Internet Standards/CD2.mdf/ccitt/1992/q/q82.asc

Text File | 1991-12-31 | 15KB | 485 lines

               Contents of Recommendation Q.82

              Call offering supplementary services

                                                                           Page

1.   Call transfer (under study) ..........................................  6

2.   Call forwarding services .............................................  6

3.   Call deflection (under study) ........................................ 29

4.   Line hunting ......................................................... 29


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Recommendation Q.82

                      CALL OFFERING SUPPLEMENTARY SERVICES

1.     Call transfer

       Under study.

2.     Call forwarding services

2.1    Introduction

2.1.1  General

       This Recommendation includes Stage 2 descriptions for  the  three
versions of Call Forwarding Services given below, when implemented using
the  "forward  switching"  network  routing   algorithm   described   in
Recommendation Q.80.
       The following descriptions are for further study:

       -    re-routing case as described in Recommendation Q.80;

       -    the optional notification to be sent to the calling user  A  when
            the   value   of   the   subscription   option   "calling    user
            receives  notification  that  his  call   has   been   forwarded"
            is "yes, with forwarded-to-user number";

       -    the optional notification to be sent to the served user  Bm  when
                           the   value    of    the    subscription    option
            "served   user   receives   notifcation   that   his   call   has
            been forwarded" is "yes, with call offering information".

       Further details and definitions of the Stage 1 description,  i.e.,  the
service   description   as   seen   from   the   user,   can   be   found   in
Recommendation I.252.

2.1.2  Definitions

Call Forwarding Unconditional (CFU)












       Call Forwarding Unconditional (CFU) permits a user to have the  network
send all incoming calls, or just those associated with a specific basic
service, addressed to the served user's ISDN number to another number. The served user's
originating service is  unaffected.  If  this  service  is  activated,  calls  are
forwarded no matter what the condition of the termination. Other call forwarding services
provide call forwarding based on condition e.g. Call Forwarding Busy (CFB) and Call
Forwarding No Reply (CFNR).

Call Forwarding Busy (CFB)

       Call Forwarding Busy (CFB) permits a served user to have the  network  send
all incoming calls, or just those associated with a specific basic service,  which
meet Busy and are addressed to the served user's ISDN number to another number. The
served user's originating service is unaffected.

Call Forwarding No Reply (CFNR)

       Call Forwarding No Reply (CFNR) permits a served user to have  the  network
send all incoming calls, or just those associated with a specific  basic  service,
which meet No Reply and are addressed to the served user's ISDN number to  another
number. The served user's originating service is unaffected.

2.     Call forwarding setup and release


2.2.1  Information flow diagrams

       Call Forwarding Unconditional and for "network determined  user  busy":
       Figure 2-2/Q.82.

       Call Forwarding for "user determined user busy": Figure 2-3/Q.82.

       Call Forwarding on no reply: Figure 2-4/Q.82.

       Call Forwarding disconnect procedure (including Advice  of  Charge):
       Figure 2-5/Q.82.




Notes related to Figures 2-2 to 2-4/Q.82.

Note 1 - The calling party number and the last forwarding number  should  be
included if required  by  the  "calling  line  identification  presentation"
supplementary service.

Note 2 - The Notification should be sent only if the B-party subscribes  to  the
"calling  User  Receives  Notification  that  his  call  has   been   forwarded"
subscription  option.

Note 3 - The connected number is included if required  by  the  "Connected  Line
Identification Presentation/Restriction" supplementary service.

Note 4 - The forwarded-to-user will receive this information  depending  on  his
notification option, the availability of this information from the  network  and
possible presentation restrictions.

Note 5 - This parameter may be omitted between FE4 and FE6 in order to limit the
number of parameters to be passed in the network (see Table 2-6/Q.82 note 1).








2.2.4  Definition of individual information flows

       Refer to information indicated in the notes related to Figures 2-2 to 2-5/Q.82 and  2.2.5.


2.2.5  Multiple diversion address handling

                                FIGURE 2-7/Q.82
                                 TABLE 2-1/Q.82

                    Information carried in the SETUP req.ind
Note 1 - May be omitted to limit the number of parameters being  passed  in  the
network.

Note 2 - V(B1) indicates the reason for diversion from party B1 with  a  value  (V)
equal to:  unknown/not  available,  user  busy,  no  reply  or  unconditional  when
diversion occurs.



                                  TABLE 2-2/Q.82

                      Information in the backwards direction












2.2.6  Functional Entity Actions

       1)   Functional Entity Actions for FE1

            -    Receive indications relating to the service from FE2

       2)   Functional Entity Actions for FE2

            -    Receive indications relating to the service from  FE4  and
                 forward them to FE1

       3)   Functional Entity Actions for FE3

            -    No Functional Entity Actions uniquely relating  to  this
                 service are identified for FE3

       4)   Functional Entity Actions for FE4/FE6

            -    Store call information and user's service  allocation  and
                 state

            -    Run periodic timers specific to the service

            -    Stimulate forward basic call setups to  nominated  numbers
                 when service is active

            -    Increment service call counts and forward to next FE4/6

            -    Stimulate release procedures at service call count limit

            -    Receive and implement user's service requests from FE5/7

            -    Determine information to be notified backwards  to  other
                 users

       5)   Functional Entity Actions for FE5/FE7

            -    Receive indications relating to the service from FE4/6

            -    Receive and forward user's service requests to FE4/5

       6)   Functional Entity Actions for FE8

            -    Receive and increment forward call counter
                 (Note - This is an attribute of FE4/6.)







            -    Send forwarding indicators relating to the service  of  FE9
                 (This would be an attribute to FE6.)

       7)   Functional Entity Actions for FE9

-    Receive indications relating to the service from FE8












2.3    Possible allocation of Functional Entities to physical locations


             │  A PARTY ■│     │  B1 PARTY ■│  Bx PARTY ■│  C PARTY ■
             │ FE1 │ FE2 │ FE3 │  FE4 │ FE5 │  FE6 │ FE7 │  FE8 │ FE9
─────────────┼─────┼─────┼─────┼──────┼─────┼──────┼─────┼──────┼─────
  Scenario 1 │ TE  │ LE  │ TR  │  LE  │ TE  │  LE  │  TE  │   LE   │  TE
─────────────┴─────┴─────┴─────┴──────┴─────┴──────┴─────┴──────┴─────

       Other scenarios are for further study.

2.4    Interactions with other supplementary services

       The interaction with supplementary services, such as calling line
identification, connect-test line identification and  advice  of  charge
have been considered; interactions with other supplementary services are for
further study.

2.5    Terminology and abbreviations

Abbreviations used:

       CFU  Call Forwarding Unconditional
       CFB  Call Forwarding on Busy
       CFNR      Call Forwarding on No Reply
       CD   Call Deflection
       CC   Call Control
       CCA  Call Control Agent
       FE   Functional Entity
       TE   Terminal Equipment
       LE   Local Exchange
       TR   Transit Exchange
       NDUB      Network Determined User Busy
       UDUB      User Determined User Busy

Terminology:

       Original Called Number

            The number of originating party dials

       Connected Line Number

            The number of the final destination

       Forwarding Number

            The number of the served user, i.e. the subscriber  who  initiates
            the   Forwarding   service   and   from   where   the   call   has
            been forwarded

       Forwarded-to-number

            The number to which a call has been forwarded







       Forwarding indicator

            Indicator showing that call has been forwarded  and  indicating
            whether  or  not  this   information   should   be   given   to
            calling party

3.     Call deflection

       Under study

4.     Line hunting

4.1    Introduction

4.1.1  Definition

       Line hunting is a supplementary service which enables incoming  calls  to
a specific ISDN number to be distributed over a group of interfaces.

Note - Expansion of the line hunting service to cover the  case  of  hunting  on
available ISDN numbers or addresses, rather than on  interfaces  is  a  possible
extension of the service.

4.1.2  Description

       This description covers  the  form  of  line  hunting  which  applies  to
interfaces within one node. It is an anticipated further extension to enable the group
of interfaces available for selection to be distributed over more than one node.

       The selection of an interface within a node is performed on the basis  of
the hunting algorithm used. (Where hunting is extended over more than  one  node
the network routing techniques used to extend the selection to the next node may be
similar to that used for  the  call  forwarding  supplementary  service,  though
applied by the administration. The precise description of multi-node Line Hunting is
for further study.)

       An access belonging to a line hunting group may also be  addressed  using
an individual ISDN number. Facilities assosciated with the individual number are
not affected by line hunting.

4.2    Definition of the functional model

       The additional functionality required for line hunting, over that of  the
basic service, is confined to a single node, as seen in Figure 4-1/Q.82.

4.3    Information flow

4.3.1  Flow for single node hunting

       For the single node case the information flows are those defined for  the
basic call as shown in Figure 6-2/Q.82. No information flows arise as a result of
the hunting action.












4.3.2  Flow for multi-node hunting

       This is for further study.

4.     SDL diagrams

       The SDL diagrams for the entity FE1 are  shown  in  Figure  4-3/Q.82  and
Figure 4-4/Q.82.
                                FIGURE 4-1/Q.82

                 Relationship of line hunting to basic service

                          (Continue as per Basic Call)

Note 1 - Only those entities directly involved in line hunting are shown.

Note 2 - The selected access may be to a CC or a CCA.

                                FIGURE 4-2/Q.82

                       Information flows for line hunting








Note 3 - This SDL is executed within the "Term. Screen. Process Attempt" process
boxes at reference points 241, 241A in the basic call SDL.

                                FIGURE 4-3/Q.82

                             SDL1 for line hunting












                                FIGURE 4-4/Q.82

                             SDL2 for line hunting






4.5    Functional Entity Actions

4.5.1  Single node hunting

       The FEAs attributed to entity FE1, the Line Hunting entity, indicated  by
(1) on the information flow diagram are as follows:

       -    determine hunting algorithm;

       -    select free interface.

4.5.2  Multi-node line hunting

       FEAs, in addition to the single node FEAs, which are required for hunting
over more than one node are for further study.

4.6    Physical locations for functional entities

       The scenarios which apply to line hunting are shown in
Table 4-1/Q.82.

                                 TABLE 4-1/Q.82

                        Possible line hunting scenarios

┌────────────────┬─────────┬─────────┬─────────┬────────┬─────────┬─────────┐
│     Functional │         │         │         │        │         │         │
│        Entities│   CCA   │   CC    │   CC    │ CC/FE1 │   CC    │   CCA   │
│                │         │         │         │        │         │         │
│Scenario        │         │         │         │        │         │         │
├────────────────┼─────────┼─────────┼─────────┼────────┼─────────┼─────────┤
│1) Basic rate   │   TE    │   LE    │   TR    │   LE   │    -    │   TE    │
│   access       │         │         │         │        │         │         │
├────────────────┼─────────┼─────────┼─────────┼────────┼─────────┼─────────┤
│2) Basic rate   │   TE    │   LE    │   TR    │   NT2  │    -    │   TE    │
│   access       │         │         │         │        │         │         │
├────────────────┼─────────┼─────────┼─────────┼────────┼─────────┼─────────┤
│3) Primary rate │   TE    │   LE    │   TR    │   LE   │   NT2   │   TE    │
│   access       │         │         │         │        │         │         │
└────────────────┴─────────┴─────────┴─────────┴────────┴─────────┴─────────┘


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