SigComp

The Session Initiation Protocol (SIP) is a text-based protocol for initiating and managing communication sessions. The protocol is extended by the SIP-events notification framework to provide subscriptions and notifications of SIP events. One example of such event notification mechanism is presence, which is expressed in XML documents called presence documents. SIP can be compressed by using Signaling Compression (SigComp), which is enhanced by using the SIP/ Session Description Protocol (SDP) dictionary to achieve better compression rates. However, the SIP/SDP dictionary is not able to increase the compression factor of (typically lengthy) presence documents. This memo defines the presence-specific static dictionary that SigComp can use in order to compress presence documents to achieve higher efficiency. The dictionary is compression-algorithm independent. [STANDARDS-TRACK]

This document describes some specifics that apply when Signaling Compression (SigComp) is applied to the Session Initiation Protocol (SIP), such as default minimum values of SigComp parameters, compartment and state management, and a few issues on SigComp over TCP. Any implementation of SigComp for use with SIP must conform to this document and SigComp, and in addition, support the SIP and Session Description Protocol (SDP) static dictionary. [STANDARDS-TRACK]

This document describes common misinterpretations and some ambiguities in the Signaling Compression Protocol (SigComp), and offers guidance to developers to resolve any resultant problems. SigComp defines a scheme for compressing messages generated by application protocols such as the Session Initiation Protocol (SIP). This document updates the following RFCs: RFC 3320, RFC 3321, and RFC 3485. [STANDARDS-TRACK]

This document provides a set of "torture tests" for implementers of the Signaling Compression (SigComp) protocol. The torture tests check each of the SigComp Universal Decompressor Virtual Machine instructions in turn, focusing in particular on the boundary and error cases that are not generally encountered when running well-behaved compression algorithms. Tests are also provided for other SigComp entities such as the dispatcher and the state handler. This memo provides information for the Internet community.

This document provides an informational guide for users of the Signaling Compression (SigComp) protocol. The aim of the document is to assist users when making SigComp implementation decisions, for example, the choice of compression algorithm and the level of robustness against lost or misordered packets. This memo provides information for the Internet community.

This document describes a mechanism that allows Signaling Compression (SigComp) implementations to report precise error information upon receipt of a message which cannot be decompressed. This negative feedback can be used by the recipient to make fine-grained adjustments to the compressed message before retransmitting it, allowing for rapid and efficient recovery from error situations. [STANDARDS-TRACK]

The Session Initiation Protocol (SIP) is a text-based protocol for initiating and managing communication sessions. The protocol can be compressed by using Signaling Compression (SigComp). Similarly, the Session Description Protocol (SDP) is a text-based protocol intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation. This memo defines the SIP/SDP-specific static dictionary that SigComp may use in order to achieve higher efficiency. The dictionary is compression algorithm independent. [STANDARDS-TRACK]

This document defines SigComp, a solution for compressing messages

generated by application protocols such as SIP [RFC-2543] and RTSP

[RFC-2326]. The architecture and pre-requisites of SigComp are

outlined, along with the format of the SigComp message.

Decompression functionality for SigComp is provided by a 'Universal

Decompressor Virtual Machine' optimized for the task of running

decompression algorithms. The UDVM can be configured to understand

the output of many well-known compressors such as DEFLATE [RFC-1951].

This document describes how to implement certain mechanisms in

SigComp (Signaling Compression), RFC XXX, which can significantly

improve the compression efficiency compared to using simple per-

message compression.

SigComp uses a UDVM (Universal Decompressor Virtual Machine) for

decompression, and the mechanisms described in this document are

possible to implement using the UDVM instructions defined in RFC XXX.

In wireless environments and especially in cellular systems, e.g. GSM

(Global System for Mobile communications) and UMTS (Universal Mobile

Telecommunications System), there is a need to maximize the transport

efficiency for data over the radio interface. With the introduction

of SIP/SDP (Session Initiation Protocol/Session Description Protocol)

to cellular devices, compression of the signaling messages should be

considered in order to improve both service availability and quality,

mainly by reducing the user idle time, e.g. at call setup. The

purpose of this document is to outline requirements and motivations

for development of a scheme for compression and decompression of

messages from signaling protocols.