Delta encoding (also called delta compression) is a way to update web pages by sending the “diffs” or deltas between versions of a web page. The server (proxy or origin) sends only what has changed in the page since the last access. This technique greatly reduces the amount of data that is sent from server to browser. In some cases with pages that change slightly, the deltas are on the order of a few TCP/IP packets. As about 32% of page accesses are first-time visits, about 68% of page visits are eligible for delta compression.