ISO IEC 13865 pdf download – Information technology — Telecommunications and information exchange between systems — Private Integrated Services Network — Specification, functional model and information flows — Call Transfer supplementary service

ISO IEC 13865 pdf download – Information technology — Telecommunications and information exchange between systems — Private Integrated Services Network — Specification, functional model and information flows — Call Transfer supplementary service
7.3Functional Entity actions
The following FE actions shall occur at the points indicated in the figures of 7.2.3.7.3.1 Functional Entity actions of FE1
101 FEl shall detect the user request for transfer. Local checks on the suitability of the transfer may be made and the
request rejected on the basis of such checks. If the transfer is not barred locally, a Transfer Invoke request shall besent to FE2.
102
On receipt of the ‘Transfer Invoke confirmation, FEl shall inform the user of the result, and in the case of successfulcompletion, it may release the primary and secondary calls if they have not yet been released.
7.3.2 Functional Entity actions of FE2
201On receipt of a Transfer Invoke indication from FE1, FE2 shall identify the primary and secondary calls and check the
validity of the request from the network’s point of view. The transfer shall be deemed invalid if the primary andsecondary calls have incompatible bearer capabilities.
lf the transfer is found to be invalid, a Transfer Invoke response shall be sent to FE1 indicating rejection.
lf the transfer is deemed valid, a response indicating success shall be sent to FE1, the connections of the primary andsecondary calls towards User B and User C shall be joined together and the connections of the primary and secondarycalls towards User A shall be cleared. A Transfer Complete request shall be sent to each of the FE3s.
lf User C was not being alerted at the time of transfer, the two local CCs shall be merged to form a new Transit CC forthe new call.
202
lf User C was being alerted at the time of transfer, a Transfer Active request shal be sent to User B’s FE3 on detectionof answer by User C (indicated by the receipt of a basic call Setup confirmation by the basic call CC collocated withFE2).
The two local CCs shall be merged to form a new Transit CC for the new call.
7.3.3 Functional Entity actions of FE3
301 On receipt of a Transfer Complete indication from FE2, a Transfer Notify request shall be sent to the associated FE4,
a Transfer Update request shall be sent to the other FE3 and details relevant to the network concerning the new user inthe call may be stored. The Transfer Notify shall contain element Terminal Details Request unless it is sent to a UserC that has not answered.Any notifications appropriate due to other supplementary services may be sent to the newuser in the call.
302
On receipt of a Transfer Update indication from the other FE3, a ‘Transfer Notify request shall be sent to theassociated FE4 and details relevant to the network concerning the other user in the call may be stored.
303 On receipt of a Transfer Active indication from FE2, relevant details may be stored and a second Transfer Notify
request shall be sent to the associated FE4.
7.3.4Functional Entity actions of FE4
401 On receipt of a Transfer Notify indication from the associated FE3 or a Terminal Details indication from the other
FE4, relevant details may be stored. In the case of receipt of a Transfer Notify indication containing element TerminalDetails Request, a ‘Terminal Details request may be sent to the other FE4 if appropriate. In the case of an alertingtransfer, the FE4 associated with User B can receive two of either indication.
7.4Functional 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 cach FE is shown using the Specification and Description Language (SDL) defined in ITU-T Rec.Z.100.7.4.1 Behaviour of FE1
Figure 6 shows the normal behaviour of FE1.Input signals from the left and output signals to the left represent primitives fromand to User A. Input signals from the right and output signals to the right represent information flows from and to FE2.