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Protocol Action: Signaling Compression to Proposed Standard
The IESG has approved the Internet-Draft 'Signaling Compression'
<draft-ietf-rohc-sigcomp-07.txt> as a Proposed Standard.
In the same action, the following Internet-Drafts were approved for
publication as Informational RFCs:
o SigComp - Extended Operations
o Signaling Compression Requirements & Assumptions
These documents are the product of the Robust Header Compression
Working Group. The IESG contact persons are Allison Mankin and Scott
Many application protocols used for multimedia communications are
text-based and have not been optimized in terms of size. For
example, typical SIP messages range from a few hundred bytes up
to two thousand bytes or more.
With the planned usage of these protocols in wireless handsets as
part of 2.5G and 3G cellular networks, the large message size is
problematic, especially because of transmisssion delay concerns.
Taking into account retransmissions, and the multiplicity
of messages that are required in some flows, call setup
and feature invocation are adversely affected. SigComp provides a
means to eliminate this problem by offering robust, lossless
compression of application messages.
The Sigcomp document presents the architecture and pre-requisites of the
SigComp solution, the format of the SigComp message and the Universal
Decompressor Virtual Machine (UDVM) that provides decompression
functionality. Arbitary applications ar supported by transferring
a well-formed UDVM for the use of a flow or flows from the sender
to the receiver.
SigComp is offered to applications as a layer between the application
and an underlying transport. The service provides is that of the
underlying transport plus compression. SigComp supports a wide range
of transports including TCP, UDP and SCTP [RFC-2960].
The two informational drafts provide background to the design
(requirements) and a set of optimization techniques for UDVM
construction (extended operations) that may either be adopted by
implementations or used as a model for optimizations to be
added in future.
Working Group Summary
The working group had strong agreement to advance these drafts.
No problems were found during IETF Last Call. There have been
two independent prototyping developments of sigcomp, with
resuls of both the protocol and interoperation tests being
fed into the working group effort before last call. Allison
Mankin reviewed the documents for the IESG.