Patent ID: 8363549

Claim:
A method comprising: receiving, with a primary network element of a high-availability cluster, a first packet of a packet flow, the first packet having a first sequence number; receiving, with the primary network element, a second packet of the packet flow, the second packet having a second sequence number; calculating a first difference value comprising a difference between the second sequence number and the first sequence number; after determining that the first difference value exceeds a first update window size value associated with the packet flow, wherein the first update window size value is based on a window size value associated with the packet flow and a window scale factor associated with the packet flow, sending, with the primary network element, a first update message comprising the second sequence number to a backup network element of the high-availability cluster; receiving a modified window size value for the packet flow; calculating a second update window size value according to the modified window size value and the window scale factor; receiving a third packet of the packet flow, the third packet having a third sequence number; calculating a second difference value comprising a difference between the third sequence number and the second sequence number; and after determining that the second difference value exceeds the second update window size value, sending a second update message comprising the third sequence number to the backup network element.