TABLE OF CONTENTS In Figure 5.1 in Chapter 5, GSM A is sending an SMS to the subscriber +261323451234 of GSM B. GSM B wants to receive the SMS, but with the sending SMSC address of C (the SMS interworking network), which will be the proxy for the reception of all SMS-MT sent by GSM B's roaming partners as well as nonpartners:
B and C have an agreement (and an SCCP connection).
B and A have a roaming agreement.
C and A do not necessarily have an agreement.
B and C (for simplification of the explanation) have the same supplier for their international SCCP service. This supplier provides the basic service of translating to GSM B's HLRs addresses the "Called Party Addresses = MSISDN" used in the MAP_SEND ROUTING_INFO. In that case (if the GSM agrees), the translation table will point to a virtual HLR/MSC address that belongs to GSM B, but physically corresponds to equipment belonging to A.
Because voice roaming deals only with SCCP addresses that are individual network elements (HLR, VLR, MSC, SMSC), it is not impacted at all. The oriented graph model representation of Figure 16.2 corresponds to our problem:
Design the solution when third-party SMS interworking network C and GSM B do not have the same IGP supplier.
Is there a (theoretical) way that the CNF from C (the SMS interworking network in Figure 16.2) goes back to A through B? Could your international carrier SCCP gateways do it?
In the setup of Figure 16.2,...
