[Freeswitch-users] Tutorial: FreeSwitch as Media Server and SBC for Kamailio 3.1

[Daniel-Constantin Mierla]

On 11/30/10 5:31 PM, mazilo wrote:
>
> Daniel-Constantin Mierla wrote:
>> Hello,
>>
>> On 11/30/10 3:53 PM, mazilo wrote:
>>> Daniel,
>>>
>>> Thanks for the update. I took a glance at the links and the
>>> configurations
>>> seemed to be simple and straightforward. I am tempted to go ahead, but I
>>> need my FS to also serve a PBX System. Is it possible to configure FS as
>>> a
>>> PBX System as well as an SBC to Kamailio without any conflicts and
>>> (additional) security issues?
>> PBX has lot of features, you know, is not like a very clear definition.
> What I meant by PBX system is the basic (default) PBX features from
> FreeSWITCH. For instance, when I have my FS up for the first time, I just
> configured my ATA to register to my FS as an extension, added several
> trunks, and can use it right the way to place/receive calls. What I meant is
> if I configured my FS as an SBC to Kamailio, will the existing
> configurations still be working along with the new addition as SBC to
> Kamailio?

If you have just several extensions, then it makes no sense to deploy 
Kamailio unless you need some features that you don't find in FreeSwitch.

As I mentioned, this architecture is suitable for large VoIP platforms, 
that can be either call volume or number of active lines.

You can simply use Kamailio as a front end to FreeSwitch for the purpose 
of traffic filtering (e.g., attacks protection), load balancing and high 
availability of a FS farm, then practically you have same services like 
you have now with FS only, with the perspective of growing easier.

> Of course there are some PBX functionalities that can be implemented in
>> Kamailio, like call hunting -- it is a matter of your design decision.
> This may not be a bad idea. BTW, since I am not familiar with Kamailio, is
> it possible configure Kamailio with a trunk to register to a VoIP service
> provider, i.e.  http://callcentric.com CallCentric , etc.?

There is this possible, but since Kamailio is not a back-to-back user 
agent, there are couple limitations in this regard. Registration for 
inbound calls is easier and without any issues, but doing calls through 
a provider that requires user authentication has some limitations, since 
kamailio, as a SIP proxy in this case, will need to authenticate like a 
user (end device). If the provider uses Kamailio (or SER-based SIP 
servers), then it works, otherwise it is a CSeq issue that can be solved 
with some nasty tricks in config, but you better stick to FS in this case.

Btw, probably many freeswitch fans will appreciate this one as well - 
Kamailio routing logic done entirely in Lua:
http://asipto.com/u/h

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
Kamailio (OpenSER) Advanced Training
Jan 24-26, 2011, Irvine, CA, USA
http://www.asipto.com