Implement SCCP connection coupling ("proxy")
If one wants to establish SCCP connections beyond the MTP label routing, the STP needs to perform "Connection Coupling"
This is basically more or less like a proxy for connections. It is needed as after SCCP connection establishment, the messages only contain the connection reference but no SCCP Called or Calling Party Address. Therefore, the messages can only be routed via MTP label, and the MTP-receiver must know the connection state.
AFAICT, this is not needed for connectionless SCCP (unit-data).
As CO-SCCP is only used on A and Iu, inside a single operator network, we can safely assume that we won't need connection coupling. A network inside an operator should be small enough that all nodes can be directly adressed by MTP point codes, without the use of GT based routing.