Hello,

On 03.04.18 03:06, Atul Thosar 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?

no matter how low you set the keepalive ping interval, it is still recommended to do failure routing in case a call sent to a freeswitch is not accepted the call.

Given the above, usually my approach is to have ds_ping_interval not that low, but like 20 to 40 seconds, and do always re-routing if a call is not accepted by a freeswitch in rather short time (say 2-4 seconds if freeswitch is in the same network). In this case, no call is lost even a freeswitch is down.

The keepalive is more for monitoring and seeing that a gateway is down for long time and do not try it in such case -- you can use event_route blocks from dispatcher to trigger some alerts if a gateway is down/up.

How to do re-routing in case of failure is shown by the kamailio.cfg example from dispatcher documentation, with a failure_route block.

Cheers,
Daniel

-- 
Daniel-Constantin Mierla
www.twitter.com/miconda -- www.linkedin.com/in/miconda
Kamailio Advanced Training - April 16-18, 2018, Berlin - www.asipto.com
Kamailio World Conference - May 14-16, 2018 - www.kamailioworld.com