Thanks all for your responses.


I am new to Kamailio, so appreciate if some one can help me with sample code where kamailio routes call to another FreeSWITCH server if 1st FreeSWITCH server does not respond in some time, say 3 sec. Btw I have a query on this approach. Consider a following scenario - 

kamailio is configured w/ 2 FreeSWITCH servers in dispatcher and with configuration where on not receiving response to INVITE in 3 sec, kamailio will forward the call to another FreeSWITCH server.
kamailio receives INVITE and forwards INVITE to FreeSWITCH #1
FreeSWITCH #1 receives INVITE, but 100 trying response could not reach to kamailio bec of network break, say for 4 sec.
So After 3 sec, since kamailio does not receive any response from FreeSWITCH #1, it forwards INVITE to FreeSWITCH #2
FreeSWITCH #2 responds with 200 OK and kamailio receives it.
After 4 sec, when network recovers, FreeSWITCH #1 sends 200 OK to kamailio. How kamailio would behave here? Will it drops the call w/ FreeSWITCH #1?

​Thanks,

Atul Thosar

On 7 April 2018 at 21:46, Julien Chavanton <jchavanton@gmail.com> wrote:

Hi,

I would set it to a low value to make sure you avoid sending calls a Freeswitch server facing problems, in the case of Freeswitch the same GW will also handle media, if it is having hardtime repliyng to SIP OPTIONS it will very likely have problem handling the media.

It may also get worst during the call even stop responsding and loose transaction in progress or in dialog transactions later like session timers and BYEs.

Off loading it may able help other calls already using it.

You may push your strategy further thinking about :

- The risk is that you run out of GW, could be handled when ds_select is returning nothing.
- Another side effect, would be that you are sending more traffic to other GW, they must be able to handle the extra load.

In kamailio 5 there is a new algorithm that behaves better when one GW is put out of service.

“11” - use relative weight based load distribution. You have to set the attribute 'rweight' per each address in destination set. Active host usage probability is rweight/(SUM of all active host rweights in destination group).

Regards
Julien

On Mon, Apr 2, 2018 at 6:06 PM, Atul Thosar <atulthosar@gmail.com> wrote:
Hi All,
I am using Kamailio

v4.4.x to load balanced traffic to FreeSWITCH servers. I have query regarding ds_ping_interval and ds_probing_threshold. We have very high traffic (around 200-400
(CPS)
calls per sec) hitting on Kamailio which then distribute it to 2-3 FreeSWITCH servers.

What is the optimal value should I set to ds_ping_interval and ds_probing_threshold?

If I set

ds_ping_interval=2 and

ds_probing_threshold=1 then in every 2 sec, I would come to know if my

FreeSWITCH server is down/up. But by setting such low values, I afraid there would
be
lot of SIP traffic on network.
If I set high (say

ds_probing_threshold=5) then I may loose high number of calls (200 CPS, I will loose 1000 calls) in case

FreeSWITCH server is down.

As I said earlier we have very high traffic hitting on Kamailio, can't kamailio use INVITE itself to probe FreeSWITCH server is down/up? In case of low traffic can't it switch over to OPTION mechanism?

--
Thanks in Advance
,

Atul

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