Question

What is the minimum link delay for a 2.5MB packet sent from Jacksonville to New York (1000 miles) over a 100Mbps fiber link

Answer 1

Packet Size (L)= 2.5 MB = 2. 5 x 2²⁰ x 8 bits

Distance (D) = 1000 miles = 1000 X 1609.34 = 1609.34 x 10³ meters.

Velocity of fiber link (V) = 70% of speed of light = 0.7 x 3 x 10⁸ = 2.1 x 10⁸ m/s

Bandwidth (B) = 100 Mbps = 100 x 2²⁰ bps

Link Delay = Propagation Delay (D/V) + Transmission delay (L/B)

Link Delay = (1609.34 x 10³ / 2.1 x 10⁸ ) + ((2. 5 x 2²⁰ x 8 )/ (100 x 2²⁰ )) = (0.0076) + (0.2) seconds = 0.2076 sec

Link Delay = 0.2076 seconds or 207.6 milli seconds.