1. This elementary problem begins to explore propagation delay and transmission delay, two central concepts in data networking. Consider two hosts, A and B, connected by a single link of rate R bps....

1. This elementary problem begins to explore propagation delay and transmission delay, two central concepts in data networking. Consider two hosts, A and B, connected by a single link of rate
R
bps. Suppose that the two hosts are separated by
m
meters, and suppose the propagation speed along the link is
s
meters/sec. Host A is to send a packet of size
L
bits to Host B.

a. Express the propagation delay,
d_prop
, in terms of
m
and
s.

b. Determine the transmission time of the packet,
d_trans
, in terms of
L
and
R.

c. Ignoring processing and queuing delays, obtain an expression for the end to-end delay.

d. Suppose Host A begins to transmit the packet at time
t
= 0. At time
t
=
d_trans
, where is the last bit of the packet?

e. Suppose
d_prop

is greater than
d_trans
. At time
t
=
d_trans
, where is the first bit of the packet?

f. Suppose
d_prop

is less than
d_trans
. At time
t
=
d_trans
, where is the first bit of the packet?

g. Suppose
s
= 2.5
 10⁸,
L
= 120 bits, and
R
= 56 kbps. Find the distance
m
so that
d_prop

equals
d_trans
.