What is the Internet? Flashcards
Internet
collection of thousands of individual networks and organizations, each of which is run and paid for on its own
runs on client/server model of information delivery
5 groups that guide the Internet’s growth
- Internet Society
- InterNIC
- Internet Architecture Board (IAB)
- Internet Engineering Task Force (IETF)
- World Wide Web Consortium (W3C)
Internet Society
* Internet Society- non-profit, supports Internet Architecture Board (IAB)
InterNIC
* InterNIC- and other registrars are responsible for maintaining the domains registered through registries; tracks the connections between Internet addresses
Internet Architecture Board (IAB)
* Internet Architecture Board (IAB)- handles Internet’s behind the scenes and architectural issues
Internet Engineering Task Force (IETF)
* Internet Engineering Task Force (IETF)- responsible for overseeing how the Internet’s TCP/IP protocols evolve
World Wide Web Consortium (W3C)
* World Wide Web Consortium (W3C)- develops standards for the evolution of the WWW; industry consortium run by MIT
Registrars
Private companies that oversee registration of Internet domains
Individual local networks
can be found in private companies, universities, government agencies, online services
ISPs
Internet service providers (ISPs) have networks, sell people monthly connections to the Internet. They run their own segments of the Internet and might supply long-distance connections called backbones.
Regional networks
Local networks join in consortiums known as regional networks- regional networks provide and maintain Internet access within a geographic area. Can consist of smaller networks and organizations within the area that have banded together to provide better service
Backbones
* Private companies who make money by selling access to their lines build backbones which are high-capacity lines that carry enormous amounts of Internet traffic
* NASA and the NSF also pay for some backbones
client
typically local personal computer or software that runs on it
server
(also known as host)- more powerful computer that houses the data/server software
HTTP
hypertext transfer protocol, the protocol used by the World Wide Web
DNS
Domain Name System, the way in which computers contact each other
When someone on Internet wants to visit website, types in address via URL. DNS translates the address into an IP address, which marks the locatin of a computer on the Internet similar to an address
Major domain
letters at the end of the address: .com, .edu. gov
name servers
computers responsible for keeping track of changes in IP addresses and translating them between IP addresses and domain addresses.
name servers contain tables that match alphanumeric Internet addresses to numeric IP addresses
Standard vs. dynamic IP address
IP= internet protocol
many ISPs use dynamic IP addresses because of limited number of IP addresses
URL
Uniform Resource Locator
DHCPDISCOVER & DHCPOFFER
To obtain dynamic IP address, computer sends a broadcast message called DHCPDISCOVER packet to network or ISP
Received by DHCP server, which checks list of available IP addresses
DHCP server broadcasts response called DHCPOFFER packet
NAT
Network Address Translation
used to resolve problem of not enough IP addresses and protects PCs inside a network.
each router has its own IP address, assigned by ISP. This is visible on Internet.
Each PC on home network gets an internal IP adress from the router and is used only for communications within the network itself, and is not visible to the outside world
When the PC browses the Internet, it appears to have the routers IP
