Reduce size of To INVITE packet. MTU problem.

1. Brekeke Product Name and Version:
SIP Server Advanced, 3.14.7.4

2. Java version:
Redhat OpenJDK 11.0.21-1

3. OS type and the version:
Windows Server 2019 datacenter

4. UA (phone), gateway or other hardware/software involved:
Voicent IVR

5. Your problem:
I am receiving an INVITE from carrier via TLS but I must change transport to UDP for IVR. TLS is not available. The MTU size of 1500 causes errors and fragmented packets.

I need to go from 1514 transmitted packet size to under 1500.
The overhead of the transport conversion is causing the issue.

Is there any way to reduce the packet size by as much as I can get, at least 20 or so.

Deploy Patterns
--------------------
$b2bua=true
$auth=false
$trasport=UDP
To:xxxx@10.10.x.x:5060

Using $b2bua=true reduces the size of the SIP packet.

It seems you already put it in the DeployPatterns.
but do you still have the issue?

Yes, the problem persists with the current deploy patterns shown.

Which parts of SIP packet are consuming a packet size? SDP?