The SigComp (Signaling Compression) offering from Aricent
enables compression and decompression of messages to
be sent across the networks, which have stringent bandwidth
restrictions. SigComp implements a virtual machine, which
allows applications to dynamically select the compression
algorithm of their choice. The product has been positioned
as an independent component, which can be integrated with
any protocol stack.
SigComp Architecture
Many application protocols used for multimedia communications
are text-based and engineered for bandwidth rich links. As
a result, the messages are not optimized in terms of size.
For example, typical SIP messages range from a few hundred
bytes up to many thousand bytes. With the planned usage of
these protocols in wireless handsets, as part of 2.5G and
3G cellular networks, large message size becomes a problem.
With low-rate IP connectivity, transmission delays are significant.
Call setup and feature invocation are adversely affected by
account retransmissions and multiple messaging, as required
in some flows. SigComp provides a solution to this problem
by offering robust, loss-less compression of application messages.
Due to the heavy signaling involved and SIP, being a text
based protocol, 3GPP IMS Release 5 standards mandates SigComp
(Signaling Compression).
SIGCOMP stack can be used in 3G User terminals and all types
of CSCFs. It should be integrated with the applications for
deployment and cannot be used independently in any deployment.
The major components of SigComp are:
- Compressor
The Compressor is the component that compresses
the messages and uploads the ByteCode for the corresponding
decompression algorithm to the UDVM as part of the SigComp
message.
- Decompressor (UDVM)
UDVM provides a mechanism to uncompress messages
by interpreting the corresponding ByteCode. The UDVM can
be used to decompress the output of various compressors
such as DEFLATE (RFC-1951).
- State Handler
The State Handler retains information between received
SigComp messages and thus, eliminates the need to send decompression
instructions with each of the compressed message.
Features:
- Agnostic of compression algorithms
- Supports state handling for better compression ratio
- Complies with RFC 3320
- Pluggable with any protocol stack
- Provides APIs for easy integration with any application
- Supports DEFLATE compression algo (RFC 1951)
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