In summary:
Type B Costs can be high, but for certain types of Operational Message the Store and Forward, automatic re-routing and
guaranteed delivery, means that Type B is the safe option.
Long Answer
:
Having said that an OCC with a modern suite of Systems can mitigate Type B Costs by using a routing table so that Internal addressees receive MVT etc over an the LAN without going into the SITA Network. This, if the system is properly designed can also include certain external addresses using email (for instance Main Base Contractors, especially those with access to FIDS, or OCC System Displays).
Stepping up a level and assuming all the Airline Systems are sophisticated enough and there is a WAN to Outstations with network monitoring is in place, then the Outstation Systems can automatically transmit updates to local contractors/agents over their CUTE/CUSP/LAN.
This would mean in Normal Circumstances, Type B routing would only be required for Stations, or other Addressees outside the WAN/LAN coverage
(Using email can give them the 'We didn't get in time' excuse - A QU Priority over Type B doesn't).
But even then there should be exceptions DIV, or emergency Messages should for assurance use Type B as well as the standard message routing.
Also if the Networking Monitoring shows one, or stations off line, then routing to these locations should automatically fall back to Type B.
As Merlinxx says:
E-mail fine until someone pulls the net, go to GSM until they close the cell. SITA stable in unstable areas, yup maybe a financial burden, but geopolitical stable.
So no matter how sophisticated your messaging and systems are, Type B access provides the fall back and in some cases the only means of getting a message through in a timely manner.