[Standards] Stanza Size Limits (was Re: [jdev] Communicate between two client instances of the same ID)

Pedro Melo melo at simplicidade.org
Thu Sep 4 08:11:59 UTC 2008

On Sep 4, 2008, at 8:53 AM, Kevin Smith wrote:

> On Wed, Sep 3, 2008 at 11:15 PM, Pedro Melo <melo at simplicidade.org>  
> wrote:
>> Sure but as a server admin I would not admit a client negotiating  
>> a larger
>> stanza than my own C2S or S2S limits.
> Sorry - I'm jumping in mid-thread again, but I don't remember seeing
> this discussed.

I was replying to this part of Justin email:

> If you set a small value for the server policy then you'd be fine,  
> but that's
> not very flexible.  For example, most desktop clients are surely  
> capable of
> handling a 1MB stanza, but for some reason you cap your server at a  
> much
> smaller 64KB.  And even 64KB is probably too much for a mobile.  So  
> a flat
> maximum is not ideal.

I interpreted that desktop clients have the capabilities of handling  
large stanzas.

I was just clarifying that even if a client can perfectly handle  
large stanzas, I think that no server admin will allow a client to  
bypass their own rules.

> If stanza sizes are a stream feature, what's the work flow where one
> server wants to s2s with another server with a lower stanza size
> (given that its clients could be sending full-size stanzas)?

Stanzas above the destination S2S limit will be rejected.

This is like the Path MTU problems of IP.

We where discussion "last mile" MTUs but those are only part of the  
problem, actually.

I still like having something at the last mile, it prevents silly  
problems, but it wont avoid stanza-too-big errors.

"Path MTU" is something that is important for IBB for example.

Best regards,
Pedro Melo
Blog: http://www.simplicidade.org/notes/
XMPP ID: melo at simplicidade.org

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