A3. Computing end-end delay (Transmission and Propagation delay) Consider the fi
ID: 3748548 • Letter: A
Question
A3. Computing end-end delay (Transmission and Propagation delay) Consider the figure below, with three links, each with the specified transmission rate and link length. Link 1- Link 2Link 3 Transmission rate: 100 Mbps Link Length: 2 Km Transmission rate: 100 Mbps Link Length: 3 Km Transmission rate: 1 Mbps Link Length: 5000 Km Find the end-to-end delay (including the transmission delays and propagation delays on each of the three links, but ignoring queueing delays and processing delays) from when the left host begins transmitting the first bit of a packet to the time when the last bit of that packet is received at the server at the right. The speed of light propagation delay on each link is 3x10'8 m/sec. Note that the transmission rates are in Mbps and the link distances are in Km. Assume a packet length of 8000 bits. Give your answer in milliseconds.Explanation / Answer
Total delay = Sum of transmission delay and propagation delay for each link
Transmission delay = packet size/transmission rate
Prop delay = link length/speed of light
In link 1
Transmission delay = 8000/(100*10^6) = 8x10^-5 s
Prop delay = 2000/(3*10^8) = 6.666x10^-6
In link 2
Transmission delay = 8000/(10^6) = 8x10^-3
Prop delay = 5000x10^3/(3*10^8) = 1.66x10^-2
In link 3
Transmission delay = 8000/(100*10^6) = 8x10^-5 s
Prop delay = 3000/(3*10^8) = 1x10^-5s
Total delay = Sum of all the above = 0.024766s = 24.766ms (rounded off)
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