[Standards] Binary data over XMPP

Fabio Forno fabio.forno at gmail.com
Wed Nov 7 22:27:34 UTC 2007


On Nov 7, 2007 1:56 PM, Dave Cridland <dave at cridland.net> wrote:
> >
> Yes, base64 is acceptable here, although bear in mind that over a
> charged-by-transfer medium - such as many mobile phone tariffs - that
> 100k image is transferred as 133k, and 33k that you didn't really
> need to transfer sounds like an additional cost we could drop if we
> had the technology to do so. It's not a driver for it, though, I
> agree.

We're developing a mobile client and we think that kind of information
should be threated in a different manner. In mobiles networks regular
socket connections have many problems (mainly disconnection handling
that forces a new login) and therefore we prefere bosh based
connections. Bosh has also the advantage that it may act more
intelligently than a simple proxy: the connector could be an agent
shaping information in more a suitable way for the mobile client
(optimized compression, caching, sending only the diffs of some data
as rosters, avatars...). Moreover large amounts of binary data
exchanaged with mobiles are very unlikely, so I don't see the
necessity of making xml streams more complex for use cases that are
not well defined, if not improbable.
What would be nice (and we're making some thoughts about it) is binary
bosh binding, with binary xml and binary data if necessary. Binary xml
+ compression is by far the most bandwidth efficient way for
exchanging xml and it may have the not trascurable advantage of being
able to implement parsers in very small clients (e.g. pic based nodes
in sensor networks). IMHO this is the only approach allowing full
compatibility with existing installations and ibb binary data for the
few clients that really need it. For regular socket based clients, as
others have already pointed out, there always alternatives and ibb is
the fallback for the few clients / applications that cannot do
otherwise.

-- 
Fabio Forno, PhD
Istituto Superiore Mario Boella
Jabber ID: xmpp:ff at jabber.bluendo.com
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