UCM and phone weird scenario


Hi to all, can someone clarify to me.
Are the phones and the server should be in the same network for them to be able to communicate?
I have a weird experience. My phone and the server are on the same network which is vlan 15. but when i tried to make the port connected to the phone as Vlan 19. it still communicate with the server.
so meaning, any vlans on my network can communicate with the UCM server?


VLAN settings can be set also on router and switches. It will depend how you set your vlan.