CAP1 Reorigination Process

Call Control Framework (CCF) can process CAP1 mobile originating (MO) calls using the TSAN reorigination service.

When a roaming subscriber makes an MO call through a Visitor Mobile Switch Center (VMSC) that can process calls using only CAP1, the CCF TSAN reorigination service processes the call as follows:
  1. The VMSC sends a CAP1 InitialDP message for the call to MATRIXX Engine, through Network Enabler. The InitialDP has the calling destination (Cd) and called party (Cp) numbers.
  2. Based on the service key for the call, the Charging Server decides to treat the call as a reoriginated call. The TSAN reorigination service:
    • Looks for a free TSAN (one that is in an inactive state) in the MATRIXX database.
    • Sets the TSAN to active.
    • Stores a copy of parameters from the InitialDP, such as the Cd and Cp numbers, to the MtxIDPParameters MDC.
  3. The TSAN reorigination service returns a TCAP (Connect) message, containing the TSAN in the DRA field, to the VMSC and starts the TSAN timer. After receiving the TSAN, the VMSC sends an ISUP IAM (ISDN user part initial address message) containing the TSAN to the home GMSC.
    Note: The GMSC is capable of processing calls using CAP2, CAP3, or CAP4. The VMSC can connect to the GMSC because the TSAN is a routable number.
  4. The GMSC sends a new InitialDP to Network Enabler using CAP2, CAP3, or CAP4. The new InitialDP includes the TSAN in the Cd field, and the Cp from the original InitialDP.
  5. After receiving the new InitialDP, Network Enabler looks up the Cd number in its TSAN Route Cache so that it can forward the InitialDP to the correct MATRIXX sub-domain. CCF selects a voice charging service based on the service key in the new InitialDP. The voice charging service:
    • Compares the Cd with the active TSANs in the MATRIXX database in the sub-domain. If the voice charging service finds a match, it uses the parameter values copied to the MtxIDPParameters MDC (such as the original calling and called party numbers), and the current IDP, to process the call as a standard CAP2, CAP3, or CAP4 call.
    • Cancels the TSAN timer.
    • Sets the TSAN to an inactive state, so that CCF can reuse it for another CAP1 call.
Figure 1 shows the reorigination process for a CAP1 call:
Figure 1. TSAN Reorigination Process