[Standards-JIG] JEP-0138 (Stream Compression): unidirectional compression

Philipp Hancke fippo at goodadvice.pages.de
Mon Feb 27 06:55:46 UTC 2006


Hi,

business rules of JEP-0138 state that stream compression MUST be used
in both directions. It might be desirable to have unidirectional
methods as well:

S2S is (mostly) one-way, here it would be preferable to compress only
the data sent by the originating server.

While C2S traffic is bidirectional, the amount of data received by the
client usually exceeds the amount of data sent
(see http://www.net.in.tum.de/~anja/feldmann/papers/imc03.pdf
  §6.6, figures 10&11. Those numbers are for IRC and webchats, the actual
  ratio might be different for Jabber).
Therefore, compressing traffic from server to client will yield most
of the favorable effects of stream compression while being less
expensive in terms of memory consumption and cpu time.

Drawback:
unidirectional compressed streams may look weird when examined with a
packet sniffer :-)

cheers,
Philipp



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