US Patent 9667560 Flow sequencing

Some embodiments of the invention provide a method for assigning a data flow-specific sequential value to each packet of a data flow that is sent from a source endpoint to a destination endpoint in a network. In some embodiments, the source endpoint receives the data flow from a source application while the destination endpoint delivers the data flow to a destination application. The method of some embodiments assigns separate monotonically incrementing values to the packets of each data flow between the same two endpoints by inserting the incremental values into the IPv4 identification field in each packet's IP header. Some embodiments use this sequential value in order to discover any potential error condition in packet transmission. Some embodiments use the IPv4 identification field values to calculate the transmission rate of a data flow at only one observation point.