High Quality Content by WIKIPEDIA articles! Van Jacobson TCP/IP Header Compression is a data compression protocol described in RFC 1144, specifically designed by Van Jacobson to improve TCP/IP performance over slow serial links. Van Jacobson compression reduces the normal 40 byte TCP/IP packet headers down to 3-4 bytes for the average case. It does this by saving the state of TCP connections at both ends of a link, and only sending the differences in the header fields that change. This makes a very big difference for interactive performance on low speed links, although it will not do anything about the processing delay inherent to most dialup modems.