[Kamailio-Users] [SR-Users] force_rtp_proxy() vis-a-vis BYE

Daniel-Constantin Mierla miconda at gmail.com
Tue Jul 7 19:47:06 CEST 2009



On 07/07/2009 07:27 PM, Iñaki Baz Castillo wrote:
> 2009/7/7 Daniel-Constantin Mierla <miconda at gmail.com>:
>   
>>> I use nat-traversal module and it's MUCH MUCH more powerful than
>>> nathelper, for sure.
>>>       
>> I do not agree at all with this, when comes to flexibility. nat_traversal
>> main problem is the relying on dialog module, which adds lot of overhead to
>> a proxy.
>>     
>
> Not sure now if dialog module is fully required for all the cases...
> It's just required if you want to mantain nat keepalive for calls
> initiated by non registered users.
>   
it does not bind to usrloc, so I think it has no idea who is registered 
or not, unless it is done via some parameters.


>> For presence, like for registration, the keepalive should be done by the
>> endpoint (registrar, presence server), otherwise you get into scalability
>> issues.
>>     
>
> Imagine a presence agent machine (behind NAT) subscribing to the
> presence of some users without registering.

First I think that is not a typical use case, but more than that, 
imagine you have 100 000 presence sessions spread across couple presence 
servers and about the same number of calls going through your proxy.

Do you think it will deals nicely doing pings? While for calls, nat 
pinhole is handled by the registrars, same can be done by the presence 
servers.

Architectural point of view, it is even better doing so, as once there 
is no reply, the presence dialog can be destroyed and resources freed on 
server side. With nat_traversal approach, you consume twice resources in 
the server side, as you keep dialog attributes on proxy and presence 
server, therefore you double the scalability issues.

>  How to mantain the
> keepalivee in Kamailio (without using nat_traversal module)? The dirty
> solution would be decrease the notification interval, that of course
> would be a wrong choice.
>   
Why would be that more wrong than sending keepalives from a stateful 
proxy? See above, you keep the dialog only once on server side.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
http://www.asipto.com/




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