TASK 2:Briefly describe the process of sendin packet from host A to host D.

The transmission would go like this:

Host A wants to send a packet to Host D. Host A must knows Host D's IP address. However, if it does not know, then it will send something called an ARP request (Address Resolution Protocol) to the network, with the destination IP. 

 A few things will happen here:

1. If the IP is local. The host with that IP will reply back to the sender with its MAC address.
2. If the IP is non-local. The gateway router will detect this and send its MAC address.
3. If the IP is non-local and Host A's default gateway and subnet mask are set. Using this information Host A can determine the non-locality of the IP address and send it to the router's MAC address (ARPing if not known yet).

If Host A found this out earlier, it will be in the ARP cache and Host A will just use that. Now that the MAC address is sent, the packet can be transferred. The next stop will be the switch. The switch knows which outbound port the MAC address listed as the destination is on, because it tracks every MAC address it's seen a packet come from and which port it came on, If it does not know, then it will flood it out every single port, guaranteeing it'll arrive.

As such, the packet arrives at the router. The IP model is that it divides every single IP address in the network/world into a hierarchy which is subnet. The packet is then sent out that port.