our current network provider says that they have a restriction on their sim profile so that the mtu should be less than 1430. however things like pdn_dynamic_params_get() and at+cgcontrdp report differently (1500).
however, when we make a tcp connection (w/ tls) we see the tcp max-segment-size option set w/ 708. my reading of this option means that the modem's networking should restrict things so that it could have data outstanding but it's going to be restricted so that it doesnt get out of hand. the interfaces to the network stack dont allow for querying this (eg, getsockopt()) so asking how this value is getting set?