Comp Sci Internet
HTTP
-Most web pages are written with HTML (hypertext markup language) and interpreted by your browser using this -used for computers to talk to each other. _________ is the language that computers use when they send messages to a server to find a website. In this language a computer uses Get requests which is just get whatever the person is asking for on the computer. The server then sends back all the code for this request. -use _________ to interpret HTML instructions for page formatting -the protocol that your browser uses to access an HTML webpage -Standards for sharing information and communicating between browsers and servers on the Web include this -the protocol for communicating with web servers and transferring web pages and other data back to a browser -Ensures that the identity of the server involved in an interaction can be trusted and that any messages being sent are encrypted and thus secure
HTML
-Most web pages are written with this -is used to format the documents received by the servers in the correct way. They bold certain words, have a link with certain words and do whatever else is needed for the page to properly appear with the text and images -HTTP: HyperText Transfer Protocol—the protocol that your browser uses to access this
Redunant
-There are multiple pathways among the physical connections of the Internet to create __________. Even if one pathway is unavailable, there is still another way to transmit a message from sender to receiver -Given the enormous amount of data traveling around, the Internet needs to be reliable. We have achieved this by building many _________ connections into the physical systems of the Internet. Wherever information is going, there is more than one way to get there, so that if part of the Internet fails, the rest remains connected even if the failed part is in the usual path from one place to another. This increases the Internet's fault tolerance (ability to work around problems). And it also helps the Internet scale (expand) to more devices and people -good for many routers failing but data still being transferred an many devices can be added to the network without affecting traffic
Packet
-When you send a message over the Internet, your computer divides it into small chunks called _______ that it sends individually, each on its own path. A ________ can include any kind of data: text, numbers, lists, etc. Computers, servers, and routers are fairly reliable, but every once in a while a ____________ will be lost, and devices on the Internet need to tolerate these faults -TCP organizes these things -Each _______ of information is sent independently -It is possible that each ______ might take a completely different path to the end host -_________ switching results in a decentralized network
Digital Certificate
-a data file that identifies individuals or organizations online and is comparable to a digital signature -showing your computer that it is a legit website and a secure connection can be made between the two. These are mandated by the government and are important so that a person can browse the internet without fears of being hacked -systems will struggle with new ones of these because there is not enough people who identified this as a legit website
DNS
-has a hierarchy and at the top is the root domain server then that server can find the next part which is the domain and finally that server can find the subdomains of the domain name. This makes it so the domain does not need an enormous list of different domain names to find the correct one. The ______ searches for an IP address for the server that the person wants -The hierarchy of the domain name system simplifies the process of finding the computer with the desired domain name because the __________ servers that help locate domains don't need enormous lists with every host name in the world. Instead, any user's computer only has to know where to find a root domain server (the one that knows where to find the top-level domains such as .org and .edu), and that server knows where to find the domain (like berkeley.edu), and that server knows where its subdomains are (like snap.berkeley.edu), and so on -the hierarchical addressing protocol that is human-readable -Reads from most specific on left to most general on right -converts user-friendly web addresses into IP addresses -useful because names are easier for humans to remember than the IP addresses of frequently visited websites
TCP
-simulates a reliable, long-term connection between two computers by only displaying data once all packets have arrived. When speed is more important than accuracy, people use UDP (User Datagram Protocol), such as for real-time video streaming, where one missed packet doesn't matter much -the protocol that ensures reliable transmission of data -guarantees reliable transmission by breaking messages into packets, keeping track of which packets have been received successfully, resending any that have been lost, and specifying the order for reassembling the data on the other end. This process is what makes the Internet a packet switching network -The computers (including servers) at the two endpoints of a communication run the this that divides up the packets and guarantees reliable transmission -a reliable transmission system that sends and tracks binary sequences of data (ones and zeros) that are split into small packets sent separately
Protocols
-standards for communication -The growth of the Internet has been fueled by open _______, standards that are not owned by a company -Standards for sharing information and communicating between browsers and servers on the Web include HTTP, Simple Mail Transfer _________ (SMTP) and secure sockets layer/transport layer security (SSL/TLS) -Standards for packets and routing include transmission control _______/Internet ________ (TCP/IP) -refers to the defined rules that allow two connection points to talk to each other -A worldwide group of volunteers raft, revise, and publish these
IP Address
-the hierarchical addressing protocol that manages routing of data between computers; we are upgrading from IPv4 to IPv6 for more addresses -The routers at every connection-point on the Internet run this that transmits packets from one of these to another (not caring that sometimes a packet will be lost and not knowing anything about the purpose or meaning of a packet) -Every device on the Internet has a unique one of these (or more than one, if it's a router), like a postal or email address. This specifies how a router handles a request for another one of these -Computers translate those domain names to any of these to locate and send data behind the scenes -When we type in a domain name, the browser queries the domain name system to find the this of the server we want to visit. These are unique numerical addresses assigned to every device on the Internet. Both the domain name syntax and __________ are hierarchical; however unlike domain names, ________ are hierarchical from right to left (most broad on right, more specific on left) -an addressing system that finds paths to distant computers -standard created by the Internet Engineering Task Force which is always required -identifies a physical device using the internet
Link Layer
All Internet devices connect through a physical interface that uses a protocol to manage the connection to the local network. These local protocols are the least abstract because they deal directly with your physical hardware -Examples: You may connect with an Ethernet cable perhaps a WiFi radio antenna inside the case. Both connects computers to a local network router which then connects to an Internet provider. Cell phones use a longer-range cellular connection to a phone carrier
DNS Spoofing
a form of computer security hacking in which corrupt Domain Name System data is introduced into the DNS resolver's cache, causing the name server to return an incorrect IP address. This results in traffic being diverted to the changed IP address which the hacker introduced
Phishing
an attacker sends you an email that appears to be from some official organization (such as your bank) and tricks you into giving information to the attackers (such as your bank password)
DDoS
attack, in which the attacker first uses viruses (or similar self-spreading software) to take control of many (sometimes tens of thousands of) computers around the world. This network of infected computers is called a botnet. The attacker then launches a DoS attack from all of the victim's computers (called zombie computers) at the same time. Besides increasing the number of simultaneous server requests, DDoS makes it harder to determine who is at fault, since the attack seems to come from many innocent people
Key
created by mathematicians in the 1970s. It uses two different keys for encryption and decryption, so sharing the public encryption key doesn't give away the private decryption key. Public key encryption is the primary method of encryption today because of its high level of security
Metadata
data that describes other data
Malware
software designed to infiltrate or damage a computer system without the user's informed consent
IETF
the experts in charge of developing and approving these protocols. ICANN controls the DNS hierarchy and the allocation of IP addresses. The work of the IETF is done largely by email, and anyone with the necessary expertise can join the mailing lists. Decisions are made by consensus (everyone has to agree to a change), never by voting. The idea is that if a proposal is controversial enough to need a vote, then it should be improved until everyone's objections are satisfied. Unlike ICANN, the IETF has been remarkably free from political pressure, even though it, too, has historically been dominated by experts from the United States. The Internet Society (ISOC) is a worldwide nonprofit membership society that anyone can join, for free. It is now officially in charge of the IETF and also conducts education and promotes government policies supporting an open Internet.
Application Layer
the highest level of abstraction because they manage how data is interpreted and displayed to users. These protocols give meaning to the bits sent by lower-level protocols; user and server computers must agree on what the bits mean, and application protocols (like HTTP) offer this -Examples: browsers use HTTP (HyperText Transfer Protocol) to interpret HTML instructions for page formatting. DNS (Domain Name System) converts user-friendly web addresses into IP addresses. Your email inbox may use SMTP (Simple Mail Transfer Protocol) to send and IMAP (Internet Message Access Protocol) to read email.
