NetIF_MTU_Set() requires three arguments. The first function argument is the interface number of the interface to set the specified MTU. The second argument is the desired MTU to set, and the third argument is a pointer to a NET_ERR variable that will contain the return error code. The interface number is acquired upon the successful addition of the interface, and upon the successful return of the function, the return error variable will contain the value NET_IF_ERR_NONE and the specified MTU will be set.