Reconsidering usage of standalone packets for congestion indication

With the introduction of active queue management and explicit congestion notification, Internet router queues have become an active part of congestion control. It is pointed out that data flows with one packet per direction (standalone packets) are not allowed to take advantage of explicit congestion notification (ECN), which means that they will experience unprivileged handling by intermediate routers. A proposal is presented for reducing the unintended drops of standalone packets by active queue management when it is combined with ECN. The method is backwards compatible and can be deployed incrementally without introducing security risks. The method is simulated on domain name system traffic showing significant improvement of user experience.