Chapter 13

Who owns the Internet?
Individuals, universities, government agencies, and private companies
Who manages the Internet?
Several nonprofit organizations and user groups
Who pays for the Internet?
The National Science Foundation (NSF) which is a U.S. government funded agency and federal taxes
Optical Carrier (OC) line
a high-speed fiber-optic line
T line
a communications line that carries digital data over twisted-pair wires
Internet exchange point (IXP)
a way of connecting Internet Service Providers (ISPs) that’s made up of one or more network switches to which the ISPs connect
Point of presence (POP)
a bank of modems, servers, routers, and switches through which Internet users connect to an ISP
Client/server model
a model of network communications where a client device uses browsers to request services from networks that make up the Internet
Web servers
computers that run specialized operating systems, enabling them to host web pages and other information and to provide requested information to clients
Commerce servers
computers that host software that enables users to buy goods and services over the web
-Uses special security protocols to protect sensitive information from being intercepted
File servers
computers that are deployed to provide remote storage space or to act as storehouses for files that users can download
Computer protocol
a set of rules for exchanging electronic information
Open system
a system having the characteristic of being public for access by any interested party
Proprietary system
a system having the characteristic of being closed to public access
Circuit switching
where a dedicated connection is formed between two points and the connection remains active for the duration of the transmission
Packet switching
a communications methodology that makes computer communication efficient; data is broken into smaller chunks called packets
Packet (data packet)
a small segment of data that’s bundled for sending over transmission media. Each packet contains the address of the computer or peripheral device to which it’s being sent
What information does a packet contain?
1. An address to which the packet is being sent
2. The address from where the packets originates
3. Reassembly instructions
4. Data that’s being transmitted
Why do packets take different routes and how do they decide which route to use?
The routers that connect ISPs with each other monitor traffic and decide the most efficient route
TCP/IP
the main suite of protocols used for transmitting data over the Internet
The original two protocols that were developed for the Internet are
Transmission Control Protocol (TCP) and Internet Protocol (IP)
The IP is responsible for what?
Sending the information from one computer to another
Internet Corporation for Assigned Names and Numbers (ICANN)
the organization that registers Internet protocol addresses to ensure they’re unique and haven’t been assigned to other users
dotted decimal number (decimal quad)
an IP address
Octet
a reference to each of the four numbers in a dotted decimal number’s IP address
Internet Protocol Version 4 (IPv4)
the original Internet protocol addressing scheme
Internet cache
a section of the hard drive that stores information that may be needed again
Classless interdomain routing (CIDR)
an Internet addressing scheme that allows a single IP address to represent several unique IP addresses by adding a network prefix to the last octet
Network prefix
represented by a slash and a number to the end of the last octet
Internet Protocol Version 6 (IPv6)
an IP addressing scheme developed by the IETF to make IP addresses longer
Hexadecimal digit
a digit with 16 possible values: 0-9 and A-F
Static addressing
the IP address for a computer never changes and is most likely assigned manually
Dynamic addressing
your computer is assigned a temporary address from an available pool of IP addresses
User Datagram Protocol (UDP)
an Internet protocol that creates data packets across the Internet
Connection-oriented protocol
a protocol for exchanging information that requires 2 computers to exchange control packets before sending packets that contain data
Handshaking
the process of exchanging control packets before exchanging data packets
Three-way handshake
1. Your computer establishes a connection to the ISP and announces it has e-mail to send
2. ISP server responds that it’s ready to receive the email
3. Your computer then acknowledges the ready state of the server and begins to transmit the e-mail
Connectionless protocol
doesn’t require any type of connection to be established or maintained between 2 computers exchanging information
Positive acknowledgment (ACK)
sends back this when Y receives a data packet that it can read from X
Negative acknowledgment (NAK)
If the packets is unreadable Y send this to X
Dynamic Host Configuration Protocol (DHCP)
a protocol for assigning dynamic IP addresses
How are domains organized?
By levels
Second-level domain
domain that’s directly below a top-level domain
Who assigns companies or organizations to mange domain name registration?
ICANN
Domain name system (DNS) server
a server that maintains a database of domain names and converts domain names to IP addresses
root DNS server
a DNS server that contains the master listings for an entire top-level domain