04 Try it yourself Interactive

Lose message three, then watch each protocol react

The same scene as section 02, run twice, with the network rigged identically both times: M3 is lost and M5 overtakes M4. UDP hands every datagram up the instant it lands. TCP holds the ones it cannot deliver in order, notices the gap, and fills it. Three panes: what is on the wire, what is stuck in the receiver’s reassembly buffer, and what the application has actually been given. Watch the third pane, and watch the stat row at the end of each run. Nothing plays on its own: Next, Back and Reset, or the arrow keys.

UDP · connectionless
nothing sent yet
Amber is in flight, rose is lost, indigo is held in the reassembly buffer, emerald is delivered. The middle pane is the one that only ever fills up in the TCP run.
Press Next to begin. Each press advances the run by one event.


      

        
Sent–

        
Delivered–

        
In order–

        
Resends–

      


      

      

        
        
        
        step 0 / 0