Week 1 Notes



Hi! Here are the Week 1 Notes, specifically Lecture 2 (Thursday), both as a PDF and directly pasted on the page below. Hopefully this works.

I&C SCI 3 Notes Week 1 Lecture 2

●	What is the Internet?

- The Internet is a global network of interconnected, or networked, computational systems communicating over a set of shared standards, procedures, and formats.

please refer to "The Internet" image for a visual representation



●	4 Nodes:

UCLA - SIGMA 7 SRI - 940

UCSB - 360 UTAH - PDP 10

The 4 nodes are some of the first computers to connect to each other over a network (1969). This project is also known as ARPANET.

please refer to the "ARPA" image for a visual representation



●	Network Control Protocol

-	An NCP is a simplex protocol - messages only move in one direction.

-	NCP eventually formed the basis for the “universal language” that enabled ARPANET to grow.

●	Transmission Control Protocol

-	A TCP is a “duplex” protocol - messages move in both directions.

-	TCP was divided into 2 layers known as TCP and IP (Internet Protocol)

-	TCP handles transmission and transport while IP handles routing and that data is sent to the right destination.

●	Next Nodes:

More NETS were created around the world which were all interconnected to each other

-	MIT, Bolt, TRC, SDC, Harvard, Lincoln Lab, Stanford, UIUC, CWRU, CMU, NASA were all nodes added to the system after the initial 4 nodes

●	Transition

-	January 1st, ARPANET completely transitioned from NCP to TCP

-  TCP/IP makes it very possible to fake identity as a different computer or device

-  Security is a huge issue

-  Data has to go from node 1 → 2 → 3 so node 2 could block or interfere on its way through the network

-	The transition signaled the beginning of the internet as we know it today

-	ARPANET was officially decommissioned two years later as new and existing NETS formed the backbone of the Internet.

●	Security

-	TCP and IP are inherently open making it easy to spoof or falsify info.

-	This problem with connecting everything gives security issues

-	The military’s use of ARPANET was split off to create MILNET

-	Concerns arose over civilian access to military systems through a shared network

-	“The issue of computer security is going to grow”

●	Staying Secure

-	Secure Protocols

-	SSL/TLS

-	IPSec

-	DTLS

-	SSH, WireGuard, Others

Please refer to "Internet VPN Visualizer" for a visual representation



-   BBS (bulletin board system) -The grassroots of the internet, people would go onto the same site and use it as a chatroom/ post things -   Usenet, similar to BBS but it was used as a forum or newsgroup -Built on NNTP (Network news transfer protocol) -Started with MUDs and BBS but transitioned to local client interfaces -   Online communities grew steadily from the 1960s through the 1990s -   The virtual frontier was largely self-governed but had a technical barrier that filtered out some of the generalized population

Summary of Student Responses to Socrative Questions:

1)	What is the Internet?

a.	A network of networks

b.	A public, virtual, entity where people can talk, shop, research, or do pretty much anything imaginable

2)	Why do you like using the Internet?

a.	Convenience

b.	Ability to talk with friends and family

c.	Shopping

d.	Entertainment (TV, movies, YouTube)

e.	Learn how to do things (tutorials)

3)	What are some potential concerns about the Internet?

a.	Lack of privacy

b.	Lack of security

c.	Companies sell your information

d.	Identity theft

e.	Artificial Intelligence (AI) will change the landscape of work and make some jobs obsolete

Summary of Activities:

1)	Activity: a student from each "node" stood up and spun in a circle

i.	Spinning in a circle represents a certain idea (maybe the letter "a") and allows computers to communicate with each other

ii. Other actions that represent ideas might include: raising an arm, raising two arms, clapping, snapping, etc.

iii. Without a common language, each computer might use its own language and not be able to communicate with other computers

iv. Therefore, developing a common computer language is vital