# What exactly is transmission time?

Seems very trivial but I'm confused which one of these correctly define transmission time.

• Time taken by a message to reach receiver.

• Time taken to push message on the link by the sender.

Which one is correct one?

Packet transmission time = Packet size / Bit rate

• Or Propagation time is time to reach destination by $1$st bit? – Mr. Sigma. Dec 4 '18 at 4:26