Example: Two terminals A and B want to communicate using virtual packet switching. The network has one intermediate node with equal distance from terminals. Find the message delivery time if message size $($L$)=8000$ bits, header size $($H$)=24$ bytes, packet size $=800$ bits, link rate $($c$)=80$ kbps$,$ propagation speed $($s$)=100$km $/$ s and distance between A and B $=30$km Assume negligible node delay.

Solution:

Given L $=8000$ bits

H$=24$X$8=192$ bits

packet size $=800$ bits

link rate, C $=80$ kbps Propagation speed, S $=100$km $/$ s

No$.$ of packets $=8000/800=10$

Total delivery time $=3$ Tp $+2$ Tp$+11$ Ts$=1\mathrm{.}31$ sec

Tp $=30/100=0\mathrm{.}3$ sec

T $*$ p$\text{'}=15/100=0\mathrm{.}15$ sec

Ts $=800/80000=0\mathrm{.}01$ sec