Numerical question on cn


#1

Suppose ‘A’ and ‘B’ are on same 10Mbps Ethernet segment and the propagation delay between two nodes is 275 bit times. Suppose A and B are on two ends of the wire and tries to send a frame at time t=0 and frames collide. Then at what time (in bits) they finish transmitting a jam signal. Assume 48 bit jam signal.
A. 598 B. 323 C. 502 D. 227


#2

The correct answer is 323.
Since A and B are sending frames at the same time , so the collision will occur in between the wire so the distance will be half of 275 = 137.5
And the collision will produce a signal which will traverse back to A and B, again it will take 137.5 bit times.
After this a jamming signal will be produced which is 48 bits
So total time till they finish with jamming signal is the time till the signal is produced= 137.5+137.5+48
=323