Question

Consider two hosts X and Y connected by a single direct link of rate ${10}^6$ bit/sec. The distance between the two hosts is 10,000 km and the propagation speed along the link $2\times {10}^6$ m/sec. Host X sends a file of 50,000 bytes as one large message to host Y continuously. Let the transmission and propagation delays be p milliseconds and q milliseconds, respectively.
Then the values of p and q are

• A. p = 50 and q = 100
• B. p = 5 and q = 400
• C. p = 100 and q =50
• D. p = 400 and q = 50

Answer 1

The correct option is D p = 400 and q = 50

$\text{Transmission time}=\frac{Datasize}{Bandwidth}$
$=\frac{50000\times 8bits}{{10}^6}=400msec$
$\text{Propagation time}=\frac{Distance}{Velocity}$
$=\frac{10000\times {10}^{3}m}{2\times {10}^{8}m/sec}$
$=50\times {10}^{5-8}$ sec
$=50$ msec