Solution

The correct answer is Option 2

Key Points

• Transmission Delay (t_tx): Time taken to push all bits of the frame onto the medium.
• Propagation Delay (t_prop): Time taken for the first bit to travel from the sender to the receiver through the medium.
• Formulae:
  • t_tx = (Frame size in bits) / (Data rate in bps)
  • t_prop = (Distance) / (Propagation speed)

Step-by-Step Calculation:

1. Transmission Delay:
   Frame size = 512 bits, Data rate = 10 Mbps
   t_tx = 512 / (10 × 10⁶)
   = 51.2 × 10^-6 sec = 51.2 μs
2. Propagation Delay:
   Distance = 2500 m, Propagation speed = 2 × 10⁸ m/s
   t_prop = 2500 / (2 × 10⁸)
   = 1.25 × 10^-5 sec = 12.5 μs

Options Analysis:

• Option 1: 25.25 μs and 51.2 μs – Incorrect
• Option 2: 51.2 μs and 12.5 μs – Correct
• Option 3: 10.24 μs and 50.12 μs – Incorrect
• Option 4: 12.5 μs and 51.2 μs – Incorrect

Additional Information

• Transmission delay depends only on the frame size and bandwidth, while propagation delay depends only on the distance and propagation speed.
• In high-speed networks with long cables, propagation delay can become comparable to or even exceed the transmission delay for small frames.