[Standards] Council on Stanza Repeaters without Multicast

Dave Cridland dave at cridland.net
Wed Apr 2 23:47:08 UTC 2008


On Thu Apr  3 00:32:54 2008, Tobias Markmann wrote:
> On Thu, Apr 3, 2008 at 1:22 AM, Dave Cridland <dave at cridland.net>  
> wrote:
> > On Wed Apr  2 23:22:12 2008, CvL at mail.symlynX.com wrote:
> >  1) It's much simpler to implement, and2) Given that we are (or  
> should be)
> > encrypting every S2S connection, then TLS is giving us  
> compression anyway,
> > and moreover, it's cheaper to compress than not to compress.
> 
> That may be right from the spec but in real world it's a lot worse.  
> TLS
> doesn't really give use compression anyway.
> See this from the man page on SSL_COMP_add_compression_method(3)  
> (OpenSSL):
> 
> > The TLS standard (or SSLv3) allows the integration of compression  
> methods
> > into the communication. The TLS RFC does however not specify  
> compression
> > methods or their corresponding identifiers, so there is currently  
> no
> > compatible way to integrate compression with unknown peers. It is  
> therefore
> > currently not recommended to integrate compression into  
> applications.
> > Applications for non-public use may agree on certain compression  
> methods.
> > Using different compression methods with the same identifier will  
> lead to
> > connection failure.
> 
> 
> The only way to make use of TLS's compression capabilities is to  
> get all
> XMPP servers and clients use the same compression methods and same
> identifiers for those methods otherwise TLS just does NOT do  
> compression.
> Since this seems very unlikely I prefer applying XEP-0138 and then  
> TLS.

OpenSSL has negotiated the DEFLATE compression codec defined in RFC  
3749 since 0.9.8 came out - the documentation may be wrong, but it  
always is with OpenSSL.

Dave.
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