














                              - 2 -
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                Contents of Recommendation Q.85                                 
         COMMUNITY OF INTEREST SUPPLEMENTARY SERVICES 
1.   Closed user group

2.   ISDN networking (under study)

3.   Private numbering plan (under study)


                               *
                                
                            *     *
                                
                                


Recommendation Q.85


          COMMUNITY OF INTEREST SUPPLEMENTARY SERVICES

1.     Closed user group

1.1    Introduction

       The supplementary service closed user group (CUG) makes provision  for  a
group of  users  to  meet  security  requirements  of  certain  applications  by
providing restrictions, which prevent non-members from reaching these applications.

       The  basic  facility  provides,  via  the  ISDN,  the  CUG  members  with
controlled intercommunication exclusively amongst themselves and denies access into or 
outside the group. This facility can be extended to include outgoing and/or incoming 
access for specified CUG members.

1.2    Definition of functional model

1.2.1  Functional model description

       The high  level  functional  model  for  the  CUG  service  contains  the
following network addressable functional entities:




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                                FIGURE 1-1/Q.85
                                        
                          CUG service functional model


       FE 1: originating CUG agent
       FE 2: outgoing CUG determination
       FE 3: outgoing CUG control
       FE 4: incoming CUG determination
       FE 5: incoming CUG control
       FE 6: destination CUG agent

1.2.2.1     Outgoing CUG determination entity (FE 2)

       It has the ability:

       -    to identify a CUG call;

       -    to check the CUG subscription of the calling user;

       -    to access the outgoing CUG control entity

1.2.2.2     Outgoing CUG control entity (FE 3)

       It performs:

       -    the validation checks of CUG information of a calling user;

       -    the conversion of the CUG index to an interlock code.

1.2.2.3     Incoming CUG determination entity (FE 4)

       It has the ability:

       -    to identify a CUG call;

       -    to check the CUG subscription of the called user;

       -    to access the incoming CUG control entity.








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1.2.2.4     Incoming CUG control entity (FE 5)

       It performs:

       -    the conversion of the interlock code to CUG index;

       -    the validation checks of CUG information of a  called  user
            (including  the  compatibility   with   the   called   user
            class - CUG IA - in case of an ordinary incoming call).

Note - FE 3 and FE 5 are coupled in the sense that they handle a common  set  of
data (interlock codes).

1.2.3  Relationship to basic service

       Refer to  1.6 for the physical location of each entity residing  in  the
following figure.


















                                        
                                        
                                        
                                FIGURE 1-2/Q.85
                                        
                      Relationship to basic service model
                         First case: type A of scenario





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                           AP IX-99-E
                                

1.3.   Information flow description

1.3.1  Information flow diagrams









































Note 1 - This information flow may be omitted.

                                        
                                FIGURE 1-3/Q.85
                                        
                              Successful CUG calls
                                        





















                              - 6 -
                           AP IX-99-E
                                














                                FIGURE 1-4/Q.85
                                        
                        Unsuccessful CUG calls - Case 1

























                                FIGURE 1-5/Q.85
                                        
                        Unsuccessful CUG calls - Case 2



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1.3.2  Definition of individual information flows

       The  parameters  that  are  carried  on  the  information  flows  in  the
successful case are as follows:

1.3.2.1     SETUP (FE 1 - FE 2) - in addition to called party number and CLI

       -    nothing, or

       -    index, or

       -    index + OA indication.

1.3.2.2     ENQUIRY (FE 2 - FE 3) - carries the same information as SETUP  (FE  1  -
FE 2) except called party number.

1.3.2.3     ENQUIRY (FE 3 - FE 2):

       -    nothing, or

       -    interlock code, or

       -    interlock code + OA indication.

1.3.2.4     SETUP (FE 2 - FE 4) - in addition to called party number

       -    nothing, or

       -    interlock code, or

       -    interlock code + OA indication.

1.3.2.5     ENQUIRY (FE 4 - FE 5) - carries exactly the same information  as  SETUP
(FE 2 - FE 4).

1.3.2.6     ENQUIRY (FE 5 - FE 6):

       -    nothing, or

       -    index, or

       -    index + OA indication.

1.4.   Functional entity actions








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       FE 1 - A user initiates call SETUP request with the CUG  index  code
(when a preferential CUG is used, no index code is designated).

       FE 2 - identify a CUG call and receive CUG information,

            - CUG subscription check of the calling user.

       FE 3 - Outgoing validation check:

            1)   CUG index code check of a calling user (when no  index  code
                 is designated, preferential CUG is used);

            2)   outgoing barring check within CUG;

            When any logical contradiction is detected in  the  above
            procedure, a call is rejected (see Table 1-1/Q.85).

           - conversion of the index code to an interlock code.

       FE 4 - identify an incoming CUG call and receive CUG information;

            - CUG subscription check of the called user.

       FE 5 - incoming validation check:

            1)   incoming barring check within CUG;

            2)   if interlock codes do not match between a calling  user  and
                 a called user, a call is rejected;

            3)   ordinary incoming call check (CUG IA);

            When any logical contradiction is detected in  the  above
            procedure, a call is rejected (see Table 1-2/Q.85).

           - an index code corresponding to the designated interlock code is
            extracted from CUG data of a called user.

       FE 6 - a user checks whether or not the designated index code  exists  in
       the  index  code  list  of  his   own.   A   user   shall   give   proper
       responses.




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1.5.   SDL diagrams for functional entities

1.5.1  FE 1 originating CUG agent

       FE 1 has the same SDL diagram as the CCA FE (basic call)  except  that
the SETUP information flow to the FE  2  must  carry  additional  information
(index or index + OA or nothing).









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1.5.2  FE 2 outgoing CUG determination
         
       Refer to the following figure
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                              FIGURE 1-6/Q.85
                                      
                            SDL diagram for FE 2




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1.5.3  FE 3 outgoing CUG control
         
       Refer to the following figure
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                                      
                              FIGURE 1-7/Q.85

                                   FE 3 








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                               TABLE 1-1/Q.85
                                      
                  CUG interpretation table (outgoing side)

   кФФФФФФФФФФФФФФФФФФТФФФФФФФФФФТФФФФФФФФФФФТФФФФФФФФФФФТФФФФФФФФФФФФФП
   Г            SETUP ГCUG with  Г CUG with  ГCUG withoutГNo. CUG INFO.Г
   Г           presen-Гindex     Г index     Гindex      Г             Г
   ГCalling    tation Г          Г           Г           ГOrdinary     Г
   Гuser class        ГOA=OFF    Г OA=ON     ГOA=ON      Гsubscriber   Г
   УФФФТФФФФТФФФФТФФФФД          Г           Г           Г             Г
   Г   ГCUG+ГCUG+Г    Г          Г           Г           Г             Г
   ГCUGГ OA Г OA ГpCUGГ          Г           Г           Г             Г
   Г   Г(E) Г(I) Г    Г          Г           Г           Г             Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г Y Г    Г    Г    ГSpecified Г Specified Г Rejected  Г Rejected    Г
   Г   Г    Г    Г    ГCUG     *1Г CUG     *1Г           Г             Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г   Г Y  Г    Г    ГSpecified Г Specified Г Ordinary  Г Rejected    Г
   Г   Г    Г    Г    ГCUG       Г CUG with  Г call      Г             Г
   Г   Г    Г    Г    Г        *1Г OA      *2Г           Г             Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г   Г    Г Y  Г    ГSpecified Г Specified Г Ordinary  Г Ordinary    Г
   Г   Г    Г    Г    ГCUG with  Г CUG with  Г call      Г call        Г
   Г   Г    Г    Г    ГOA      *1Г OA      *2Г           Г             Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г Y Г    Г    Г Y  ГSpecified Г Specified Г pCUG      Г pCUG        Г  FE 3
   Г   Г    Г    Г    ГCUG     *1Г CUG     *1Г         *1Г           *1Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г   Г Y  Г    Г Y  ГSpecified Г Specified Г pCUG with Г pCUG        Г
   Г   Г    Г    Г    ГCUG       Г CUG with  Г OA        Г             Г
   Г   Г    Г    Г    Г        *1Г OA      *2Г         *2Г           *2Г
   УФФФХФФФФХФФФФХФФФФХФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФХФФФФФФФФФФФФФД
   Г   Г    Г Y  Г Y  ГSpecified Г Specified Г pCUG with Г pCUG with   Г
   Г   Г    Г    Г    ГCUG with  Г CUG with  Г OA        Г OA          Г
   Г   Г    Г    Г    ГOA      *1Г OA      *1Г         *1Г           *2Г
   РФФФСФФФФСФФФФСФФФФСФФФФФФФФФФСФФФФФФФФФФФСФФФФФФФФФФФСФФФФФФФФФФФФФй
   .   .    .    .    .          .           .           .             .
   .   .    .    .    .          .           .           .             .
   .   .    .    .    .          .           .           .             .
   кФФФФФФФФФФФФФФФФФФТФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФТФФФФФФФФФФФФФП
   Г Calling user is  Г           REJECT                 Г  Ordinary   Г
   Г    NOT CUG       Г                                  Г    call     Г  FE 2
   РФФФФФФФФФФФФФФФФФФСФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФСФФФФФФФФФФФФФй

*1     :    In case of OCB (CUG), a call is rejected
*2     : In case of OCB (CUG), a call is interpreted as an ordinary call
OA(E)  :    Outgoing access explicit
OA(I)  :    Outgoing access implicit
OA     :    Outgoing access allowed
OCB    :    Outgoing access barred within the CUG
pCUG   :    Preferential call
Y      :    Yes
Note 1 -    When an illegal index code is received, the outgoing call is rejected.
Note 2 -    All the user classes are not necessarily supported by all  the  networks.
       User classes to be supported are network dependent.




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                           AP IX-99-E
                                
1.5.4  FE 4 incoming CUG determination
         
       Refer to the following figure














































                              FIGURE 1-8/Q.85 (1 of 2)
                                          
                                        FE 4









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                             FIGURE 1-8/Q.85 (2 of 2) 
                                          
                                       FE 4 



                              - 15 -
                           AP IX-99-E
                                

1.5.5       FE 5 incoming CUG control
      
       Refer to the following figure














































                                  FIGURE 1-9/Q.85 

                                       FE 3 








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                           AP IX-99-E
                                

                                   TABLE 1-2/Q.85
                                          
                           CUG checking in incoming side

          кФФФФФФФФФФФФФФФФФТФФФФФФФФФФФФФФФФФФФФФФФФФФФФФФТФФФФФФФФФФФФФП
          Г           CalledГ     Called user is CUG       Г Called user Г
          Г           user'sУФФФФФФФФФФФФФТФФФФФФФФФФФФФФФФД is not CUG  Г
          Г           class ГCUG with or  Г CUG IA with or Г             Г
          Г                 Гwithout pCUG Г without pCUG   Г             Г
          ГSETUP            УФФФФФФФТФФФФФХФФФФФФФФФТФФФФФФД             Г
          Гpresentation     ГNo ICB Г ICB Г  No ICB Г ICB  Г             Г
          УФФФФФФФФФФФФФФФФФХФФФФФФФХФФФФФХФФФФФФФФФХФФФФФФХФФФФФФФФФФФФФД
          Г                 ГM (1)  Г     Г  M (1)  Г      Г             Г
          ГCUG              УФФФФФФФД REJ УФФФФФФФФФД REJ  Г     REJ     Г
          Г                 ГNM REJ Г     Г  NM REJ Г      Г             Г
          УФФФФФФФФФФФФФФФФФХФФФФФФФХФФФФФХФФФФФФФФФХФФФФФФХФФФФФФФФФФФФФД
          Г                 ГM (1)  Г     Г  M (2)  Г      Г             Г
          ГCUG and OA       УФФФФФФФД REJ УФФФФФФФФФД (3)  Г     (3)     Г
          Г                 ГNM REJ Г     Г  NM (3) Г      Г             Г
          УФФФФФФФФФФФФФФФФФХФФФФФФФХФФФФФХФФФФФФФФФХФФФФФФХФФФФФФФФФФФФФД
          ГOrdinary         Г REJ   Г REJ Г   (3)   Г (3)  Г   (3)   *   Г
          РФФФФФФФФФФФФФФФФФСФФФФФФФСФФФФФСФФФФФФФФФСФФФФФФСФФФФФФФФФФФФФй

ICB: Incoming access barred within the CUG

Note - Since CUG OA user class is not concerned in the incoming case, it is not shown 
in the above list. It shall be regarded that CUG OA user class is the  same  as  user
class CUG, and CUG OA/IA is the same as user class CUG IA in this table.

     - Most of the table is performed in FE 5.

Notes to the TABLE 1-2/Q.85

Note 1 -    (1)-(3) shows CUG parameter to be used in the SETUP to the called user.
       (1) - CUG (index)
       (2) - CUG + OA (index + OA mark)
       (3) - No CUG (ordinary call)

Note 2 - ICB means incoming calls barred within the CUG.  The  interpretation
logic is changed in this case as shown in  each  column  in  the  table.  For
example:

                              кФФФФФФФТФФФФФП
                              ГNo ICB Г ICB Г
                              УФФФФФФФХФФФФФД
                              ГM (1)  Г REJ Г
                              РФФФФФФФСФФФФФй

       This means that when the interlock codes are matched  and  no  ICB  is
applied for the CUG, then (1) is used. However, when ICB is applied for the CUG, 
the incoming call is rejected even if interlock codes are matched.

Note 3 - M means that the interlock code is matched with the CUG of  the  called
user.

Note 4 - NM means "not matched".

Note 5 - REJ means that an incoming call is rejected.

Note 6 - Interpretation logic, e.g.:
                                     к   ФП
                                     Г M  Г
                                     Г(3) Г
                                     Р   Фй



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                           AP IX-99-E
                                
means that when matched with CUG, no CUG selection facility field is set in  the
SETUP to the called user.

1.5.6 FE 6 destination in CUG agent

       FE 6 has the same SDL diagram as the CCA FE (basic call) except that  the
SETUP information flow to the FE 6 must carry additional information  (index  or
index + OA mark or nothing).

1.5.7 Basic call hooks
                                             See the following two diagrams.  








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                           FIGURE 1-10/Q.85 (1 of 5)
                                        
                     C C Functional Entity (r1-ri) i = 1,2(based on Recommendation Q.71)  



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                           FIGURE 1-10/Q.85 (2 of 5)
                                        
                     C C Functional Entity (r1-ri) i = 1,2
                        (based on Recommendation Q.71)  








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                           FIGURE 1-10/Q.85 (3 of 5)
                                        
                     C C Functional Entity (r1-ri) i = 1,2)
                        (based on Recommendation Q.71)                                  



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                           FIGURE 1-10/Q.85 (4 of 5)
                                        
                     C C Functional Entity (r2-ri) i = 1,2
                        (based on Recommendation Q.71)  
                                        








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                           AP IX-99-E
                                
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                                        
                           FIGURE 1-10/Q.85 (5 of 5)
                                        
                     C C Functional Entity (r2-ri) i = 1,2(based on Recommendation Q.71)                                   



                              - 23 -
                           AP IX-99-E
                                

1.6    Network physical allocation scenarios

                                 TABLE 1-3/Q.85
                                        
                    Network physical allocation scenario A 
       кФФФФТФФФФФФФФТФФФФФФФФФТФФФФФФФФФТФФФФФФФФФТФФФФФФФФФТФФФФФФФФФП
       Г    Г        Г         Г         Г         Г         Г         Г
       Г    Г  FE 1  Г  FE 2   Г  FE 3   Г  FE 4   Г  FE 5   Г  FE 6   Г
       УФФФФХФФФФФФФФХФФФФФФФФФХФФФФФФФФФХФФФФФФФФФХФФФФФФФФФХФФФФФФФФФД
       ГA.1 Г TE/NT2 Г   LE1   Г   LE1   Г   LE2   Г   LE2   Г TE/NT2  Г
       ГA.2 Г TE/NT2 Г   LE1   Г   DB1   Г   LE2   Г   DB1   Г TE/NT2  Г
       ГA.3 Г TE/NT2 Г   LE1   Г   DB1   Г   LE2   Г   DB2   Г TE/NT2  Г
       ГA.4 Г   TE   Г  NT2A   Г  NT2A   Г  NT2A   Г  NT2B   Г   TE    Г
       РФФФФСФФФФФФФФСФФФФФФФФФСФФФФФФФФФСФФФФФФФФФСФФФФФФФФФСФФФФФФФФФй
       The network scenario A.1 represents the decentralized approach of the CUG 
service implementation.

       The network scenario A.2 describes the fully centralized approach with  a
unique data base (DB1).

       The network scenario A.3 describes a centralized approach with  two  data
bases (DB1 and DB2).

       In the network scenario A.4, the Cug service is handled in the  NT2s  and
then the network is transparent for this service.