at a customer I have a problem of sudden drops on Trunk VoIP on UCM 126.96.36.199 with 4 phones GXP1830 188.8.131.52. The problem occurs at random on all phones. So the customer is in an external conversation and sometimes suddenly the conversation falls out, for no apparent reason.
The only element I currently have is the attached screen, as being a problem that occurs very rarely is difficult for me to leave “Network Troubleshooting” listening.
I understand that it could be everything, but my tests to date have been:
1 - reverse the phones between them by also changing the data network point
2 - restart router, firewall and UCM and the same phones
3 - I have a doubt about the Zyxel GS-1900-24HP POE Switch (not supplied by me and anyway I want to try to replace it next time)
4 - the data connection is on the Draytek Router and at the level of stability does not show any problems.
If someone had ideas and advice on what to try to do, I would be happy.