Analysis on Packet Resequencing for Reliable Network Protocols

Protocols such as TCP requires packets to be accepted (i.e., delivered to the receiving application) in the order they are transmitted at the sender. Packets are sometimes misordered in the network. In order to deliver the arrived packets to the application in sequence, the receiver’s transport layer needs to temporarily buffer out-of-order packets and re-sequence them as more packets arrive. Even when the application can consume the packets infinitely fast, the packets may still be delayed for resequencing. In this paper, we model packet mis-ordering by adding an IID random propagation delay to each packet and analyze the required buffer size for packet resequencing and the resequencing delay for an average packet. We demonstrate that these two quantities can be significant and show how they scale with the network bandwidth.