Hello Ankit
When we say that DTP negotiation is ON, it means that the port is in a state where, if the proper DTP packets are sent/received, the port may change its trunking functionality. Negotiation is ON in the following states: Dynamic Desirable, Dynamic Auto or Trunk.
DTP negotiation is OFF when a port is in one of the following states: Access or Non-negotiate.
As for the exchanging of DTP frames, these are sent when a port is in the following states: Dynamic Desirable and Trunk.
DTP frames are NOT sent when a port is configured as Dynamic Auto, Non-negotiate or Access.
So, even if a port is in Dynamic Auto and doesn’t send DTP frames, it is still considered Negotiation ON because it can be affected by the DTP frames it receives.
I hope this has been helpful!
Laz