SMS Hubbing

The lack of complete international SMS coverage is caused by the way the mobile operartors are interconnected i.e., each operator establishes SMS connectivity with all other mobile operators, meaning that SMS could be send worldwide only  if sent from one operator to another if there is a bi-lateral roaming agreement in place.

While SMS interoperability is limited to bi-lateral interworking / roaming agreements between operators, it is unlikely that full international SMS coverage could be done by setting up more and more agreements, which consumes a lot of time and money. In addition the revenue benefits for setting up extra interworking connections may not work at first place.