Packet reordering (posted 2002-06-29)

During the second week of April there was some discussion on reordering of packets on parallel links at Internet Exchanges. Equipment vendors try very hard to make sure this doesn't happen, but this has the risk that balancing traffic over parallel links doesn't work as good as it should. It is generally accepted that reordering leeds to inefficiency or even slowdowns in TCP implementations, but it seems unlikely reordering will happen much hosts are connected at the speed of the parallel links (ie, Gigabit Ethernet) or there is significant congestion.