.. nztim: change the APN to direct.telecom.co.nz = dynamic public ip and no CG-NAT...
Would assume they've not allowed that with these SIMs for FWA
Correct. It won't terminate on the correct network.
It's actually not provisioned to the device profile rather than won't terminate on the correct network as the only allowed APN on Wireless Broadband was "broadband". Plus you need to have the Huawei B315/618 IMEI range for the SIM to work as you can't move it from the Spark supplied device into your own device.
It was done so the rating and billing process can be done differently ie when you connect wireless broadband you get a larger data allocation before the core router needs to check back with the billing platform if they still have available data... Or that was how it was setup when I was at Spark. ;)
And for Static IP it is provisioned at the core so the end-user doesn't need to change their APN setting to be terminated onto the fixed broadband network over a L2TP tunnel rather than being routed via the mobile core and being behind the CGNAT gateway.