[jdev] XMPP Ping/Keepalive: Recommended method ?

[Dave Cridland]

On Mon Jun 19 08:15:40 2006, Sergei Golovan wrote:
> On 6/19/06, Michal vorner Vaner <michal.vaner at kdemail.net> wrote:
>> On Sun, Jun 18, 2006 at 10:47:19PM -0700, 
>> ennova2005-jabber at yahoo.com wrote:
>> >    Given that the protocol itself does not seem to have a 
>> defined keep-alive
>> >    element, what is the recommended way for a client to keep its 
>> connection
>> >    alive to a XMPP server ?
>> 
>> Since XML allows any number of whitespace between elements that is 
>> just
>> ignored, you can send a whitespace if you are not in the middle of
>> stanza. It will do, NATs and other beasts will see data flowing,
> 
> The problem is that this "ping" is not a ping at all because it only
> sends data and does not expect reply.
> 
> So, some NATs and proxies still break connection if they don't see
> bidirectional flow.
> 
> 
Could you tell me which NATs do this? I'm unaware of any that handle 
timeouts differently for unidirectional data flows.


> Another issue is that with this "ping" you can't control the
> connection. If TCP connection breaks (but before TCP timeout 
> reaches -
> and it is a quite long timeout)

As far as I'm aware, there *is* no timeout on silent TCP connections.

>  both messages and "pings" goes to
> black hole and there's no way to work around this (to set some short
> internal timeout or whatever).

True, you need some acking mechanism to prevent this.

Dave.
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