s ic c a ll f u n c tio n a l mo d e l 9 . 2 I n f o r ma t i o n f l o w s 9.2.1 D e f in itio n o f in f o r ma tio n f lo w s 9.2.2 Re la tio n s h ip o f in f o r ma tio n f lo w s to b a s ic c a ll in f o r ma tio n f lo w s 9.2.3 I n f o r ma tio n f lo w s e q u e n c e s 9.3 Functional Entity actions 9.3.1 A c tio n s o f F E 1
31 31 31 32 32 33 33 34 34 37 37
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9.3.2 A c tio n s o f F E 2 9.3.3 A c tio n s o f F E 3 9.3.4 A c tio n s o f F E 4 9.3.5 A c tio n s o f F E 5 9 . 4 F u n c t i o n a l e n t i t y b e h a v io u r 9.4.1 Be h a v io u r o f F E 1 9.4.2 Be h a v io u r o f F E 2 9.4.3 Be h a v io u r o f F E 3 9.4.4 Be h a v io u r o f F E 4 9.4.5 Be h a v io u r o f F E 5 9 . 5 A l l o c a t i o n o f F u n c t i o n a l E n t i t i e s t o p h ys i c a l e q u ip me n t 9 . 6 I n te r w o r k in g c o n s id e r a tio n s
37 37 38 38 38 39 40 41 42 43 44 44
1
Scope This Standard specifies the Supplementary Services Call Priority Interruption (SS-CPI) and Call Priority Interruption Protection (SS-CPIP), which are applicable to various basic services supported by Private Integrated Services Networks (PISN). Basic services are specified in ECMA-142. NOTE 1 This edition of this Standard does not apply to the circuit-mode Multiple Rate Bearer Service. SS-CPI is a supplementary service that allows a call request for a priority call to proceed successfully in the case that there is no user information channel available. This is accomplished by force releasing an established call of lower priority. SS-CPIP is a supplementary service that allows for the protection of calls against interruption from other, priority, calls. SS-CPI and SS-CPIP are described separately because SS-CPI is a service used by a calling user, and SSCPIP is a service used by either a calling user or a called user. Supplementary service specifications are produced in three stages, according to the method described in ETS 300 387. This Standard contains the stage 1 and stage 2 specifications of SS-CPI. The stage 1 specification (clause 6) specifies the general feature principles and capabilities. The stage 2 specification (clause 7) identifies the Functional Entities involved in the supplementary service and the information flows between them.
2
Conformance In order to conform to this Standard, a stage 3 standard shall specify signalling protocols and equipment behaviour that are capable of being used in a PISN which supports the supplementary service specified in this Standard. This means that, to claim conformance, a stage 3 standard is required to be adequate for the support of those aspects of clause 6 (stage 1) and clause 7 (stage 2) which are relevant to the interface or equipment to which the stage 3 standard applies.
3
References (normative) The following standards contain provisions which, through reference in this text, constitute provisions of this Standard. All standards are subject to revision, and parties to agreements based on this Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. In the case of references to ECMA standards that are aligned with ISO/IEC International Standards, the number of the appropriate ISO/IEC International Standard is given in brackets after the ECMA reference. ECMA-133
Private Integrated Services Network (PISN) - Reference Configuration for PISN Exchanges (PINX) (International Standard ISO/IEC 11579-1)
ECMA-142
Private Integrated Services Network (PISN) - Circuit-mode 64 kbit/s Bearer Services Service Description, Functional Capabilities and Information Flows (International Standard ISO/IEC 11574)
ECMA-173
Private Integrated Services Network (PISN) - Specification, Functional Model and Information Flows - Call Diversion Supplementary Services (International Standard ISO/IEC 13872)
ECMA-175
Private Integrated Services Network (PISN) - Specification, Functional Model and Information Flows - Path Replacement Additional Network Feature (International Standard ISO/IEC 13863)
ECMA-177
Private Integrated Services Network (PISN) - Specification, Functional Model and Information Flows - Call Transfer Supplementary Service (International Standard ISO/IEC 13865)
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ECMA-185
Private Integrated Services Network (PISN) - Specification, Functional Model and Information Flows - Call Completion Supplementary Services (International Standard ISO/IEC 13866)
ECMA-220
Private Integrated Services Network (PISN) - Specification, Functional Model and Information Flows - Call Interception Additional Network Feature (International Standard ISO/IEC 15053)
ETS 300 387
Private Telecommunication Network (PTN); Method for the specification of basic and supplementary services (1994)
ITU-T Rec. I.112
Vocabulary of terms for ISDNs (1993)
ITU-T Rec. I.210
Principles of telecommunication services supported by an ISDN and the means to describe them (1993)
ITU-T Rec. Z.100 Specification and description language (1999)
4
Definitions For the purposes of this Standard, the following definitions apply.
4.1
External definitions This Standard uses the following terms defined in other documents: − Basic service
(ITU-T Rec. I.210)
− Private Integrated Services Network (PISN)
(ECMA-133)
− Private Integrated services Network eXchange (PINX)
(ECMA-133)
− Service
(ITU-T Rec. I.112)
− Signalling
(ITU-T Rec. I.112)
− Supplementary Service
(ITU-T Rec. I.210)
− User
(ECMA-142)
This Standard refers to the following basic call Functional Entities (FE) defined in ECMA-142: − Call Control (CC) − Call Control Agent (CCA) This Standard refers to the following basic call inter-FE relationships defined in ECMA-142: − r1 − r2 − r3 This Standard refers to the following basic call information flows defined in ECMA-142: − DISCONNECT request/indication − RELEASE request/indication − SETUP request/indication
4.2
Additional network feature A capability, over and above that of a basic service, provided by a PISN, but not directly to a PISN user.
4.3
Call, Basic call An instance of the use of a basic service.
4.4
Call Priority Interruption Capability Level (CPICL) A parameter indicating the priority of a call.
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4.5
Call Priority Interruption Protection Level (CPIPL) A parameter indicating a level of protection of a call against interruption from other calls.
4.6
Established call The active call that is selected for interruption.
4.7
Impending priority interruption state The condition of an established call and a priority call after provision of an Impending priority interruption warning notification and before the release of the established call.
4.8
Impending priority interruption warning notification A notification provided before the release of the established call.
4.9
Non-priority call A call that has not been assigned a CPICL value.
4.10
Priority call A call that has a CPICL value greater than zero. NOTE 2 A priority call may also be a protected call.
4.11
Protected call A call that has a CPIPL value greater than zero. NOTE 3 A protected call may also be a priority call.
4.12
Served user The user who requests SS-CPI and/or SS-CPIP.
4.13
Time to priority interruption The duration of the impending priority interruption state.
4.14
Unprotected call A call which has not been assigned a CPIPL value or has a CPIPL value equal to zero.
5
List of acronyms ANF AOC CC CCA CCBS CCNR CD CFB CFNR CFU CI CICL CINT CLIP CLIR CMN CNIP CNIR CO COLP
Additional Network Feature Advice Of Charge Call Control (Functional Entity) Call Control Agent (Functional Entity) Call Completion to Busy Subscriber Call Completion on No Reply Call Deflection Call Forwarding Busy Call Forwarding No Reply Call Forwarding Unconditional Call Intrusion Call Intrusion Capability Level Call INTerception Calling Line Identification Presentation Calling/Connected Line Identification Restriction CoMmoN Information Calling Name Identification Presentation Calling/Connected Name Identification Restriction Call Offer Connected Line Identification Presentation
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CONP CPI CPICL CPIP CPIPL CT DND DNDO FE ISDN MWI PINX PISN PR RE SDL SS TC TE WTAU WTLR WTMI WTMO
6
Connected Name Identification Presentation Call Priority Interruption Call Priority Interruption Capability Level Call Priority Interruption Protection Call Priority Interruption Protection Level Call Transfer Do Not Disturb Do Not Disturb Override Functional Entity Integrated Services Digital Network Message Waiting Indication Private Integrated services Network eXchange Private Integrated Services Network Path Replacement REcall Specification and Description Language Supplementary Service Transit Counter Terminal Equipment Wireless Terminal AUthentication Wireless Terminal Location Registration Wireless Terminal Mobility Incoming call Wireless Terminal Mobility Outgoing call
SS-CPI stage 1 specification
6.1 6.1.1
Description General description Call Priority Interruption (SS-CPI) is a supplementary service that allows a call request for a priority call to proceed successfully in the case that there is no user information channel available. A priority interruption only occurs if the served user has a higher Call Priority Interruption Capability Level (CPICL) than the Call Priority Interruption Protection Level (CPIPL) of at least one of the active calls on the selected route.
6.1.2
6.2 6.2.1
Qualifications on applicability to telecommunication services SS-CPI is applicable to all basic services defined in ECMA-142.
Procedure P r o v is io n /wit h d r a wa l SS-CPI shall be provided or withdrawn after pre-arrangement with the service provider. SS-CPI shall be provided on a per PISN number basis for one or more basic services. One or more Call Priority Interruption Capability Levels (CPICL) shall be allocated to the served user. The procedure by which CPICL is allocated is outside the scope of this Standard. CPICL shall have a value in the range 1 (lowest priority) to 3 (highest priority). An implementation may offer one or more CPICL values. NOTE 4 It is not precluded that CPICL values can be variable, e. g. a user may have the possibility to change the value with a user procedure. The details of such capabilities are outside the scope of this Standard. At least one of the methods of invoking SS-CPI (see 6.2.2.2) shall be offered.
6.2.2 Normal procedures 6.2.2.1 A c t iv a t io n /d e a c t iv a t io n /r e g is t r a t io n /in t e r r o g a t io n SS-CPI shall be activated upon provision and deactivated upon withdrawal. Registration and interrogation shall not apply.
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6.2.2.2
I n v o c a t io n a n d o p e r a t io n There are two different ways to invoke SS-CPI. A PISN may offer one or both of these ways. These are: i) Consultation: the served user, on being informed that a call has failed because of congestion en route to the destination, shall be able, within a defined period (consultation timer), to request SS-CPI. ii) Immediate invocation: the served user shall be able to request SS-CPI as part of the initial call setup, or as an implementation option, the network can invoke SS-CPI automatically on behalf of the user. On invocation, CPICL, if provided, shall be assigned one of the offered values. NOTE 5 As an example, this assignment may be based on a class of service.
6.2.2.2.1
V e r if ic a t io n a n d s e le c t io n o f a n e s t a b lis h e d c a ll If the consultation method is provided to the served user, the following procedure shall apply. If a call fails due to congestion en route to the destination and the PISN is not aware that call priority interruption is not allowed (e. g. because of insufficient CPICL), the PISN shall notify the served user that the call has failed because of congestion and that priority interruption may be possible. The served user may then request SS-CPI. If the immediate invocation method is provided to the served user, the served user may request SSCPI with the initial call set-up. For both invocation alternatives the following shall apply. Upon receiving a call priority interruption request, the PISN shall check that at least one user information channel is available on the selected route. If a user information channel is available on the selected route, the call shall proceed in accordance with basic call procedures. If no user information channel is available on the selected route, and in order to determine that interruption is allowed, the PISN shall check that the CPICL value of the received call request is greater than zero (priority call). It shall then check that the Call Priority Interruption Protection Level (CPIPL) value of an active call on the selected route is lower than the CPICL value of the served user. If the PISN does not have knowledge of the CPIPL value of an active call, this call shall be treated as if the call has no protection (i.e. CPIPL value equal to zero). NOTE 6 CPIPL values are allocated when SS-CPIP is invoked. See 7.2.2.2. The call that passes these checks shall be selected as the established call. If more than one call passes these checks, the PISN shall select the active call with the lowest CPIPL value as the established call. If more than one call has the same lowest CPIPL, the method used to select the established call from this group of calls shall be implementation dependent. If no active call passes these checks the priority call request may be rejected or some other implementation dependent action may be taken. NOTE 7 One example of an implementation dependent action is to establish the call on another route, if such a route is available. When the established call has been selected, the users in the established call may as an option be provided with an Impending priority interruption warning notification and a short delay before the user connection is broken. If this notification is provided, it shall be sent to the users in the established call and the impending priority interruption state shall be entered.
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NOTE 8 The Impending priority interruption warning notification can be accompanied by an in-band tone or announcement to all users in the established call. SS-CPI shall terminate when the call request reaches its destination or leaves the PISN. 6.2.2.2.2 Actions during impending priority interruption state 6.2.2.2.2.1 Impending priority interruption state ends A time period, time to priority interruption (1-10 seconds as an implementation option), after the Impending priority interruption warning notification has been provided, the users involved in the established call shall be notified of the forced release. The impending priority interruption state shall be terminated, the established call shall be released and the priority call request shall proceed in accordance with basic call procedures selecting the newly available user information channel. 6.2.2.2.2.2
Release of priority call request If the priority call request is released by the served user during the impending priority interruption state, the users involved in the established call shall be notified that the priority interruption request has been terminated and SS-CPI shall be terminated.
6.2.2.2.2.3
Release of established call If the established call is released by a user during the impending priority interruption state, the priority call request shall proceed in accordance with basic call procedures selecting the newly available user information channel.
6.2.2.2.2.4
User information channel becomes available If another user information channel becomes available for this call during the impending priority interruption state, the users involved in the established call shall be notified that the impending priority interruption state has been terminated. The priority call request shall proceed in accordance with basic call procedures selecting the newly available user information channel.
6.2.3 Ex c e p t io n a l p r o c e d u r e s 6.2.3.1 A c t iv a t io n /d e a c t iv a t io n /r e g is t r a t io n /in t e r r o g a t io n Not applicable. 6.2.3.2
6.3
I n v o c a t io n a n d o p e r a t io n If the interruption request cannot be accepted the request shall be ignored.
Interaction with other supplementary services and ANFs Interactions with other supplementary services and ANFs for which PISN standards were available at the time of publication of this Standard are specified below.
6.3.1
Calling Name Identification Presentation (SS-CNIP) No interaction.
6.3.2
Connected Name Identification Presentation (SS-CONP) No interaction.
6.3.3
Completion of Call to Busy Subscriber (SS-CCBS) SS-CPI may apply to a call resulting from the use of SS-CCBS.
6.3.4
Completion of Call on No Reply (SS-CCNR) SS-CPI may apply to a call resulting from the use of SS-CCNR.
6.3.5
C a ll Tr a n s f e r ( S S - C T) SS-CPI shall not be invoked to interrupt other calls during establishment of the new connection.
6.3.6
C a ll F o r wa r d in g U n c o n d it io n a l ( S S - C F U ) SS-CPI may be invoked when establishing the diverted call.
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6.3.7
C a ll F o r wa r d in g Bu s y ( S S - C F B) SS-CPI may be invoked when establishing the diverted call.
6.3.8
C a l l F o r wa r d i n g N o R e p l y ( S S - C F N R ) SS-CPI may be invoked when establishing the diverted call.
6.3.9
Call Deflection (SS-CD) SS-CPI may be invoked when establishing the diverted call.
6.3.10
Path Replacement (ANF-PR) SS-CPI shall not be invoked to interrupt other calls during establishment of the new connection.
6.3.11
C a ll O f f e r ( S S - C O ) No interaction.
6.3.12
C a ll I n t r u s io n ( S S - C I ) No interaction. NOTE 9 SS-CI may be used in conjunction with SS-CPI to provide for intrusion if a called user busy condition is determined.
6.3.13
Do not Disturb (SS-DND) No interaction.
6.3.14
Do not Disturb Override (SS-DNDO) No interaction.
6.3.15
A d v ic e o f C h a r g e ( S S - A O C ) No interaction.
6.3.16
R e c a ll ( S S - R E) No interaction.
6.3.17
Call Interception (ANF-CINT) A SS-CPI request shall have priority over any ANF-CINT request on a network congestion condition. There is no interaction with ANF-CINT for other invocation conditions.
6.3.18
Tr a n s it C o u n t e r ( A N F - TC ) No interaction.
6.3.19
Interaction with Wireless Terminal Location Registration (SS-WTLR) No interaction.
6.3.20
I n t e r a c t i o n w i t h W i r e l e s s Te r m i n a l I n c o m i n g C a l l ( A N F - W T M I ) SS-CPI may be invoked when establishing a call to a WTM user.
6.3.21
I n t e r a c t i o n w i t h W i r e l e s s Te r m i n a l O u t g o i n g C a l l ( A N F - W T M O ) No interaction.
6.3.22
Interaction with Wireless Terminal Authentication of a WTM user (SS-WTAT) No interaction.
6.3.23
Interaction with Wireless Terminal Authentication of a PISN (SS-WTAN) No interaction.
6.3.24
M e s s a g e W a it in g I n d ic a t io n ( S S - M W I ) No interaction.
6.3.25
Common Information (ANF-CMN) No interaction.
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6.3.26
6.4
C a ll P r io r it y I n t e r r u p t i o n P r o t e c t i o n ( S S - C P I P ) See 6.2.
Interworking considerations When interworking with another network which supports an equivalent feature, it may be possible to cooperate with the other network to provide SS-CPI.
6.5
Overall SDL Figure 1 contains the dynamic description of SS-CPI using the Specification and Description Language (SDL) defined in ITU-T Rec. Z.100 (1999). The SDL process represents the behaviour of the PISN in providing SS-CPI to a served user. Input symbols from the left and output symbols to the left represent primitives from and to the served user. Input symbols from the right represent inputs from the basic call process or inputs from an internal process. Output symbols to the right represent primitives to the users in the established call, outputs to the basic call process or outputs to an internal process.
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Process SS_CPI
1(3)
CPI Idle
Call request with SS−CPI request
From calling user
Network congested?
From calling user
Wait
No Call request with SS−CPI request
Call request without SS−CPI req.
Yes 1
CPI Idle
Wait
Basic call released; reason other than congestion
CPI Idle
Basic call released due to congestion
SS−CPI allowed? Yes SS−CPI possible
No CPI Idle
Start consultation timer
Consultation
F ig u r e 1 - S S - C P I , o v e r a ll S D L - P a r t 1 o f 3
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Process SS_CPI
2(3)
Consultation
Consultation timer expiry
CPI Idle
SS−CPI request
Basic call cleared
Stop consultation timer
Stop consultation timer
Ntwk. still congested?
1
No
Yes
Call request with SS−CPI request
Interruption allowed? Yes
No
CPI Idle
Select established call
CPI Idle
Warning Users in established call
CPI Idle
Notify users of impending priority interruption Start impending priority interruption timer
Impending Priority Interruption
No warning Notify users in established call of forced release
Release established call
Call request with SS−CPI request
CPI Idle
F ig u r e 1 - S S - C P I , o v e r a ll S D L - P a r t 2 o f 3
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Process SS_CPI
3(3) Impending Priority Interruption
Impending priority interruption timer expiry
User information channel available
User clears established call
Notify users in established call of forced release
Stop impending priority interruption timer
Stop impending priority interruption timer
Stop impending priority interruption timer
Release established call
Notify users in established call of SS−CPI termination
Call request with SS−CPI request
Notify users in established call of SS−CPI termination
Call request with SS−CPI request
Call request with SS−CPI request
CPI Idle
CPI Idle
CPI Idle
Served user clears priority call
CPI Idle
F ig u r e 1 - S S - C P I , o v e r a ll S D L - P a r t 3 o f 3
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7
SS-CPIP stage 1 specification
7.1
Description
7.1.1
General description Call Priority Interruption Protection (SS-CPIP) is a supplementary service that allows for the protection of calls against interruption. The served user may be either a calling user or a called user.
7.1.2
7.2
Qualifications on applicability to telecommunication services SS-CPIP is applicable to all basic services defined in ECMA-142.
Procedure
7.2.1
P r o v is io n /wit h d r a wa l SS-CPIP shall be provided or withdrawn after pre-arrangement with the service provider. SS-CPIP shall be provided on a per PISN number basis for one or more basic services. One or more Call Priority Interruption Protection Levels (CPIPL) shall be allocated to the served user. CPIPLs may be allocated to gateways to other networks for use on behalf of users outside the PISN. Where no CPIPL is allocated a default value of zero (no protection) shall be assumed. The procedure by which CPIPL is allocated is outside the scope of this Standard. CPIPL shall have a value in the range 0 (no protection) to 3 (total protection). CPIPL values 0 and 3 shall be offered, and as an implementation option values 1 and 2 may be offered. NOTE 10 It is not precluded that CPIPL values can be variable, e.g., a user may have the possibility to change the value with a user procedure. The details of such capabilities are outside the scope of this Standard.
7.2.2 Normal procedures 7.2.2.1 A c t iv a t io n /d e a c t iv a t io n /r e g is t r a t io n /in t e r r o g a t io n SS-CPIP shall be activated upon provision and deactivated upon withdrawal. Registration and interrogation shall not apply. 7.2.2.2
I n v o c a t io n a n d o p e r a t io n SS-CPIP may be invoked by a calling user or by a called user to assign a protection level (CPIPL) to a call. As an implementation option, the network can invoke SS-CPIP automatically on behalf of the served user. On invocation, a protection level (CPIPL), chosen from the offered values, shall be assigned to the call. NOTE 11 As an example, this assignment may be based on a class of service. Where both the calling user and the called user invoke SS-CPIP for the same call, the CPIPL of the call shall be assigned the higher of the values requested. The CPIPL shall be stored by the network for the lifetime of the call.
7.2.2.2.1
Invocation by a calling user The calling user shall be able to request SS-CPIP as part of the initial call set-up. Following the receipt of a call priority protection request, the PISN shall pass on the received CPIPL unchanged towards the call destination.
7.2.2.2.2
I n v o c a t io n b y a c a lle d u s e r The called user shall be able to request SS-CPIP for protection when confirming a call set-up request, to indicate a higher protection level than that associated with the incoming call. This request may be made regardless of whether, or not, the calling user invoked SS-CPIP.
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Following the receipt of a call priority protection request which requests a higher protection level, the PISN shall pass on the received CPIPL unchanged towards the origin of the call. 7.2.3 Ex c e p t io n a l p r o c e d u r e s 7.2.3.1 A c t iv a t io n /d e a c t iv a t io n /r e g is t r a t io n /in t e r r o g a t io n Not applicable. 7.2.3.2
7.3
I n v o c a t io n a n d o p e r a t io n If the protection request cannot be accepted the request shall be ignored.
Interaction with other supplementary services and ANFs Interactions with other supplementary services and ANFs for which PISN standards were available at the time of publication of this Standard are specified below.
7.3.1
Calling Name Identification Presentation (SS-CNIP) No interaction.
7.3.2
Connected Name Identification Presentation (SS-CONP) No interaction.
7.3.3
Completion of Call to Busy Subscriber (SS-CCBS) SS-CPIP may apply to a call resulting from the use of SS-CCBS.
7.3.4
Completion of Call on No Reply (SS-CCNR) SS-CPIP may apply to a call resulting from the use of SS-CCNR.
7.3.5
C a ll Tr a n s f e r ( S S - C T) When call transfer is invoked the resulting call shall assume the highest of the protection levels of the two calls involved.
7.3.6
C a ll F o r wa r d in g U n c o n d it io n a l ( S S - C F U ) SS-CPIP may be invoked when establishing the diverted call. The forwarded-to user may indicate that a higher protection level is required on the resulting call.
7.3.7
C a ll F o r wa r d in g Bu s y ( S S - C F B) SS-CPIP may be invoked when establishing the diverted call. The forwarded-to user may indicate that a higher protection level is required on the resulting call.
7.3.8
C a l l F o r wa r d i n g N o R e p l y ( S S - C F N R ) SS-CPIP may be invoked when establishing the diverted call. The forwarded-to user may indicate that a higher protection level is required on the resulting call.
7.3.9
Call Deflection (SS-CD) SS-CPIP may be invoked when establishing the diverted call. The deflected-to user may indicate that a higher protection level is required on the resulting call.
7.3.10
Path Replacement (ANF-PR) SS-CPIP may be invoked when establishing the new connection so that the new connection has the same protection level as the old one.
7.3.11
C a ll O f f e r ( S S - C O ) No interaction.
7.3.12
C a ll I n t r u s io n ( S S - C I ) No interaction.
7.3.13
Do not Disturb (SS-DND) No interaction.
7.3.14
Do not Disturb Override (SS-DNDO) No interaction.
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7.3.15
A d v ic e o f C h a r g e ( S S - A O C ) No interaction.
7.3.16
R e c a ll ( S S - R E) No interaction.
7.3.17
Call Interception (ANF-CINT) SS-CPIP may be invoked when establishing the intercepted call. The intercepted-to user may indicate that a higher protection level is required on the resulting call.
7.3.18
Tr a n s it C o u n t e r ( A N F - TC ) No interaction.
7.3.19
Interaction with Wireless Terminal Location Registration (SS-WTLR) No interaction.
7.3.20
I n t e r a c t i o n w i t h W i r e l e s s Te r m i n a l I n c o m i n g C a l l ( A N F - W T M I ) SS-CPIP may be invoked when establishing a call to a WTM user.
7.3.21
I n t e r a c t i o n w i t h W i r e l e s s Te r m i n a l O u t g o i n g C a l l ( A N F - W T M O ) No interaction.
7.3.22
Interaction with Wireless Terminal Authentication of a WTM user (SS-WTAT) No interaction.
7.3.23
Interaction with Wireless Terminal Authentication of a PISN (SS-WTAN) No interaction.
7.3.24
M e s s a g e W a it in g I n d ic a t io n ( S S - M W I ) No interaction.
7.3.25
Common Information (ANF-CMN) No interaction.
7.3.26
Call Priority Interruption (SS-CPI) See 6.2.
7.4
Interworking considerations When interworking with another network which supports an equivalent feature, it may be possible to cooperate with the other network to provide SS-CPIP.
7.5
Overall SDL Figure 2 contains the dynamic description of SS-CPIP using the Specification and Description Language (SDL) defined in ITU-T Rec. Z.100 (1999). The SDL process represents the behaviour of the PISN in providing SS-CPIP to a served user. Input symbols from the left represent primitives from the served user. Output symbols to the right represent primitives to the basic call process.
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Process SS_CPIP
1(1)
CPIP Idle
SS−CPIP request
SS−CPIP request
From calling user
SS−CPIP request
From called user
Higher PL? Yes
CPIP Idle
SS−CPIP request
No CPIP Idle
CPIP Idle
F ig u r e 2 - S S - C P I P , o v e r a ll S D L - P a r t 1 o f 1
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8
SS-CPI stage 2 specification
8.1
Functional model
8.1.1
Functional model description The functional model shall comprise the following Functional Entities (FE): FE1
Served user agent;
FE2
Served user's control entity;
FE3
SS-CPI detection and execution entity;
FE4
Established call user's control entity;
FE5
Established call user's agent.
The following functional relationships shall exist between these FEs: ra
between FE1 and FE2;
rb
between FE2 and FE3 and between a pair of FE3s;
rc
between FE3 and FE4s;
rd
between FE4 and FE5;
Figure 3 shows these FEs and relationships.
NOTE Functional entities shown within square brackets repeat as necessary. There is one FE4 and FE5 per user (usually two) in the established call.
F ig u r e 3 - F u n c t io n a l m o d e l f o r S S - C P I 8.1.2 D e s c r ip t io n o f F u n c t io n a l En t it ie s 8.1.2.1 S e r v e d u s e r a g e n t , F E1 This functional entity: • receives requests from the served user and passes these on to FE2; • receives information from FE2 and passes it on to the served user. 8.1.2.2
Served user's control entity, FE2 This functional entity: • at the time of original basic call r1_SETUP-request/indication: − receives and validates request from FE1 for immediate invocation of SS-CPI; − determines if immediate invocation or consultation is applicable for the call; − if SS-CPI is applicable for the call, sends an immediate invocation request to FE3 at the time of the original basic call r2_SETUP-request/indication;
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• if consultation applies to the call and all conditions for performing consultation are met: − informs FE1 that the original call has encountered congestion and that SS-CPI may be requested; − limits the length of the consultation by clearing the call if the served user has not responded, by clearing the call or requesting SS-CPI, within the consultation time; − receives request, during consultation, from FE1 for invocation of SS-CPI and sends an appropriate SS-CPI invocation request to FE3. 8.1.2.3
S S - C P I d e t e c t io n a n d e x e c u t io n e n t it y , F E3 This functional entity: • on an incoming call with a SS-CPI request checks: − for available resources on the selected route; − if the necessary resources are not available, optionally sends notifications, releases the established call with the lowest priority (see also 6.2.2.2.1); − establishes the priority call by sending an invocation request to the next FE3 at the time of the original basic call r2_SETUP-request/indication.
8.1.2.4
Established call user's control entity, FE4 This functional entity: • receives information flows from FE3 and forwards these to FE5.
8.1.2.5
Es t a b lis h e d c a ll u s e r 's a g e n t , F E5 This functional entity: • receives information flows from FE4 and informs the user.
8.1.3
R e la t io n s h ip o f f u n c t io n a l m o d e l t o b a s ic c a ll f u n c t io n a l m o d e l An example of a relationship between the FEs for SS-CPI and the FEs for the basic call is shown in figure 4.
NOTE Functional entities shown within square brackets repeat as necessary. There is one FE4 and FE5 per user (usually two) in the established call. Figure 4 - Example relationship between the model for SS-CPI and basic call
8.2 8.2.1
Information flows D e f in it io n o f in f o r m a t io n f lo ws In the tables listing the elements in information flows, the column headed "Request" indicates which of these elements are mandatory (M) and which are optional (O) in a request/indication information.
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8.2.1.1 R e la t io n s h ip r a 8.2.1.1.1 ra_INFORM ra_INFORM is an unconfirmed information flow sent across ra from FE2 to FE1. It is used to inform FE1 that congestion has been encountered and that SS-CPI may be requested. There are no elements within the ra_INFORM information flow. 8.2.1.1.2
ra_CPI_INV ra_CPI_INV is an unconfirmed information flow sent across ra from FE1 to FE2. It is used to invoke priority interruption. Table 1 lists the elements within the ra_CPI_INV information flow. Ta b le 1 - C o n t e n t o f r a _ C P I _ I N V Element
Request
CPICL
O (NOTE 12)
NOTE 12 Between FE1 and FE2 this element may be omitted in the case that the served user does not have the capability to change or select CPICL. This element shall be included if and only if interruption is invoked. This element shall have a value in the range 1 (lowest priority) to 3 (highest priority). 8.2.1.2 R e la t io n s h ip r b 8.2.1.2.1 rb_CPI_INV rb_CPI_INV is an unconfirmed information flow sent across rb from FE2 to FE3, and from FE3 to a subsequent FE3. It is used to invoke priority interruption. Table 2 lists the elements within the rb_CPI_INV information flow. Ta b le 2 - C o n t e n t o f r b _ C P I _ I N V Element
Request
CPICL
M (NOTE 13)
NOTE 13 This element shall have a value in the range 1 (lowest priority) to 3 (highest priority). 8.2.1.3 R e la t io n s h ip r c 8 . 2 . 1 . 3 . 1 r c _ C P I _ TER M rc_CPI_TERM is an unconfirmed information flow sent across rc from FE3 to each FE4. It is used to inform FE4 that the impending priority interruption state has been terminated. There are no elements within the rc_CPI_TERM information flow. 8.2.1.3.2
rc_CPI_WARN rc_CPI_WARN is an unconfirmed information flow sent across rc from FE3 to each FE4. It is used to inform FE4 that priority interruption is impending. There are no elements within the rc_CPI_WARN information flow.
8.2.1.3.3
r c _ F O R C ED _ R EL rc_FORCED_REL is an unconfirmed information flow sent across rc from FE3 to FE4. It is used to inform FE4 that its associated user has been force released. There are no elements within the rc_FORCED_REL information flow.
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8.2.1.4 R e la t io n s h ip r d 8 . 2 . 1 . 4 . 1 r d _ C P I _ TER M rd_CPI_TERM is an unconfirmed information flow sent across rd from FE4 to FE5. It is used to inform FE5 that the impending priority interruption state has been terminated. There are no elements within the rd_CPI_TERM information flow. 8.2.1.4.2
rd_CPI_WARN rd_CPI_WARN is an unconfirmed information flow sent across rd from FE4 to FE5. It is used to inform FE5 that priority interruption is impending. There are no elements within the rd_CPI_WARN information flow.
8.2.1.4.3
r d _ F O R C ED _ R EL rd_FORCED_REL is an unconfirmed information flow sent across rd from FE4 to FE5. It is used to inform FE5 that its associated user has been force released. There are no elements within the rd_FORCED_REL information flow.
8.2.2
R e la t io n s h ip o f in f o r m a t io n f lo ws t o b a s ic c a ll in f o r m a t io n f lo ws Table 3 summarises the relationships of the SS-CPI information flows with those of the basic call. T a b l e 3 - R e l a t i o n s h i p o f t h e S S - C P I i n f o r m a t i o n f l o ws wit h t h e b a s i c c a l l Information flow
ra
With basic call flow
Basic call flows
ra_INFORM
request
yes
no
ra_CPI_INV
request
yes
yes
r1_SETUP req/ind
rb
rb_CPI_INV
request
no
yes
r2_SETUP req/ind
rc
rc_CPI_TERM
request
yes
no
rc_CPI_WARN
request
yes
no
rc_FORCED_REL
request
no
yes
rd_CPI_TERM
request
yes
no
rd_CPI_WARN
request
yes
no
rd_FORCED_REL
request
no
yes
rd
8.2.3
Independent of basic call flow
r2_RELEASE req/ind
r1/r3_DISCONNECT req/ind
I n f o r m a t io n f lo w s e q u e n c e s A stage 3 standard for SS-CPI shall provide signalling procedures in support of the information flow sequences specified below. In addition, signalling procedures should be provided to cover other sequences arising from error situations, interactions with basic call, interactions with other supplementary services, different topologies, etc. In the figures, SS-CPI information flows are represented by solid arrows and basic call information flows are represented by broken arrows. An ellipse embracing two information flows indicates that the two information flows occur simultaneously. Within a column representing a SS-CPI functional entity, the numbers refer to functional entity actions listed in 8.3. The following abbreviations are used: req
request;
ind
indication;
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The following timers are used: T1
Consultation timer;
T2
Impending priority interruption timer.
8.2.3.1
FE1 CCA
911
912
N o r m a l o p e r a t io n , c o n s u lt a t io n Figure 5 shows the information flow sequence for a successful priority interruption attempt using consultation. ra r1
FE2 CC
r1_SETUP req/ind
921
ra_INFORM req/ind
922 T1
ra_CPI_INV req/ind
923
rb r2
FE3 CC
rc r2
FE4 CC
rd r1/r3
FE5 CCA
r2_SETUP req/ind r2_RELEASE req/ind
rb_CPI_INV req/ind r2_SETUP req/ind
931 932 933 T2
934
rc_CPI_WARN req/ind
941
rd_CPI_WARN req/ind
951
rc_ FORCED_REL req/ind r2_RELEASE 942 req/ind
rd_ FORCED_REL 952 req/ind r1/r3_ DISCONNECT req/ind
935
rb_CPI_INV req/ind r2_SETUP req/ind
To next FE3 and CC
Figure 5 - Information flow sequence for SS-CPI - normal operation, consultation
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8.2.3.2
FE1 CCA
912
Normal operation, immediate invocation Figure 6 shows the information flow sequence for a successful priority interruption attempt using immediate invocation. ra r1
FE2 CC
rb r2
FE3 CC
rc r2
FE4 CC
rd r1/r3
FE5 CCA
ra_CPI_INV req/ind r1_SETUP req/ind
924
rb_CPI_INV req/ind r2_SETUP req/ind
931 932 933 T2
934
rc_CPI_WARN req/ind
941
rd_CPI_WARN req/ind
951
rc_ FORCED_REL req/ind r2_RELEASE 942 req/ind
rd_ FORCED_REL 952 req/ind r1/r3_ DISCONNECT req/ind
935
rb_CPI_INV req/ind r2_SETUP req/ind
To next FE3 and CC
Figure 6 - Information flow sequence for SS-CPI - normal operation, immediate invocation
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8.2.3.3
FE1 CCA
N o r m a l o p e r a t io n , s e r v e d u s e r r e l e a s e s t h e p r i o r i t y c a l l Figure 7 shows the information flow sequence when the priority call is released by the served user during the impending priority interruption state. ra
FE2
r1
CC
rb r2
FE3 CC
rc r2
FE4 CC
rd r1/r3
FE5 CCA
PRIORITY INTERRUPTION IMPENDING r1_RELEASE req/ind
r2_RELEASE req/ind 936
rc_CPI_TERM req/ind
943
rd_CPI_TERM req/ind
953
PRIORITY INTERRUPTION TERMINATED; ESTABLISHED CALL RETAINED
Figure 7 - Information flow sequence for SS-CPI - normal operation, priority call released during impending priority interruption state 8.2.3.4
FE1 CCA
N o r m a l o p e r a t io n , u s e r in f o r m a t i o n c h a n n e l b e c o m e s a v a i l a b l e Figure 8 shows the information flow sequence when a user information channel becomes available during the impending priority interruption state. ra r1
FE2 CC
rb r2
FE3 CC
rc r2
FE4 CC
rd r1/r3
FE5 CCA
PRIORITY INTERRUPTION IMPENDING
937
rc_CPI_TERM req/ind
943
rd_CPI_TERM req/ind
953
PRIORITY INTERRUPTION TERMINATED; ESTABLISHED CALL RETAINED
935
rb_CPI_INV req/ind r2_SETUP req/ind
To next FE3 and CC
Figure 8 - Information flow sequence for SS-CPI - normal operation, user information channel becomes available during impending priority interruption state
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8.3
Functional Entity actions The following FE actions shall occur at the points indicated in the figures of 8.2.3.
8.3.1
A c t io n s o f F E1 911: The FE shall receive a ra_INFORM req/ind information flow and inform the served user that congestion has been encountered and that priority interruption may be requested. 912:
8.3.2
8.3.3
8.3.4
The FE shall receive the user's request for call priority interruption and send a ra_CPI_INV req/ind information flow to FE2, optionally including a CPICL.
A c t io n s o f F E2 921: All information in the basic call r1_SETUP req/ind information flow shall be retained. 922:
On receipt of r2_RELEASE_req/ind indicating congestion, the FE shall check whether the user is provided with SS-CPI using the consultation method and, if provided, shall start timer T1 (consultation timer) and store the call information for the duration of T1. The FE shall send a ra_INFORM req/ind flow to FE1. If the user is not provided with the interruption procedure of SS-CPI using the consultation method, the FE shall cause the call to be released.
923:
The FE shall receive the ra_CPI_INV req/ind information flow from FE1. The FE shall stop the timer T1 and send a rb_CPI_INV req/ind information flow including a CPICL to FE3. If a CPICL has been included in the ra_CPI_INV req/ind information flow received from FE1, this CPICL shall be included in the rb_CPI_INV req/ind information flow sent to FE3.
924:
The FE shall receive the ra_CPI_INV req/ind information flow from FE1 and check whether the user is provided with SS-CPI using the immediate invocation method. If provided, the FE shall send a rb_CPI_INV req/ind information flow including a CPICL to FE3. If a CPICL has been included in the ra_CPI_INV req/ind information flow received from FE1, this CPICL shall be included in the rb_CPI_INV req/ind information flow sent to FE3. If the user is not provided with SS-CPI using the immediate invocation method, the FE shall ignore the ra_CPI_INV req/ind information flow received from FE1.
A c t io n s o f F E3 931: The FE shall receive the rb_CPI_INV req/ind information flow from FE2 or from a previous FE3. 932:
The FE shall compare the CPICL with the CPIPLs for all active calls on the selected route and shall determine whether priority interruption is allowed or not.
933:
If priority interruption is allowed, the FE shall either send a rc_CPI_WARN req/ind information flow to each FE4 and start timer T2 (impending priority interruption timer) or shall release the established call immediately and send a rc_FORCED_REL req/ind information flow to the FE4s.
934:
When timer T2 has elapsed, the FE shall release the established call and send a rc_FORCED_REL req/ind information flow to the FE4s.
935:
The FE shall send a rb_CPI_INV req/ind information flow including the received CPICL to the next FE3.
936:
If the priority call is released during the impending priority interruption state, the FE shall send the rc_CPI_TERM req/ind information flow to each FE4 and terminate the impending priority interruption state. The established call shall revert back to the state that existed before the warning took place.
937:
If a user information channel becomes available during the impending priority interruption state, the FE shall send the rc_CPI_TERM req/ind information flow to each FE4 and terminate the impending priority interruption state. The established call shall revert back to the state that existed before the warning took place.
A c t io n s o f F E4 941: The FE shall receive the rc_CPI_WARN req/ind information flow from FE3 and send a rd_CPI_WARN req/ind information flow to FE5.
- 24 -
8.3.5
8.4
942:
The FE shall receive the rc_FORCED_REL req/ind information flow from FE3 and send a rd_FORCED_REL req/ind information flow to FE5.
943:
The FE shall receive the rc_CPI_TERM req/ind information flow from FE3 and send a rd_CPI_TERM req/ind information flow to FE5.
A c t io n s o f F E5 951: The FE shall receive the rd_CPI_WARN req/ind information flow from FE4 and provide the user with the impending priority interruption warning notification. 952:
The FE shall receive the rd_FORCED_REL req/ind information flow from FE4 and inform the user.
953:
The FE shall receive the rd_CPI_TERM req/ind information flow from FE4 and inform the user.
Functional entity behaviour The FE behaviours shown below are intended to illustrate typical FE behaviour in terms of information flows sent and received. The behaviour of each FE is shown using the Specification and Description Language (SDL) defined in ITU-T Rec. Z.100 (1999).
8.4.1
Be h a v io u r o f F E1 Figure 9 shows the normal behaviour of FE1. Input symbols from the left and output symbols to the left represent primitives from and to the served user. Input symbols from the right and output symbols to the right represent information flows from and to FE2.
- 25 -
Process CPI_FE1
1(1)
CPI Idle
as part of initial call setup
Priority interruption request
ra_INFORM req/ind
911, ra, FE2
Inform user about priority interruption possibility
Wait for user response on inform
Served user requests priority interruption
with or without basic call r1_SETUP req/ind
ra_CPI_INV req/ind
912, ra, FE2
CPI Idle
F ig u r e 9 - S S - C P I , S D L f o r F E1
- 26 -
8.4.2
Be h a v io u r o f F E2 Figure 10 shows the normal behaviour of FE2. Input symbols from the left and output symbols to the left represent information flows from and to FE1. Input symbols from the right and output symbols to the right represent information flows from and to FE3 and signals from and to the collocated CC.
Process CPI_FE2
1(1)
CPI Idle
with basic call r1_SETUP req/ind
ra_CPI_INV req/ind
924, ra, FE1
without ra_CPI_INV req/ind
Call request from collocated CC
921, ra, FE1
Interruption with immediate invocation provided? Yes with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
No Consultation provided?
924, rb, FE3
CPI Idle
for reasons other than no circuit/ channel available (from collocated CC
Basic call released
due to no circuit/ channel available (from collocated CC)
Basic call released
ra_INFORM req/ind
CPI Idle
Yes Retain all information from basic call SETUP
Basic call to proceed
No
Pending Consultation
CPI Idle
922, rb, FE3
Basic call proceeding
922, ra, FE1
CPI Idle
923, ra, FE1
Basic call released (from collocated CC)
923, rb, FE3
Stop timer T1
Start timer T1
Wait for CPI_INV
Timer T1 expires
Release basic call towards CCA
CPI Idle
ra_CPI_INV req/ind
with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
Stop timer T1
CPI Idle
F ig u r e 1 0 - S S - C P I , S D L f o r F E2
CPI Idle
- 27 -
8.4.3
Be h a v io u r o f F E3 Figure 11 shows the normal behaviour of FE3. Input symbols from the left represent information flows from FE2. Input symbols from the right and output symbols to the right represent information flows from and to FE4 and signals from and to the collocated CC.
Process CPI_FE3
1(2)
CPI Idle
with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
931, rb, FE2
User information channel available on selected route? No FE compares CPICL with CPIPLs of active calls on selected route. If higher than at least one, interruption is allowed.
Yes Interruption allowed? Yes Select active call with lowest CPIPL as the established call
No Basic call to proceed
CPI Idle
Warning
rc_CPI_WARN req/ind
Start timer T2
Impending Priority Interruption
No warning
933, rc, FE4
with basic call r2_RELEASE req/ind
rc_FORCED_REL req/ind
934, rc, FE4
with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
935, rb, FE3
CPI Idle
F ig u r e 1 1 - S S - C P I , S D L f o r F E3 - P a r t 1 o f 2
- 28 -
Process CPI_FE3
2(2)
Impending Priority Interruption
Established call released (from collocated CC)
Timer T2 expires
with basic call r2_RELEASE req/ind
rc_FORCED_ _REL req/ind
934, rc, FE4
with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
935, rb, FE3
Stop timer T2
with basic call r2_SETUP req/ind
rb_CPI_INV req/ind
CPI Idle
CPI Idle
Priority call released (from collocated CC)
User information channel available on selected route
Stop timer T2
Stop timer T2
rc_CPI_TERM req/ind
CPI Idle
936, rc, FE4
with basic call r2_SETUP req/ind
rc_CPI_TERM req/ind
937, rc, FE4
rb_CPI_INV req/ind
935, rb, FE3
CPI Idle
F ig u r e 1 1 - S S - C P I , S D L f o r F E3 - P a r t 2 o f 2
935, rb, FE3
- 29 -
8.4.4
Be h a v io u r o f F E4 Figure 12 shows the normal behaviour of FE4. Input symbols from the left represent information flows from FE3. Output symbols to the right represent information flows to FE5.
Process CPI_FE4
1(1)
CPI Idle
rc_CPI_ _WARN req/ind
941, rc, FE3
rc_CPI_ _TERM req/ind
943, rc, FE3
rd_CPI _WARN req/ind
941, rd, FE5
rd_CPI_TERM req/ind
943, rd, FE5
CPI Idle
CPI Idle
with basic call r2_RELEASE req/ind
with basic call r1/r3_DISCONNECT req/ind
rc_FORCED_ _REL req/ind
rd_FORCED_ _REL req/ind
942, rc, FE3
942, rd, FE5
CPI Idle
F ig u r e 1 2 - S S - C P I , S D L f o r F E4
- 30 -
8.4.5
Be h a v io u r o f F E5 Figure 13 shows the normal behaviour of FE5. Input symbols from the left represent information flows from FE4. Output symbols to the right represent primitives to the user.
Process CPI_FE5
1(1)
CPI Idle
rd_CPI_ _WARN req/ind
rd_CPI_ _TERM req/ind
951, rd, FE4
Warn user of impending priority interruption
Inform user of termination of impending interruption
CPI Idle
CPI Idle
with basic call r1/r3_DISCONNECT req/ind
rd_FORCED_ _REL req/ind
952, rd, FE4
Inform user of forced release
CPI Idle
F ig u r e 1 3 - S S - C P I , S D L f o r F E5
953, rd, FE4
- 31 -
8.5
Allocation of Functional Entities to physical equipment Table 4 shows the allocation of Functional Entities to physical equipment. In this table, “TE“ indicates a TE attached to a PISN. Where a terminal involved is stimulus with respect to SS-CPI, any TE shown as residing in the corresponding user’s TE, shall reside instead in that user’s PINX. T a b l e 4 - S c e n a r i o s f o r t h e a l l o c a t io n o f F E s t o p h y s i c a l e q u i p m e n t
8.6
Scenario
FE1
FE2
FE3
FE4
FE5
1
Served user TE
Served user PINX
Transit PINX
Established call user's PINX
Established call user's TE
2
Served user TE
Served user PINX
Served user PINX
Established call user's PINX
Established call user's TE
Interworking considerations SS-CPI applies only to portions of a call that lie within the PISN. For calls to and from other networks the Functional Entities are allocated to physical equipment as shown in table 5. T a b l e 5 - S c e n a r i o s f o r t h e a l l o c a t i o n o f F Es t o p h y s i c a l e q u i p m e n t f o r n o r m a l o p e r a t i o n in c a s e o f in t e r wo r k in g wit h a n o t h e r n e t wo r k
9
Scenario
FE1
FE2
FE3
FE4
FE5
3
Other network
Other network
Incoming Gateway PINX
Established call user's PINX
Established call user's TE
4
Served user TE
Served user PINX
Transit PINX
Outgoing Gateway PINX
Other network
5
Served user TE
Served user PINX
Served user PINX
Outgoing Gateway PINX
Other network
SS-CPIP stage 2 specification
9.1 9.1.1
Functional model Functional model description The functional model shall comprise the following Functional Entities (FE): FE1
Calling user agent;
FE2
Calling user's control entity;
FE3
SS-CPIP transit entity;
FE4
Called user’s control entity;
FE5
Called user agent.
The following functional relationships shall exist between these FEs: ra
between FE1 and FE2;
rb
between FE2 and FE4, between FE2 and FE3, between a pair of FE3s, and between FE3 and FE4;
rc
between FE4 and FE5.
Figure 14 shows these FEs and relationships.
- 32 -
NOTE Functional entities shown within square brackets may be absent or may repeat as necessary.
F ig u r e 1 4 - F u n c t io n a l m o d e l f o r S S - C P I P 9.1.2 D e s c r ip t io n o f F u n c t io n a l En t it ie s 9.1.2.1 Calling user agent, FE1 This functional entity: • receives protection requests from the calling user and passes these on to FE2. 9.1.2.2
Calling user's control entity, FE2 This functional entity: • receives and validates requests from FE1 for forward invocation of SS-CPIP; • if SS-CPIP is applicable for the call, sends an invocation request ("forward invocation request") to FE3 or FE4 at the time of the original basic call r2_SETUP-request/indication; • receives backward invocation requests from FE3 or FE4; • saves the protection level for the call.
9.1.2.3
S S - C P I P t r a n s it e n t it y , F E3 This functional entity: • on an incoming call with a SS-CPIP request sends a forward invocation request to the next FE3 or to an FE4 at the time of the original basic call r2_SETUP-request/indication; • receives backward invocation requests from FE4, or a subsequent FE3, and passes them on to FE2, or a preceding FE3; • saves the protection level for the call.
9.1.2.4
C a lle d u s e r 's c o n t r o l e n t it y , F E4 This functional entity: • receives forward invocation requests from FE2 or FE3; • receives and validates requests from FE5 for invocation of SS-CPIP in the backward direction; • if SS-CPIP is applicable in the backward direction (i.e., if the protection level requested by the called user is higher than that requested by the calling user), sends an invocation request ("backward invocation request") to FE2 or FE3 at the time of the r2_SETUP-response/confirm information flows; • saves the protection level for the call.
9.1.2.5
C a lle d u s e r a g e n t , F E5 This functional entity: • receives protection requests from the called user and passes these on to FE4.
9.1.3
R e la t io n s h ip o f f u n c t io n a l m o d e l t o b a s ic c a ll f u n c t io n a l m o d e l An example of a relationship between the FEs for SS-CPIP and the FEs for the basic call is shown in figure 15.
- 33 -
NOTE Functional entities shown within square brackets may be absent or may repeat as necessary.
F ig u r e 1 5 - Ex a m p le r e la t io n s h i p b e t w e e n t h e m o d e l f o r S S - C P I P a n d b a s i c c a l l
9.2
Information flows
9.2.1
D e f in it io n o f in f o r m a t io n f lo ws In the tables listing the elements in information flows, the column headed "Request" indicates which of these elements are mandatory (M) and which are optional (O) in a request/indication information.
9.2.1.1 R e la t io n s h ip r a 9.2.1.1.1 ra_CPIP_F_INV ra_CPIP_F_INV is an unconfirmed information flow sent across ra from FE1 to FE2. It is used to invoke protection in the forward direction. Table 6 lists the elements within the ra_CPIP_F_INV information flow. Ta b le 6 - C o n t e n t o f r a _ C P I P _ F _ I N V Element
Request
CPIPL
O (NOTE 14)
NOTE 14 Between FE1 and FE2 this element may be omitted in the case that the calling user does not have the capability to change or select CPIPL. This element shall have a value in the range 0 (no protection) to 3 (total protection). 9.2.1.2 R e la t io n s h ip r b 9.2.1.2.1 rb_CPIP_F_INV rb_CPIP_F_INV is an unconfirmed information flow sent across rb from FE2 to FE4, from FE2 to FE3, from FE3 to a subsequent FE3, and from FE3 to FE4. It is used to invoke protection in the forward direction. Table 7 lists the elements within the rb_CPIP_F_INV information flow. Table 7 - Content of rb_CPIP_F_INV Element
Request
CPIPL
M (NOTE 15)
NOTE 15 This element shall have a value in the range 0 (no protection) to 3 (total protection). 9.2.1.2.2
r b _ C P I P _ B_ I N V rb_CPIP_B_INV is an unconfirmed information flow sent across rb from FE4 to FE2, from FE4 to FE3, from FE3 to a subsequent FE3, and from FE3 to FE2. It is used to invoke protection in the backward direction. Table 8 lists the elements within the rb_CPIP_B_INV information flow.
- 34 -
Table 8 - Content of rb_CPIP_B_INV Element
Request
CPIPL
M (NOTE 16)
NOTE 16 This element shall have a value in the range 0 (no protection) to 3 (total protection). 9.2.1.3 R e la t io n s h ip r c 9 . 2 . 1 . 3 . 1 r c _ C P I P _ B_ I N V rc_CPIP_B_INV is an unconfirmed information flow sent across rc from FE5 to FE4. It is used to invoke protection in the backward direction. Table 9 lists the elements within the rc_CPIP_B_INV information flow. Ta b le 9 - C o n t e n t o f r c _ C P I P _ B_ I N V Element
Request
CPIPL
O (NOTE 17)
NOTE 17 Between FE5 and FE4 this element may be omitted in the case that the called user does not have the capability to change or select CPIPL. This element shall have a value in the range 0 (no protection) to 3 (total protection). 9.2.2
R e la t io n s h ip o f in f o r m a t io n f lo ws t o b a s ic c a ll in f o r m a t io n f lo ws Table 10 summarises the relationships of the SS-CPIP information flows with those of the basic call. T a b l e 1 0 - R e l a t i o n s h i p o f t h e S S - C P I P i n f o r m a t i o n f l o ws wit h t h e b a s i c c a l l Information flow
With basic call flow
Basic call flows
ra
ra_CPIP_F_INV
request
no
yes
r1_SETUP req/ind
rb
rb_CPIP_F_INV
request
no
yes
r2_SETUP req/ind
rb_CPIP_B_INV
request
no
yes
r2_SETUP resp/conf
rc_CPIP_B_INV
request
no
yes
r3_SETUP resp/conf
rc 9.2.3
Independent of basic call flow
I n f o r m a t io n f lo w s e q u e n c e s A stage 3 standard for SS-CPIP shall provide signalling procedures in support of the information flow sequences specified below. In addition, signalling procedures should be provided to cover other sequences arising from error situations, interactions with basic call, interactions with other supplementary services, different topologies, etc. In the figures, SS-CPIP information flows are represented by solid arrows and basic call information flows are represented by broken arrows. An ellipse embracing two information flows indicates that the two information flows occur simultaneously. Within a column representing a SS-CPIP functional entity, the numbers refer to functional entity actions listed in 9.3 The following abbreviations are used: req
request;
ind
indication;
- 35 -
9.2.3.1
Normal operation, forward direction Figure 16 shows the information flow sequence for a successful protection attempt invoked in the forward direction. FE1 CCA
911
ra r1
FE2 CC
rb r2
FE3 CC
rb r2
FE4 CC
rc r3
FE5 CCA
ra_CPIP_F_INV req/ind r1_SETUP req/ind
921
rb_CPIP_F_INV req/ind r2_SETUP req/ind
rb_CPIP_F_INV 931
req/ind r2_SETUP req/ind
941
Figure 16 - Information flow sequence for SS-CPIP - normal operation, forward direction
- 36 -
9.2.3.2
Normal operation, both directions Figure 17 shows the information flow sequence for a successful protection attempt invoked in both directions. FE1 CCA
911
ra r1
FE2 CC
rb r2
FE3 CC
rb r2
FE4 CC
rc r3
FE5 CCA
ra_CPIP_F_INV req/ind r1_SETUP req/ind
rb_CPIP_F_INV 921
req/ind r2_SETUP req/ind
rb_CPIP_F_INV 931
req/ind r2_SETUP req/ind
rb_CPIP_B_INV req/ind r2_SETUP
rb_CPIP_B_INV r1_SETUP resp/conf
922
req/ind r2_SETUP
932
r3_SETUP 941
req/ind rc_CPIP_B_INV req/ind r3_SETUP
942
951
resp/conf
resp/conf
resp/conf
Figure 17 - Information flow sequence for SS-CPIP - normal operation, both directions
- 37 -
9.2.3.3
Normal operation, backward direction Figure 18 shows the information flow sequence for a successful protection attempt invoked in the backward direction. FE1 CCA
ra r1
rb
FE2
r2
CC
FE3 CC
rb r2
FE4 CC
rc r3
FE5 CCA
r1_SETUP req/ind r2_SETUP req/ind r2_SETUP
r3_SETUP
req/ind
req/ind rc_CPIP_B_INV
rb_CPIP_B_INV req/ind r2_SETUP
rb_CPIP_B_INV
r1_SETUP resp/conf
922
req/ind r2_SETUP
932
req/ind r3_SETUP 942
951
resp/conf
resp/conf
resp/conf
Figure 18 - Information flow sequence for SS-CPIP - normal operation, backward direction
9.3
Functional Entity actions The following FE actions shall occur at the points indicated in the figures of 9.2.3.
9.3.1
A c t io n s o f F E1 911: The FE shall receive the user's request for call protection and send a ra_CPIP_F_INV req/ind to FE2, optionally including CPIPL.
9.3.2
A c t io n s o f F E2 921: The FE shall receive the ra_CPIP_F_INV req/ind information flow from FE1 and check whether the user is provided with the forward invocation procedure of SS-CPIP. If provided, the FE shall send a rb_CPIP_F_INV req/ind information flow including a CPIPL to FE4 or FE3. If a CPIPL has been included in the ra_CPIP_F_INV req/ind information flow received from FE1, this CPIPL shall be included in the rb_CPIP_F_INV req/ind information flow sent to FE4 or FE3. The FE shall save the protection level of the call. If the user is not provided with the forward invocation procedure of SS-CPIP, the FE shall ignore the ra_CPIP_F_INV req/ind information flow received from FE1. 922:
9.3.3
The FE shall receive the rb_CPIP_B_INV req/ind information flow from FE4 or FE3. The FE shall save the value of the CPIPL included in the rb_CPIP_B_INV req/ind information flow as the protection level for the duration of the call.
A c t io n s o f F E3 931: The FE shall receive the rb_CPIP_F_INV req/ind information flow from FE2 or from a previous FE3, and shall store the CPIPL value as the protection level for the duration of the call. The FE shall send a rb_CPIP_F_INV req/ind information flow including the received CPIPL to the next FE3 (if there is one) or to FE4.
- 38 -
932:
The FE shall receive the rb_CPIP_B_INV req/ind information flow from FE4 or from a previous FE3. The FE shall save the value of the CPIPL included in the rb_CPIP_B_INV req/ind information flow as the protection level for the duration of the call. The FE shall send a rb_CPIP_INV req/ind information flow including the received CPIPL to the next FE3 (if there is one) or to FE2.
9.3.4
A c t io n s o f F E4 941: The FE shall receive the rb_CPIP_F_INV req/ind information flow from FE2 or from a previous FE3, and shall store the CPIPL value as the protection level for the duration of the call. 942:
The FE shall receive the rc_CPIP_B_INV req/ind information flow from FE5 and check whether the user is provided with the backward invocation procedure of SS-CPIP. The FE shall also check whether a CPIPL has been included in the rc_CPIP_B_INV req/ind information flow received from FE5. If the backward invocation procedure is provided, and if the CPIPL has a higher value than that already saved for the call, the FE shall save this value as the protection level for the duration of the call. The FE shall send a rb_CPIP_B_INV req/ind information flow including a CPIPL to FE3 or FE2. If a CPIPL has been included in the rc_CPIP_B_INV req/ind information flow received from FE5, this CPIPL shall be included in the rb_CPIP_B_INV req/ind information flow sent to FE3 or FE2. If the user is not provided with the backward invocation procedure of SS-CPIP, or if the CPIPL does not have a higher value than that already saved for the call, the FE shall ignore the rc_CPIP_B_INV req/ind information flow received from FE5.
9.3.5
9.4
A c t io n s o f F E5 951: The FE shall receive the user's request for call protection and send a rc_CPIP_B_INV req/ind to FE4, optionally including CPIPL.
Functional entity behaviour The FE behaviours shown below are intended to illustrate typical FE behaviour in terms of information flows sent and received. The behaviour of each FE is shown using the Specification and Description Language (SDL) defined in ITU-T Rec. Z.100 (1999).
- 39 -
9.4.1
Be h a v io u r o f F E1 Figure 19 shows the normal behaviour of FE1. Input symbols from the left and output symbols to the left represent primitives from and to the calling user. Input symbols from the right and output symbols to the right represent information flows from and to FE2.
Process CPIP_FE1
1(1)
CPIP Idle
as part of initial call setup
Priority protection request
with or without basic call r1_SETUP req/ind
ra_CPIP_F_INV req/ind
911, ra, FE2
CPIP Idle
F ig u r e 1 9 - S S - C P I P , S D L f o r F E1
- 40 -
9.4.2
Be h a v io u r o f F E2 Figure 20 shows the normal behaviour of FE2. Input symbols from the left and output symbols to the left represent information flows from and to FE1. Input symbols from the right and output symbols to the right represent information flows from and to FE3 or FE4 and signals from and to the collocated CC.
Process CPIP_FE2
1(1)
CPIP Idle
with basic call r1_SETUP req/ind
ra_CPIP_F_ _INV req/ind
with basic call r2_SETUP resp/conf
921, ra, FE1
rb_CPIP_B_ _INV req/ind
forward invocation procedure provided?
with basic call r2_SETUP req/ind
Store CPIPL
Yes
No
Store CPIPL
Basic call to proceed
rb_CPIP_F_INV req/ind
921, rb, FE3/4
CPIP Idle
CPIP Idle
F ig u r e 2 0 - S S - C P I P , S D L f o r F E2
CPIP Idle
922, rb, FE3/4
- 41 -
9.4.3
Be h a v io u r o f F E3 Figure 21 shows the normal behaviour of FE3. Input symbols from the left represent information flows from FE2. Input symbols from the right and output symbols to the right represent information flows from and to FE4.
Process CPIP_FE3
1(1)
CPIP Idle
with basic call r2_SETUP req/ind
rb_CPIP_F_ _INV req/ind
931, rb, FE2
with basic call r2_SETUP resp/conf
rb_CPIP_B_ _INV req/ind
Store CPIPL
with basic call r2_SETUP req/ind
rb_CPIP_F_INV req/ind
932, rb, FE3/4
Store CPIPL
931, rb, FE3/4
with basic call r2_SETUP resp/conf
CPIP Idle
F ig u r e 2 1 - S S - C P I P , S D L f o r F E3
rb_CPIP_B_ _INV req/ind
CPIP Idle
932, rb, FE2/3
- 42 -
9.4.4
Be h a v io u r o f F E4 Figure 22 shows the normal behaviour of FE4. Input symbols from the left represent information flows from FE3 or FE2. Input symbols from the right represent information flows from FE5. Output symbols to the left represent information flows to FE3 or FE2.
Process CPIP_FE4
1(1)
CPIP Idle
with basic call r2_SETUP req/ind
rb_CPIP_F_ _INV req/ind
941, rb, FE2/3
with basic call r2_SETUP resp/conf
Store CPIPL
Backward invocation procedure provided?
CPIP Idle
FE compares CPIPL value with saved protection level to see if it is higher than the saved value
rc_CPIP_B_ _INV req/ind
with basic call r2_SETUP resp/conf
Yes
No
Yes
No
Store CPIPL
CPIP Idle
rb_CPIP_B_ _INV req/ind
CPIP Idle
F ig u r e 2 2 - S S - C P I P , S D L f o r F E4
942, rc, FE5
942, rb, FE2/3
- 43 -
9.4.5
Be h a v io u r o f F E5 Figure 23 shows the normal behaviour of FE5. Input symbols from the right represent primitives from the called user. Output symbols to the left represent information flows to FE4.
Process CPIP_FE5
1(1)
CPIP Idle
Priority protection request
with basic call r2_SETUP resp/conf
rc_CPIP_B_ _INV req/ind
as part of response to initial call setup
951, rc, FE4
CPIP Idle
F ig u r e 2 3 - S S - C P I P , S D L f o r F E5
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9.5
Allocation of Functional Entities to physical equipment Table 11 shows the allocation of Functional Entities to physical equipment. In this table, TE indicates a TE attached to a PISN. Where a terminal involved is stimulus with respect to SS-CPIP, any TE shown as residing in the corresponding user’s TE, shall reside instead in that user’s PINX. T a b l e 1 1 - S c e n a r i o s f o r t h e a l l o c a t io n o f F E s t o p h y s i c a l e q u i p m e n t
9.6
Scenario
FE1
FE2
FE3
FE4
FE5
1
Calling user TE
Calling user PINX
Transit PINX
Called user PINX
Called user TE
Interworking considerations SS-CPIP applies only to portions of a call that lie within the PISN. For calls to and from other networks the Functional Entities are allocated to physical equipment as shown in table 12.
T a b l e 1 2 - S c e n a r i o s f o r t h e a l l o c a t i o n o f F Es t o p h y s i c a l e q u i p m e n t f o r n o r m a l o p e r a t i o n in c a s e o f in t e r wo r k in g wit h a n o t h e r n e t wo r k Scenario
FE1
FE2
FE3
FE4
FE5
2
Other network
Incoming Gateway PINX
Transit PINX
Called user's PINX
Called user's TE
3
Calling user TE
Calling user PINX
Transit PINX
Outgoing Gateway PINX
Other network
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