[Standards-JIG] Trying to understand

Dave Cridland dave at cridland.net
Thu May 18 18:51:01 UTC 2006


On Thu May 18 18:36:11 2006, Matthias Wimmer wrote:
> <presence from='user at example.com' 
> to='jabber.org/jep0033'><addresses 
> xmlns='http://jabber.org/protocol/address'><address type='to' 
> jid='stpeter at jabber.org'/><address type='to' 
> jid='jer at jabber.org'/><address type='to' 
> jid='temas at jabber.org'/></addresses><show>xa</show><status>out for 
> a while</status><priority>0</priority></presence>
> 
> Whouldn't that be okay for all of us? I think at least we should 
> all be able to accept this protocol.
> 
> 
Sorry, but no, I can't.

Using your example:

1) Pre compression:

JEP0033: 333 octets:

"<presence from='user at example.com' to='jabber.org/jep0033'><addresses 
xmlns='http://jabber.org/protocol/address'><address type='to' 
jid='stpeter at jabber.org'/><address type='to' 
jid='jer at jabber.org'/><address type='to' 
jid='temas at jabber.org'/></addresses><show>xa</show><status>out for a 
while</status><priority>0</priority></presence>"

Normal: 408 octets:

"<presence from='user at example.com' 
to='stpeter at jabber.org'><show>xa</show><status>out for a 
while</status><priority>0</priority></presence><presence 
from='user at example.com' 
to='jer at jabber.org'><show>xa</show><status>out for a 
while</status><priority>0</priority></presence><presence 
from='user at example.com' 
to='temas at jabber.org'><show>xa</show><status>out for a 
while</status><priority>0</priority></presence>"

This is not a massive saving.

2) Post compression (using RFC1952):

JEP0033 (as above): 175 octets.
Normal (as above): 127 octets.

Of course, this is skewed in favour of the existing method, because 
it's compressed in isolation, but still, this is not a good result. 
Worth exploring, but I don't think this works out, sorry. (Strangely, 
I could tell the figures would work out like this just by looking at 
the data. I must be working with compression *way* too much.)

Dave.
-- 
           You see things; and you say "Why?"
   But I dream things that never were; and I say "Why not?"
    - George Bernard Shaw



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