Propagation Delay In Networking

Shubham Dhage
2 min readOct 25, 2020

Let’s understand what is the propagation delay in networking.

pc: unsplash

Propagation delay is nothing but the time that it takes for a bit to reach from one end of a link to the other. The delay depends on the distance (D) between the sender and the receiver, and the propagation speed (S) of the wave signal. and the delay is calculated as: D/S.

Some delay in a network arises because a signal requires a small amount of time to travel across a transmission medium. In general, propagation delays are proportional to the distance spanned. Even with long cable runs, a typical LAN used within a single building has a propagation delay under a millisecond.

Although such delays seem irrelevant to a human, a modern computer can execute over one hundred thousand instructions in a millisecond. Thus, a millisecond delay is significant when a set of computers need to coordinate (e.g., in the financial industry, where the exact time a stock order arrives determines whether an order is accepted).

Let us consider that one user in USA and other user is in India(naded) and both of them want to access to the server which is in India(mumbai) then the significance of the propagation delay would be more forwhich user ?

The distance between the user in USA and Mumbai server is approximately 13000 km, on the other hand, the distance between the user in India and Mumbai server is approximately 800 km. Proportion delay is the Ratio of Distance between host and server to the velocity of the signal (data) transmitted. The velocity of the signal depends on the medium used for proportion.
Let us consider the medium as an optical fibre medium so the velocity is approx 300000 km /sec. So it will take 2.67 milliseconds to travel to user in India and approx 43.33 milliseconds to travel to user in the USA. The proportion delay becomes significant with an increase in distance and it is directly proportional to the distance between the host and server.

--

--