James F. Kurose, Keith W. Ross

Problems

Computer Networks And The Internet

6

9780132856201

10

Consider
a packet of length *L
*which
begins at end system A and travels over three links to a destination
end system. These three links are connected by two packet switches.
Let *di,
si, *and
*Ri
*denote
the length, propagation speed, and the transmission rate of link *i,
*for
*i
*=
1, 2, 3. The packet switch delays each packet by *d*_{proc}*.
*Assuming
no queuing delays, in terms of *di,
si, Ri, *(*I
*=
1,2,3), and *L,
*what
is the total end-to-end delay for the packet? Suppose now the packet
is 1,500 bytes, the propagation speed on all three links is 2.5 ·
108 m/s, the transmission rates of all three links are 2 Mbps, the
packet switch processing delay is 3 msec, the length of the first
link is 5,000 km, the length of the second link is 4,000 km, and the
length of the last link is 1,000 km. For these values, what is the
end-to-end delay?

Therefore, the end-to-end delay =0.064 seconds