2 options:
Dynamic Desirable (DTP Active) - switch port sends DTP messages to initiate trunk with connected switch
Dynamic Auto ( DTP Passive ) - switch port waits for DTP messages to initiate trunk interface
Two ports connected together with DTP passive will never initialize trunk interface as both only passively waiting for DTP messages from DTP active switch.
As DTP behavior is not always desirable we can switch off DTP by using command:
switchport nonegotiate - trunk port
switchport mode access - access port (switchport nonegotiate can be also use on access port to make it visible in config)