We used per-packet tx timestamps and timer based reordering detection in Teclo's TCP stack[0] in 2011 and later. The important bits with a time-based reordering

We used per-packet tx timestamps and timer based reordering detection in Teclo's TCP stack[0] in 2011 and later. The important bits with a time-based reordering detection heuristic are to a) make it dynamically adjust to observed network conditions, b) make it take into account some of the factors that affect reordering probability. E.g. reordering is much more likely for packets of different size than of the same size. BTW, the assumption you quoted that there won't be more than 10ms of reordering is false. Reordering of up to 50ms was common in mobile networks. [0] https://www.snellman.net/blog/archive/2015-08-25-tcp-optimization-in-mobile-networks/ https://www.snellman.net/blog/archive/2015-08-25-tcp-optimiz...