Flow Control

This animation illustrates the interaction between a TCP sender and receiver.
Both of them have an application and a send/receive buffer.

The application at the senders side tries to transmit a file with a certain size to the Receiver.
The application at the receivers side consumes chunks of 2Kbytes (except the very last one) from the send/receive buffer at random time.

When a packet is received the ack always contains the number of bytes the receiver has left in his buffer (advertised window). If the sender gets a advertised window size of 0 he just sends 1 byte until the application on the receivers side has consumed and so there is some space in the receivers buffer.

configuration

the size of the file the sender application wants to send to the receiver

size of the buffers

propagation time between sender and receiver

pause or resume scrolling of the simulation

start or restart the simulation

legend

 
 ack
 
 data
buffer
application
sender
buffer
application
receiver

coded by Johannes Kessler 2012