Hello,

the long Via branch is because of using topoh module. Do you need that?

The alternatives would be:

 - disable topoh module

 - or configure the kernel to do udp defragmentation (should be default in modern linux)

 - or switch to tcp/tls

 - or try to use the new topos module in 4.4 -- not that it is not well tested and you should not go with it in production directly. Any issue encountered with topos should be reported on kamailio project on github and I will take care fixing them.

Cheers,
Daniel


On 24/05/16 09:57, Laura wrote:
Good morning list,

I need to ask you a question about a problem we are fighting on our VoIP
platform based on Kamailio 4.3.5.
Our platform is made by more nodes over Europe countries, and we are
encountering a problem with the size of the SIP package which, exceeds
the physiological limit of about 1350 bytes.
The real problem is caused from Via: Header (inside the SIP packet)
which is added to each element of the system for transit on the call.
>From what we have analyzed, the problem is not so much due to the number
of entered Via: records but, by the fact that they contain a branch
parameter extremely long.

Here the call flow example from CARRIER A —> Kamailio1 —> Kamailio2 —>
CARRIER B

Extract from SIP message sent from CARRIER A to K1

INVITE sip:999912341234@192.168.158.42 SIP/2.0.
Via: SIP/2.0/UDP 192.168.220.141:5060;branch=z9hG4bK49e4301c;rport.

Extract from SIP message sent from K1 to K2

INVITE sip:999912341234@192.168.127.244 SIP/2.0.
Record-Route: <sip:192.168.158.42;lr;did=194.a0f1;nat=yes>.
Via: SIP/2.0/UDP
192.168.158.42;branch=z9hG4bK0635.7c1e97c2d5c01ea98e8d0e7fa23a3822.0.
Via: SIP/2.0/UDP
192.168.158.42;branch=z9hG4bKsr-j4IPOlV7MGQKatycM.cuOBV4OBVLMGZfWxF-W.y6Mx1LgRWIC9gIgx4fzxj7MBP7MBVAOBF4M.1jmxuqC93X3heroEWvH9vsCFN43qd4zRj4Mlyf3l1LNSQLpx4uMx3A.

Extract from SIP message sent from K2 to CARRIER B

INVITE sip:999912341234@192.168.65.248 SIP/2.0.
Record-Route: <sip:192.168.127.244;lr;did=194.5122;nat=yes>.
Via: SIP/2.0/UDP
192.168.127.244;branch=z9hG4bK0635.f843472880b380acde3a33732975fde9.0.
Via: SIP/2.0/UDP
192.168.127.244;branch=z9hG4bKsr-j4IPOlV7MGQKatycW.F7MBj4OBFuzGZ4MB1LNSQLpx4uMx3AzuaVHRaYpB1JNEt736cQkBIvalaJmly6Mlj7W6Mfg.qw3leqWRMAMRKrz.rIzSPAg.pE3.Vl3.MZMBV7My**.
Via: SIP/2.0/UDP
192.168.127.244;branch=z9hG4bKsr-j4IPOlV7MGQKatycW.F7MBj4OBFuzGZ4MB1JNEt736cQkBIvalaJmwWLORv4mK0Hot3w.jpam6t4kRWWOEWu.4eRWFQGKqfWauYEKwrSOKN7k.gWkxtMgue9mjMsg4IhkxaEkhrbW4uGjxpWPIg0.4eSWF47MRY1kUKfPlqlRxWvg9e5aKp6mxI6N4WS.BPlNRP4kIebWFudkR3loxtM.IWa.U0ZWUKWkxW0.


Is there anyone here with the idea how to solve this problem ?

Best regards



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-- 
Daniel-Constantin Mierla
http://www.asipto.com - http://www.kamailio.org
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda