Upstream Message Payload (Device to Application)
Devices can be setup to use private and or shared SAPs in one or more regions simultaneously. The messages from device are directly sent to the customer upstream application (if messaging endpoint configured) from the region in use by the device.
Devices can at any time make use SimplyTiny to request the list of available SAPs. If the provide_global_sap_list parameter is set to true in the device service template, the full list of private/shared SAPS from all regions will be sent to the device when device performs a SAP list request otherwise only the SAP of the current region is returned. The SAP list can be further controled by using the service template “service_access_point_permitted” parameter to restrict the SAP device may connect to and the restricted list to evaluate when returning the global sap list or regional sap list.
Downstream Message Payload (Application to Device)
For downlink messages your upstream application may use the API-Gateway of the region the device is connecting from or the API-Gateway of alternate with the API-Gw in other region for geo-resilience.To keep traffic local to a region/country it is recommended the IoT devices make use of the SAPs hosted in its current region and for the upstream application to make use of the API-Gateways in the device current region when sending messages to the device.