I have got the following question from a course:
"Assume a TCP connection over the internet with a useable bandwith of 300Mbps. Assume that some packets are transported with a very high delay. At which delay time serious problems may occure? Is this a realistic problem?"
I calculated that at a delay time of ~2 minutes, there will be an overflow within the sequence counter (if you assumed that it started with 0). According to RFC the sequence counter will overflow to zero. I found no "what to to if this happens" within the RFC, but maybe i overlooked it.
My question is: What will happen? Is this simply a limitation of TCP? Are there workarounds (except of using a larger sequence counter)?
Best Answer
Well, the relevant RFC tells you how to do this right (and actually solves the problem). See http://www.apps.ietf.org/rfc/rfc1323.html section 4.