Lecture 11: Networking Background

Intro to Networking


Local Area Networks (LANs)

Wide Area Networks

MAC Addresses

The Internet

(True/False) In the diagram where Host A passes a message through 3 routers to communicate with Host D, Host A and Host D are on the same local network.

IP Addresses

(True/False) A machine can have both a MAC address and an IP address at the same time.


Can a single message make multiple hops across different technologies (wireless/wired) as it travels across the global network?


Headers with Multiple Layers

Which part(s) of the packet does the IP protocol see as the header? Which part(s) does the IP protocol see as the payload? Which part(s) does the IP not see at all, and why?

Dumb Network

Which of the three layers we've seen so far are implemented hop-by-hop, and which are implemented end-to-end?

Best Effort Delivery

TCP Bytestreams


TCP Sequence Numbers

TCP Handshake



Optional Bonus

This optional bonus video shows how all the networking protocols interact when you visit a website. (Note: It includes some protocols we haven’t covered yet.)