Question

29. Consider the following LAN with one Ether switch S, one intra-domain router R, and two hosts X and Y Assume switch S has been just powered on. 1. Describe the routing and address resolution steps performed at X, Y, and S when X sends an IP packet to Y. 2. Describe the routing and address resolution steps performed at X, Y, and S when Y replies an IP packet to X. 3. Describe the routing and address resolution steps performed at X, S, and R when X sends an IP packet to a host that is outside the domain. (Hint Do not forget to explain how X knows of the router R.) Ethernet Ethernet

Answer 1

29.

1) Solution For the given figure X and Y are not in the same IP subnet such that the packet has sent to router R forinter domain routing . Address Resolution Protocol is used to find the Mac address of Y then it will process to the IP address If the Host X has broadcast the message an ARP request message to all host within the subnet When host Y can be recognized to the destination IP address then it will matches to the own IP address Therefore it will send ARP reply to the unicast message ofhost X After that successful round of ARP finally host X and Y will has update the cache table of two pairs Mac and IP address .

2) Solution After destination IP address thenit will checked against to the cache memorytable The MAC address has correspond to the host X IP address is found .Therefore IP packet is send directly to the Ethemet switch S then it will forwarded to X '