Question

5. Explain the steps/Sequence of events (in detail) that would occur if a host has packets destined for:

a) A local address included in the “host” ARP table

b) A local address not included in the “host” ARP table

c) A address not on the “host” network

Answer 1

(a)

Since local address is included in the host ARP table, host can directly resolve MAC address and it can send packets directly to local address.

(b)

I local address is not included in the "host" ARP table:

Step 1: "host" sends ARP broadcast message to all the local address which are present in the same network.

Step 2: Each local address validates the packet by looking at IP address present on the ARP packet. I fit matches with their IP address then they respond with their MAC address.

Step 3: After resolving MAC address, Source "host" stores MAC address in its ARP tables for future communications. Then it sends packets to destined local address.

(c)

I address is not on the "host" network:

Step 1: "host" sends ARP broadcast message to all the local address which are present in the same network.

Step 2:If the destined local address is not present in the same network then the packet reaches default gateway/router. Then then the router broadcasts the packet to local addresses in it's network and validates their network ID.

Step 3: Once the MAC is resolved "host" sends packets to destined address.