TCP Question

To summarise:
1) Sender and receiver negotiate the window size (among other things) when the connection is established so both ends 'know'
2) The way the sequence number is generated allows the receiver to know where a segment fits in the window, or to reassemble the packets into their proper order (whichever makes it easier to understand)
3) Both ends have timers. Sender has a timer that runs waiting for the ACK for the segments sent once the window size is reached. Receiver has a timer running as segments come in that waits for either further segments or an end signal so that if the connection hangs it can take action to recover
Have a wdae through www.tcpipguide.com/free/t_TCPReliability...esandProtocolMod.htm and see if that helps make things clearer

Cheers everyone, i sort of get it now. The text posted at the start of this thread said that the Sender had a timer (but didn't mention that the recipient also has a time), the next paragraph then said that the recipient would ask for missing packet 5. I was a little confussed on how it knew it was missing, so it makes sense that it also has a timer.

Thanks for the link to TCPGUIDE, i ordered the book off Amazon on Monday as this is now facinating me

Think i will still give the article a browse to get a few other things clear up.

Thanks for everyones time for replying

No problem smurf. Once you understand it you can explain it to us!