Difference between Propagation Time and Propagation Delay

Question

I have found several answers to Propagation Delay but none come up when we talk about Propagation time. Are they the same thing?

Propagation Delay:

propagation delay is the amount of time it takes for the head of the signal to travel from the sender to the receiver. wiki

Answer 1

i am not sure but propagation time should be the propagation delay plus the time to generate the bit at the sender and store the bit at the receiver.

Answer 2

propagation time and delay are identical. It is clear to the definition provided. When it says head of the signal or packet, it means it is already loaded on the line. So delay or time of storing and retrieving packets to/from the line in not calculated in propagation time/delay. Hence, IMHO they are exactly the same.

Answer 3

Yes, they both are same... In fact in networks we more often use propagation delay instead of propagation time... and what we think that the propagation time is equal to propagation delay + info. Loading and retrieving time is not correct as the later one is defined as the transmission time... It's exact definition is given as:

"In a network based on packet switching, transmission delay (or store-and-forward delay, also known as packetization delay) is the amount of time required to push all the packet's bits into the wire. In other words, this is the delay caused by the data-rate of the link."