How to Avoid Colliding Signals In a Transmission Cable

Question

Suppose two nodes, A and B, are attached to opposite ends of an 800 m cable, and that they each have one frame of 1024 bits (including all headers and preambles) to send to each other. Both nodes attempt to transmit at time t = 0. Suppose there are five repeaters between A and B, each inserting a 20-bit delay. Assume the transmission rate is 10 Mbps, and CSMA/CD with backoff intervals of multiples of 512 bits is used. After the first collision, A draws K = 0 and B draws K = 1 in the exponential backoff protocol after sending the 48-bit jam signal.

a. What is the one-way propagation delay (including repeater delays) between A and B in seconds? Assume that the signal propagation speed is 2*10^8 m/sec.

b. At what time (in seconds) is A's packet completely delivered at B?

c. Now suppose that only A has a packet to send, and that the repeaters are replaced with switches. Suppose that each switch has a 16-bit processing delay in addition to a store-and-forward delay. At what time, in seconds, is A's packet delivered at B?

Note: you must include all the delays occurred according to CSMA/CD protocol.

Summary

The question belongs to Computer Science and particularly to Networking. The question here is about colliding signals in a cable and the methods used to rectify errors caused by this and to transmit information correctly.

Total Word Count 83