I'd like to update my microcontroler firmware via GPRS. I've an external I2C memory. My GSM modem has already an IP stack. I just need to transfer some bytes on the GSM UART and it arrives on the server side. No matter about TCP/IP.
The problem for me is GPRS technology and the protocol to implement between the microcontroler and the server.
Is it better to transfer 100 bytes packets or 1500 ? consider that sometimes the GPRS quality could be poor.
MTU (max transmit unit) =1500 bytes on this modem.
When the server transfer the 1500bytes to my microcontroler, would you add an ACK ? then send a new 1500Bytes frames ?
Would you add CTS/RTS hardware flow control ?
Would you add some CRC, checksum to check the integrity ?
Zmodem ? encryption needed ? compression is a plus ?
I'd like to have a standard protocol and not doing my protocol.
Anyone implemented a binary difference patch on 8bit microcontroler ? the lower data, the less GPRS cost.