This document specifies the IPFIX protocol that serves for transmitting IP traffic flow information over the network. In order Aitken, Claise Standard Track [page 1] New Information Elements for the IPFIX Information Model March 2008 to transmit IP traffic flow information from an exporting process to an information collecting process, a common representation of flow data and a standard means of communicating them is required. This document describes how the IPFIX data and templates records are carried over a number of transport protocols from an IPFIX exporting process to an IPFIX collecting process.