[SR-Users] need help for newbie in Kamailio

Reda Aouad reda.aouad at gmail.com
Tue Mar 20 10:02:36 CET 2012


Hello,

In SIP, session timers can be used to periodically ping the UAC (using a
re-INVITE or UPDATE) to know if it's alive or not. Then action can be taken
- terminating the call.

Kamailio has the SST (SIP Session Timer) module which only enforces a
minimum session timer value for UACs, but not a maximum one. It doesn't
ping the UACs neither. This is fine because the RFC stops here. A nice
improvement to Kamailio would be to augment the SST module with a feature
which enforces a maximum session timer value and pings UACs. Another
suggestion would be to rely on nathelper's keepalive results to take a
decision after a keepalive times out, but then we'd have to terminate all
dialogs in which the UAC that is not responding is present, since
nathelper's keepalive are out-of-dialog. No very neat, but functional.

And I don't think the dialog module can do anything about this problem.

I know that what I am suggesting may not be defined in RFCs, and so are
some features of SIP servers, but in my opinion should be implemented as it
adds a great value to Kamailio.

We cannot rely on RTP timeout since a UAC may use a silence-detection codec
and be silent for some time, or may put a call on hold for a while, not
sending RTP packets in both cases. This is why RTP timeout detection is not
reliable. Anyway, mediaproxy timeouts ONLY AND ONLY in the case it doesn't
receive RTP packets from BOTH UACs, not only one, for the reasons
mentioned. I don't know about rtppoxy, maybe others can tell more about it.

One solution if you really need to solve your problem would be to put a
B2BUA in the SIP path, such as Asterisk or FreeSwitch. They enforce a
maximum session timer which UACs can use to ping themselves every now and
then, and Asterisk can even ping the UACs and terminate the call if one of
them doesn't respond. The downside: lower performance and higher cost.
Asterisk is very heavy and Kamailio can handle many, many more calls, so
you'll have to load balance to several Asterisk servers if you have a
single Kamailio machine handling thousands of simultaneous calls.

Kamailio developers out there, what about boosting the SST module with new
features? Or creating an SSTX module?

Reda



On Tue, Mar 20, 2012 at 07:35, SamyGo <govoiper at gmail.com> wrote:

> Hi,
>
> Yes that is the behaviour when the media isn't flowing through a
> regulatory tool (in-terms it sees the media and know call is actually going
> on rtpproxy/media-proxy)  but in the absence of any such tool SIP server is
> not aware that the call-media is still in progress or is dead ! so it
> always assume that the call is active and hence the BYE signals are never
> originated from server end to shutdown the call.
>
> I am definitely not an expert but I am guessing that dialogue module do
> some keepalive tests for an ongoing session and not sure what it do if
> either end fails to respond !!
>
> Regards,
> Sammy
>
> On Tue, Mar 20, 2012 at 11:04 AM, Vineet Menon <mvineetmenon at gmail.com>wrote:
>
>> i guess it should time out...the other end...since it has no way of
>> knowing that the other end is no more present...
>>
>> Regards,
>>
>> Vineet Menon
>>
>>
>>
>>
>>
>> On 20 March 2012 11:30, Rabary <teddy at gulfsat.mg> wrote:
>>
>>> Hi mailing,
>>>
>>> Newbie to kamailio, I follow this tuto http://nil.uniza.sk/sip/**
>>> kamailio/adding-mysql-support-**kamailio-31-debian-lenny<http://nil.uniza.sk/sip/kamailio/adding-mysql-support-kamailio-31-debian-lenny>for the registration SIP via mysql database and it works fine, but I saw
>>> that when during the call we disconnect the called UAC from network or turn
>>> the power off the caller UAC don't hangup.
>>> Is there any tool for how to hangup call when the UAC on the other side
>>> has no network connection or it isn't power on durring a call ?
>>> I heard for mediaroxy or rtpproxy but I don't know if them can do what I
>>> except to haveand we also use ip routing to make kamailio server to
>>> communicate with the UAC so we don't use NAT.
>>>
>>> Our topology is:
>>> kamailio (with public IP address) ---> cisco switch ---> LAN ---> UAC
>>> (with private IP address)
>>>
>>> Thanks in advance.
>>>
>>> --
>>> Inutile d'imprimer ce mail
>>>
>>>
>>> ______________________________**_________________
>>> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
>>> sr-users at lists.sip-router.org
>>> http://lists.sip-router.org/**cgi-bin/mailman/listinfo/sr-**users<http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users>
>>>
>>
>>
>> _______________________________________________
>> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
>> sr-users at lists.sip-router.org
>> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>>
>>
>
> _______________________________________________
> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
> sr-users at lists.sip-router.org
> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20120320/b7d25480/attachment.htm>


More information about the sr-users mailing list