Company has done before single-chip computer connected to the Internet to send and receive data, using the STM32F103 + 4 g netcom module implementation, all through the module with the AT command to network and Socket connection, data transmission and communication, the customer now for data security, demanding VPDN access, the Internet has examined the related introduction, if VPDN access, you need to use L2TP protocol implementation link establishment, if they are under Linux, have ready-made protocol can be used, but taking into account cost factors, companies do not want on the system, and to use the existing platform implementation, I don't know whether it is feasible? Have ready-made library can refer to?
In addition if need to develop their own, without using the operating system, to realize this function, need to develop what the agreement? I checked L2TP protocol based on UDP implementation, is the need to implement TCP/IP, PPP these agreements? Thank you very much!

CodePudding user response:

SCM through 4 g module can even VPDN? Want to discuss,