Ah, thanks. I couldn't find the notes you mentioned (AN10, AN13 and AN14) there, but the documents on this page seem to describe the architecture and protocols you mention: http://iot.semtech.com/resources/Server_Release_2.1.1 (annoying that Semtech doesn't use the AN numbers in the links on that page :-S).
Quickly looking at that suggests that their Network Server corresponds to our Broker, their Application server is our handler and their customer server is our application server. In our architecture, we have inserted a router, because the gateway owners cannot be expected to forward data to all brokers, and application owners cannot be expected to trust all network servers with their network session keys.