Question

- How long does it take a packet of length 1,000 bytes to propagate over a link of distance 2,500 km, propagation speed 2.5 *10^8 m/s, and transmission rate 2 Mbps? More generally, how long does it take a packet of length L to propagate over a link of distance d, propagation speed s, and transmission rate R bps? Does this delay depend on packet length? Does this delay depend on transmission rate?

Answer 1

Answer:

It will take 0.01 s or 10 ms

Solution:

As per the question:

Length of the packet, L = 1,000 bytes = $1000\times 8 = 8000 bits$

Distance, d = 2500 km = $2.5\times 10^{6}\ m$

Speed of propagation, s = $2.5\times 10^{8}\ m/s$

Transmission rate, R = 2 Mbps

Now,

Propagation time, t can be calculated as:

$t = \frac{d}{s} = \frac{2.5\times 10^{6}}{2.5\times 10^{8}} = 0.01\ s$

t = 10 ms

• In general, propagation time, t is given by:

       $t = \frac{link\ distance}{Propagation\ speed}$

• No, this delay is independent of the length of the packet.
• No, this delay is independent of the rate of transmission.