TE30, can’t initiate a call using SIP.

TE30 can’t initiate a call using SIP. And the sip server didn’t receive any invite message from the TE30.

Capture package from the TE30 side. It shows the TE30 has sent invite message out and due to no response for several times, stop trying.

So, it should be the network issue and the packet is blocked due to some resson. Check the MTU in the network with command “ping IP –l XX”. The result is as follows. The maximum data package can sent out is 1468 bytes. So, the network MTU should be 1468+28=1496 byes.

172.17.254.13 bytes=1400  à reply successful

172.17.254.13 bytes=1468  à reply successful

From size start from 1469 reply getting failed.

172.17.254.13 bytes=1469  à reply fail

172.17.254.13 bytes=1500  à reply fail

Change the MTU setting on the TE30 and set the value to be 1496. Then the issue is fixed.