[SR-Users] Kamailio propagates 180 and 200 OK OUT OF ORDER

[Luis Rojas G.]

Good day,

I am testing the dispatcher module, using Kamailio as stateless proxy. I 
have a pool of UAC (scripts in SIPP) and a pool of UAS (also scripts in 
SIPP) for the destinations. Kamailio version is kamailio-5.3.3-4.1.x86_64.

Problem I have is, if UAS responds 180 and 200 OK to Invite immediately, 
sometimes they are propagated out of order. 200 OK before 180, like this :



UAS is 172.30.4.195:5061. UAC is 172.30.4.195:5080. Kamailio is 
192.168.253.4:5070

Difference between 180 and 200 is just about 50 microseconds.

My guess is that both messages are received by different instances of 
Kamailio, and then because of context switches, even though the 180 is 
received before, that process ends after the processing of 200. However, 
I had the idea that in order to avoid these problems the kamailio 
processes synchronized with each other using a shared memory. I tried 
using stateful proxy and I obtained the same result.

By the way, anyone has any idea about how Kamailio's share memory is 
implemented? It clearly does not use the typical system calls shmget(), 
shmat(), because they are not shown by ipcs command.

Before posting here I googled, but I couldn't find anything related to 
this. I can't believe I am the only one who ever had this problem, so I 
guess I am doing something wrong...

Please, any help. I'm really stuck on this.

Thanks.

-- 
Luis Rojas
Software Architect
Sixbell
Los Leones 1200
Providencia
Santiago, Chile
Phone: (+56-2) 22001288
mailto:luis.rojas at sixbell.com
http://www.sixbell.com

-- 
Luis Rojas
Software Architect
Sixbell
Los Leones 1200
Providencia
Santiago, Chile
Phone: (+56-2) 22001288
mailto:luis.rojas at sixbell.com
http://www.sixbell.com

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