[SR-Users] Kamailio Via: header issue

[Laura]

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 at 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 at 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 at 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