charmhe / myProtocol

My own reliable data transfer protocol, implemented with TCP and UDP

TCP/IP stimulator

Intro: theory

(S = sender, R = receiver)

Base case:

S: sent

R: got

Advanced Case: with illegal msg

S: blabla

R: What? - Use the checksum to find the illegal of msg and set ACK = 1(acknowledgement) then send back

S: send again, with SEQ = bit changed (sequence number)

R: return

Advanced Case 2: with pkg lost

S: blabla

S: No response? Resend

Data structure

• ACK – Indicates if packet is ACK or not. Valid values (1 or 0)
• SEQ – Sequence number of packet. Valid values (1 or 0)
• DATA – Application Data (8 bytes)
• CHKSUM – MD5 Checksum of packet (32 Bytes)

You will need to create the packet, load it with the necessary values and then send it to the server.

This process will exactly mirror rdt 3.0 as shown in the textbook, so please make sure you follow it carefully!

How to do with cooruption functions

Please see UDP_Server.py, line 111