Propagation delay is the time taken for a packet to reach from sender to receiver. It is given by Tp = d/v, where is d is the total distance covered by the packet and v is the speed of transmission. Time taken to place a packet on the outgoing link is known as transmission time. It is given by Tt = L / B, where L is the length of the packet and B is the bandwidth of the transmission medium using which the packet is being transmitted. Efficiency depends on both propagation delay and transmission time, thereby depending on length of packet, bandwidth of link, distance traveled by packet and speed of transmission. This video highlights this dependency with the help of a concrete example.
For more videos on Networking check out the following links
Numerical on SAW Efficiency
https://www.youtube.com/watch?v=yvkgofuq1JY&list=PLupEg_4X8NV3cGPepFKQGvtO4soN8OpDi&index=3&t=0s
Computer Networking MCQs
https://www.youtube.com/watch?v=79QRw7mHIlE&list=PLupEg_4X8NV3cGPepFKQGvtO4soN8OpDi&index=3
IP Datagram Format
https://www.youtube.com/watch?v=I6tnLJqO01Y&list=PLupEg_4X8NV3cGPepFKQGvtO4soN8OpDi&index=1
