This delay in routers is what we called Packetization delay
or also called Accumulation delay. Packetization delay is the time required for
the information to pass on the wires. The data rate of the links that passes
thru the wires cause the delay.
By the range 56 to 71 it means that for loop will run when i=56 to i=71, but the upper bound is one less than the upper bound, and which is 70. So the above loop will print integers from 56 to 70.
