On an Ethernet network PC1 sends a message to PC2 The messag

On an Ethernet network, PC1 sends a message to PC2. The message must cross two routers along the pathway. Which of the following statements are true concerning the communication between PC1 and PC2?

A. The frame header changes twice during the time it is sent from PC1 to finally reaching its destination at PC2.

B. The frame header changes three times during the time it is sent from PC1 to finally reaching its destination at PC2.

C. The packet header changes at each router in the delivery path.

D. The packet header never changes during the delivery path.

E. PC1 broadcasts a DNS message to determine PC2’s MAC address before building the frame.

F. PC1 broadcasts an ARP request to determine PC2’s MAC address before building the frame.

Solution

C is correct. In CSMA/CD, systems involved in a collision send a jam signal to indicate a collision to all devices. They then run a timer algorithm, allowing them to retransmit at a random time interval.

A, B, and D are incorrect. A is incorrect because only systems involved in the collision send a jam signal. B is incorrect because RTS messages are sent on CSMA/CA, not CSMA/CD. D is incorrect because collisions do occur on CSMA/CD.