NCP

The goal of the project is to implement a TCP-like protocol over an UDP socket

Tree hierarchy

• ./bin -> C executable, server and client
• ./src -> .c source files
• ./pres -> Our presentation slideshow
• ./files -> the files the server can acceed and distribute over the network.
• ./subject -> the project instructions and expectations .pdf
• ./obj -> .o C object files

How to use :

Files serve by the server MUST be located in the "files" directory.

How to write to file nicely

DO NOT use string specific fn because we gonna work on not string files !!

Use thing like

• int n = fread()
• int n = sendto (buffer, n+taille_no_seg)
• int n = recvfrom (...)
• memcopy ()

Some optimization

If C or Java :

1. Read a piece of file and buffering
2. Send
3. receive and buffering
4. Write

!! Multiple client : 1 principal thread 3 way handshake : syn syn-ack+port ack then new thread which communicate on port

Start the thread BEFORE the synack+port or we loose the first packet !

TODO

• --Calcul du débit--
• RTT to calcul the TimeOut
• How to change de mode ?
• Slow start
• Congestion avoidance
• NewReno

Point to talk about during presentation

• What we get about the client...
• How we handle multiple client : 1 process per client + process to accept client
• How we parse the file -> all format in one Array
• Congestion windows : No slow start because random
• Explain that we hardcode the initial timeout instead of calculing it on the synack-ack because it was struggling for peanuts
• Explain the karn's algorithm for RTT calcul, the infinite loop problem on timeout and its fix, RTTd and RTTs