Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. The EPIC inputset is a list of fields from the protocol stack to be compressed, and for each field a choice of encoding techniques together with the probabilities that they will be used. The output of EPIC is a set of optimally efficient compressed header formats for the chosen protocol stack, and an automatic mechanism for translating between compressed and uncompressed packet formats. SCTP is designed to transport PSTN signaling messages over IP networks but its rich feature set makes it capable of many broader applications.
EPIC is basically a programmable compressor that can be configured to handle any protocol stack.
EPIC allows the SCTP field behaviors to be specified in the form of an inputset, and then uses this information to automatically build an optimally efficient set of compressed header formats. The following chapter discusses the new features of the SCTP protocol and how they may be efficiently compressed. One of the most important innovations of SCTP is the multi-streaming function. This feature allows data to be partitioned into multiple streams where each stream is delivered independently, so in-sequence delivery can be guaranteed only for packets within a single stream. The advantage of this technique is that when a packet is lost, only the data from the corresponding stream is delayed whilst the packet is retransmitted.