Question

What is the total delay (latency) for a frame of size 5 million bits that is being sent on a link with 10 routers each having a queuing time of 2 μs and a processing time of 1 μs. The length of the link is 2000 km, The speed of light inside the link is 2 x 108 m/s, the link has a bandwidth of 5 Mbps. Which component of the total delay is dominant? Which one is negligible? useAPA referencing style for all cited material you have used in your work. All your work must be cited.

Answer 1

from the question the various component is given:-

length of link (Distance)=2000 Km = 2*10^6 m

speed of light inside the link (propagation speed) = 2*10^8 m/s

Propagation time = distance divided by propagation speed

Propagation time = (2* 10^6)/(2* 10^8) sec= 0.01 sec

now given message size or frame size= 5 million = 5 *10^6 bits

bandwidth = 5 mbps= 5 * 10 ^6 bps

so Transmission time = Message size divided by Bandwidth

Transmission time = (5 * 10 ^6)/(5 * 10^6) sec= 1 sec

no. of router is used =10

queuing time for each router is =2  μs

so queuing time for 10 router = 10 * 2  μs = 20  μs =0.000020 sec

now for processing time

processing time for each router is = 1 μs.

so processing time for 10 router = 10 * 1μs.= 10 μs.= 0.000010 sec

now calculation of total delay

total delay = sum of processing time, queuing time, transmission time and  Propagation time

total delay =   0.01 sec + 1 sec + 0.000020 sec + 0.000010 sec= 1.010030 sec

Which component of the total delay is dominant?

ans:-  Transmission time

Which one is negligible

ans:-  processing time