Digital Communication TEST 1

What's a protocol?

-A protocol is a set of rules specifying how computers should communicate with each other over a network. *the Internet Protocol which specifies how computers should route information to other computers by attaching addresses onto the data it sends.

Ted Nelson

imagined how computers would transition from being text- based terminals to interactive machines that expanded the mind. He published computer LIB/Dream machines in 1974.

Communications act of 1934

the far-reaching act that established the Federal Communications Commission (FCC) and the federal regulatory structure for U.S. broadcasting -Title (subchapter) I "information services" or Title (subchapter) II "common carrier services"

Cybernetics

the science of communications and automatic control systems in both machines and living things.

FCC and Title II Regulations

•In 2015, FCC reclassified ISPs under Title II, it gave itself the power to treat them as "common carriers." This means that it can supervise their rates and practices, force them to provide service, and ban practices that it decides are "unjust or unreasonable."

Digital Communication

-takes the history of the computer and the history of the internet -contemporary culture and society is shaped by digital technologies IMPORTANT QUESTION: -How do digital technologies of comm affect their users, societal norms, and cultural values. -- race , gender, sexuality, religion, politics, economy , finance.

Net Neutrality

-the principle that all Internet traffic should be treated equally by Internet Service Providers. -the principle that Internet service providers should enable access to all content and applications regardless of the source, and without favoring or blocking particular products or websites.

legal

-who has access over our personal information -how much power do you have over your digital profile (includes the things you search) -do you have a right to be forgotten? -what is the regulatory framework for the internet ?

packet loss

. This typically happens when a router receives more packets it can process. It has no option other than to drop some packets. -However, the Transport Control Protocol handles packet loss by performing re-transmissions. It does this by having the destination computer periodically send acknowledgement packets back to the source computer indicating how much of the message it has received and reconstructed. If the destination computer finds there are missing packets, it sends a request to the source computer asking it to resend the missing packets.

1990's big backbone networks created by government.

1984 gov. gave internet over to commerical companys. - long distance networks, that allow high speed connectivity. carries large amnt of internet traffic.

IP addresses

2 standards: 1.) The first address standard is called IPv4 and it looks like 212.78.1.25 . But because IPv4 supports only 2³² (about 4 billion) possible addresses, the Internet Task Force proposed a new address standard called IPv6, which look like 3ffe:1893:3452:4:345:f345:f345:42fc . 2.) IPv6 supports 2¹²⁸ possible addresses, allowing for much more networked devices, which will be plenty more than the as of 2017 current 8+ billion networked devices on the Internet. *there are public and private IP addresses. Multiple devices on a local network connected to the Internet will share the same public IP address. Within the local network, these devices are differentiated from each other by private IP addresses. -private IP addresses are assigned by Dynamic Host Configuration Protocol (DHCP).

binary digit (bit)

8 bit = 1 byte 1000 byte is 1 kilobyte (kb) 1000kb = 1 megabyte (mb) 1000 mb = 1 gigabyte (gb) 1000 gb is 1 terabyte (tb) ....petabyte, exabyte, zetabyte, yottabyte -transistors: light on / light off -byte as unit of starage and unit processing unit.

3C's

Communication -With the machine and through the machine. Command -when you press a button on the machine it gives it commands Control-

culture

-social media -online gaming -streaming media -smart phone -identity , community, connectivity

Claude Shannon

"the father of information age" -with 1's & 0's we can represent everything that can be formaly represented -boolean logic and base two system -Boolean logic: variables are defined by Truth value: true/false -The mathematical theory of information -war time cryptographer -worked at bell lab after war -how to transfer voice thrrough wires -everything is information -"bit" is the smallest unit of information "it from bit"

Claude Shannon

"the father of information theory/age"

Douglas Engelbart

- interested in using computers for personal use. -invented the computer mouse and keyboard.

The internet architecture (how do we access the internet)

-Decentralized -TCP/IP -WWW -EMAIL -Cables/data centers

Digital Culture (how do we access the internet)

-Digital divide -ubran - broadband- smart cities -rural dial up -Education: inequal digital access

digital economy (how do we access the internet)

-ISPs (internet service providers) -social media -free/immaterial labor -cables (transatlantic cables) -internet companies -telecommunication companies

Binary Logic

-In the world of binary there are only two states: false and true, zero and one. - represent everything else by combining these values together. zero and one are represented by low and high current. -The low signal is just above zero volts (~0.5V) and the high signal is conventionally 5 volts. * These are inputs... (1=True=high) (0=False=low) -When both inputs are True; the output =True "why only 0 and 1? Couldn't you just add another digit?" While some of it comes down to tradition in how computers are built, to add another digit would mean we'd have to distinguish between different levels of current—not just "off" and "on," but also states like "on a little bit" and "on a lot." -binary math is way easier for a computer than anything else. Boolean logic maps easily to binary systems, with True and False being represented by on and off. Gates in your computer operate on boolean logic: they take two inputs and perform an operation on them like AND, OR, XOR, and so on. Two inputs are easy to manage.

how to prevent tracking

-remove yourself from databases -opt out -complain to government organization -browsers that don't allow people to track you like firefox.

symmetric encryption

A symmetric encryption consists of an encryption function that takes a secret key k and a message m, and returns c, a ciphered message. A decryption function that is the inverse of the encryption function for a fixed secret key k.

And logic v. NAND logic

AND =rational thinking or "voting" NAND="not and" the output will be true except when both A and B are true. This is the exact opposite of AND, so we call this logic NAND for "NOT-AND."

SSL Certificate

An SSL certificate is a digital document that consists of a public key assigned to a web server. These SSL certificates are issued to the server by certificate authorities.

encoding

An encoding scheme is a conversion of text to numbers. For example, ASCII is an encoding scheme where A = 65, B = 66, C = 67, etc. With an encoding scheme, every text message has a unique corresponding number, where mathematical functions can be applied.

Asymmetric encryption

Asymmetric encryption is an encryption scheme which uses a public key and a private key. -The private key is used to decrypt data and sign documents. -The public key is used to encrypt data and verify signed documents. Unlike symmetric encryption, asymmetric encryption means the ability to encrypt does not automatically confer the ability to decrypt. It does this by using principles in a mathematical branch called number theory.

link layer

At the lowest level is the Link Layer which is the "physical layer" of the Internet. The Link Layer is concerned with transmitting data bits through some physical medium like fiber-optic cables or wifi radio signals.

understanding binary

Binary is a base 2 number system. Base 2 means there are only two digits—1 and 0—which correspond to the on and off states your computer can understand. You're probably familiar with base 10—the decimal system. Decimal makes use of ten digits that range from 0 to 9, and then wraps around to form two-digit numbers, with each digit being worth ten times more than the last (1, 10, 100, etc.). Binary is similar, with each digit being worth two times more than the last. Volume 0% -The numbers double each other each time 1111 (in binary) = 8 + 4 + 2 + 1 = 15 (in decimal)

What's a packet?

Data sent across the Internet is called a message. -Before a message is sent, it is first split in many fragments called packets. These packets are sent independently of each other. -The typical maximum packet size is between 1000 and 3000 characters. The Internet Protocol specifies how messages should be packetized. -The packets may arrive at their destination out of order. This happens when a later packet finds a quicker path to the destination than an earlier one. But packet's header contains information about the packet's order relative to the entire message. The Transport Control Protocol uses this info for reconstructing the message at the destination.

How does the router now where to send the packet?

Every router does not need to know where every IP address is. It only needs to know which one of its neighbors, called an outbound link, to route each packet to. -Note that IP Addresses can be broken down into two parts, a network prefix and a host identifier. For example, 129.42.13.69 can be broken down into Network Prefix: 129.42Host Identifier: 13.69 A new router may come with a few preconfigured routes. But if it encounters a packet it does not know how to route, it queries one of its neighboring routers. If the neighbor knows how to route the packet, it sends that info back to the requesting router. The requesting router will save this info for future use.

Digital monopoly

Google eliminates competition by buying out all the other companies. ex: youtube; waze

Vulnerabilities

How do we still get hacked???? 1. computer is infected 2. network is infected 3. website you visited is infected ... can happen by -opening an email (phishing) -clicking a link -downloading a third party app - Botnet: email from infected device starts sending millions of emails SPAM. -DDOS attacts: distributed denial of service (the internet of things and new ips) overwhelms system with server.

How do applications communicate over the Internet?

Internet Network Layers consist of Link Layer(layer 1), Internet Layer, Transport Layer, and Application Layer (layer 4). -These are called layers because they are built on top of each other; each layer uses the capabilities of the layers beneath it without worrying about its implementation details.

What's a packet routing network?

It is a network that routes packets from a source computer to a destination computer. -The Internet is made up of a massive network of specialized computers called routers. Each router's job is to know how to move packets along from their source to their destination. -A packet will have moved through multiple routers during its journey. -When a packet moves from one router to the next, it's called a hop.

Transport layer

On top of the Internet Layer is the Transport Layer. This layer is to compensate for the fact that data can be loss in the Internet and Link layers below. The Transport Control Protocol mentioned earlier lives at this layer, and it works primarily to re-assembly packets into their original messages and also re-transmit packets that were loss.

Internet layer

On top of the Link Layer is the Internet Layer. The Internet Layer is concerned with routing packets to their destinations. The Internet Protocol mentioned earlier lives in this layer (hence the same name). The Internet Protocol dynamically adjusts and reroutes packets based on network load or outages. -Note it does not guarantee packets always make it to their destination, it just tries the best it can.

What is SSL/TLS?

SSL stands for Secured Sockets Layer. TLS stands for Transport Layer Security. SSL was first developed by Netscape in 1994 but a later more secure version was devised and renamed TLS. We will refer to them together as SSL/TLS. SSL/TLS is an optional layer that sits between the Transport Layer and the Application Layer. It allows secure Internet communication of sensitive information through encryption and authentication. Encryption means the client can request that the TCP connection to the server be encrypted. This means all messages sent between client and server will be encrypted before breaking it into packets. If hackers intercept these packets, they would not be able to reconstruct the original message. Authentication means the client can trust that the server is who it claims to be. This protects against man-in-the-middle attacks, which is when a malicious party intercepts the connection between client and server to eavesdrop and tamper with their communication.

Application Layer

The Application Layer sits on top. This layer uses all the layers below to handle the complex details of moving the packets across the Internet. It lets applications easily make connections with other applications on the Internet with simple abstractions like sockets. -The HTTP protocol which specifies how web browsers and web servers should interact lives in the Application Layer. -The IMAP protocol which specifies how email clients should retrieve email lives in the Application Layer. The --FTP protocol which specifies a file-transferring protocol between file-downloading clients and file-hosting servers lives in the Application Layer.

how does the internet work?

The Internet works through a packet routing network in accordance with the Internet Protocol (IP), the Transport Control Protocol (TCP) and other protocols. -TCP/IP protocols are used to send/retrieve information from one computer to another. A request is sent over the network, hitting DNS (domain name servers) along the way to find the target server. The DNS points the request in the right direction. Once the target server gets the request, it can send a response back to your computer.

Lev Manovich

The Language of New Media -implications and applications of digital communication -5 principals: 1. numerical representation 2. modularity 3. automation 4. variability 5. transcoding

the client checks

The client checks that the SSL certificate is issued to this server is signed by a trusted certificate authority has not expired.

The internet

The network of computer networks. -a digital space in which computers communicate (or we communicate through computers) (cyberspace) -a digital space where all digital information is stored (dematerialization?) -funded by the goverment ( a research project to combine things) -in 1980's became commercialized -way to connect computers

PACKET SWITCHING extra notes (may or may not help)

The sender will generate data in an application on their computer. This happens at the application layer. The data is split into packets of data. This happens at the transport layer. Internet Protocol adds IP addresses to each packet. This happens at the Internet layer. Packets are grouped into frames and sent to the router on the LAN. This happens at the Network layer. The sender's router inspects the packet to determine if the destination IP is on the current LAN. If it is not then it will send the packet onto the Internet (or other wide area network). This happens at the Internet layer. Each packet is sent from the sender's router to the destination router via connected routers. The path of each packet can be different, which maximises efficient use of the network by avoiding bottlenecks. Because they have taken different paths, the packets at the destination will be in the wrong order. These packets are unpackaged and reassembled into the correct order using the sequence number of each packet.

Telecommunications Competition and Deregulation Act of 1996

Title V: Communications Decency Act: •(2) Civil liability No provider or user of an interactive computer service shall be held liable on account of—(A)any action voluntarily taken in good faith to restrict access to or availability of material that the provider or user considers to be obscene, lewd, lascivious, filthy, excessively violent, harassing, or otherwise objectionable, whether or not such material is constitutionally protected; or •(B)any action taken to enable or make available to information content providers or others the technical means to restrict access to material described in paragraph (1).[1]

Web 2.0

a new way of using the internet for collaboration and sharing of data among individual users

How do networked computers figure out ip addresses based on domain names?

We call looking up the IP address of a human-readable domain name like www.google.com "resolving the IP address". Computers resolve IP addresses through the Domain Name System (DNS), a decentralized database of mappings from domain names to IP addresses.

tcp connection

When two computers are communicating through the Transport Control Protocol, we say there is a TCP connection between them.

What's a client versus a server?

While clients and servers are both applications that communicate over the Internet, clients are "closer to the user" in that they are more user-facing applications like web browsers, email clients, or smart phone apps. Servers are applications running on a remote computer which the client communicates over the Internet when it needs to. -A more formal definition is that the application that initiates a TCP connection is the client, while the application that receives the TCP connection is the server.

computer

any machine that processes, stores, and receives information.

what does a data broker collect?

basically everything

late 1980's Tim Berners

designed world wide web. "The pool of human knowledge" -HTTP, HTML, URL, HYPERLINK

Ip #

digital address of your computer

Big Data

extremely large data sets that may be analyzed computationally to reveal patterns, trends, and associations, especially relating to human behavior and interactions.

Digital

made out of digits -langage of the computer : computer speaks in 1's and 0's ... then everything is converted into pixels.

Packet switching method

packet has 2 parts 1.) Header - contains info that helps packet get to destination, incl. length of packet, source and destination, and checksum value that helps the recipient detect if a packet was damaged in transit. 2.) after the header comes the actual data. a packet that can contain up to 64 kilobytes of data which is roughly 20 pages of plain text.

FCC Chairperson (Obama Administration) Tom wheeler

pro net neutrality

Network Address Translation (NAT) protocol.

protocol of mapping private IP addresses to public IP addresses -It's what makes it possible to support 8+ billion networked devices with only 4 billion possible IPv4 addresses.

Cognitive Surplus

results when leisure time and tools allow us to engage in creative acts