79 terms

ISDS 1100

Who owns the Internet?
Individuals, Universities, Government Agencies, Private companies
Who manages the Internet?
Nonprofit organizations, user groups
Who pays for the Internet?
U.S. taxpayers, businesses, universities, other countries
Point of Presence (POP)
WAN (Wide Area Network) connection point used to obtain access to the WAN.
-Can we wired or wireless
Internet Backbone
Collection of large national and international networks.
-T lines: initially used for backbone ISP connections.
-Carried digital data over tiwsted-pair wires
Optical carrier line (OC)
Today's most common backbone ISP connection.
-High speed, fiber optic lines designed to provide high throughput.
In the past, points of connection between ISPS
were once known as network acces points (NAPs).
-Designed to move large amounts of data among networks.
private sector companies make up the Internet system.
-Exchange data via Internet exchange points (IXPs). Typical IXP is made up of one or more network switches.
Point of Presense (POP)
which is a bank of modems, servers, routers, and switches through which many users can connect to an ISP simultaneously.
-ISPs maintain multiple POPs throughout the geographic area they serve.
Internet communications follow the clinet/server network model
Clients request services
Servers respond to the client requests
Web servers
run specialized operating systems that enable them to host Web pages and provide requested Web pages to clients.
Commerce servers
host software that enables users to purchase goods and services over the Web. These servers generally use special security protocols to protect sensitive information (such as credit card numbers) from being intercepted.
File servers
deployed to provide remote storage space or to act as a repository for files that user s can download.
Uses cables, radio waves, or infrared signals. Links computers in a limited geographic area.
Uses long-distance transmission media. Links computer systems a few miles or thousands of miles. Internet is the largest WAN.
Dwesigned for a city. Larger than a LAN, smaller than a WAN
Several LANS located in various locations on a college or business campus. Smaller than a Wan. Uses devices such as switches, hubs, and routers.
Network of an individual's own personal devices. Usually within a range or 32 feet. Usually use wireless technology.
joins multiple computers together in a single network. Does not manage traffic between the conections.
Filters and forward data between nodes. Are similar to routers but work within a single network.
Connect 2 or more networks. Inspect the source and target of a data package. Determine the best route to transmit data.
Advantages of Networking
- Reduced hardware costs
Application sharing
Sharing information resources
Data management centralization
Connecting people
Disadvantages of Networking
Loss of autonomy
Lack of privacy
Security threats
Loss of productivity
Peer-to-Peer (P2P) Sharing
Ex: BitTorrent. Requires the user to act as both a client and a server. When requeseting files from another user, the computer behaves like a client. It switches to server mode when it provides a file stored on its hard drive to another computer.
Computer protocols
rules for electroninc information exchangee.
Open system protocols
meaning that their designs would be made public for access by any interested party
Proprietary system (private system protocols)
opposite of open system. It was the norm at the time of early internet.
Packet switching
the communications methodology that makes computer communication efficient.
-doesn't require that a dedicated communications circuit be maintained.
-data is broken into smaller chunks (called packets or a data packet) that are sent over various routes at the same time.
-When the packets reach their destination, they are reassembled by the receiving computer.
All packets must contain
(1) an address to which the packet is being sent, (2) the address from which the packet originates, (3) reassembling instructions if the original data was split between packets, and (4) the data that is being transmitted.
Transmision Control Protocol (TCP)
Prepares data for transmission, provides error checking, and enables resending lost data.
Internet Protocol
Responsible for sending data from one computer to another.
Suite of interrelated protocols
Ex: User Datagram Protocol (UDP), File Transfer Protocol (FTP), Telent, HyperText Transfer Protocol (HTTP), HTTP Secure (HTTPS), and Simple Mail Transfer Protocol (SMTP).
Each computer, server, or device connected to the Internet is required to have a unique identification number that defines it.
This is called
IP Address. Ex: (
Static address
Address never changes; most likely assigned manually by a network administrator or ISP.
Dynamic addressing
computer is assigned a temporary address from an avaialbe pool of IP addresses.
When IPv4 didn't see explosive growth and had to fix the problem of the growing Internet, they developed the
Classless interdomain routing (CIDR) or supernetting.
allows a single IP address to represent several unique IP addresses by adding a network prefix (a slash and a number). This identifies how many of the possible 32 bits in a traditional IP address are to be used as the unique identifier, leaving the remaining bits to identifiy the specific host.
addressing scheme that makes IP addresses longer, therefby providign more available addresses. uses 8 groups of 16 bit numbers, reffered to as hexadecimal notation (or hex for short).
-Companies are starting to replace their equipment with this.
Domain name
simply a name that takes the place of an IP address, making it easier for people to remember. For example, www.mywebsite.com is a domain name
Domains are organized by level. The portion of the domain name farthest to the right (after the dot)
top-level domain (TLD). TLDS (such as .com and .org) are standaraized pools established by ICANN. Amazon.com, Google.com, and Microsoft.com
Within the top-level domains are many second-level domains
Each of the second-level domains needs to be unique within that particular domain, but not necessarily unique to all top-level domains. For example, Mycoolsite.com and Mycoolsite.org could be registered as separate domain names.
When you enter the URL, your computer must convert it to an IP address. To do this, your computer consults a database maintained on a
DNS (Domain Name System) server. This functions like a phone book for the internet.
Your ISP's Web server has a default DNS server that it goes to when it needs to translate a
URL to an IP address. If it can't find it, it contacts one of the thirteen root DNS servers maintained throughout the Internet.
Root DNS server
know the location of all the DNS servers that contain the master listings for an entire TLD. Your default DNS receives the information from the master DNS (say, for the .com domain), stores that information in its cache for future use, and communicates the appropriate IP address to your computer.
File Transfer Protocol (FTP)
enables users to share files that reside on local computers with remote computers. If you're attempting to download files using FTP to your local computer, the FTP client program first establishes a TCP session with the remote computer.
both a protocol for connecting to a remote computer and a TCP/IP service that runs on a remote computer to make it accessible to other computers. Telnet enables you to take control of a remote computer (the server) with your computer (the client) and manipulate files and data on the server as if you were sitting in front of that server.
HyperText Transfer Protocol (HTTP)
created especially for the transfer of hypertext documents across the Internet.
HyperText Tranfser Protocol Secure (HTTPS)
extension to the HTTP protocol that ensures data is sent securely over the web.
Transport Layer Security (TLS) and Secure Sockets Layer (SSL)
protect the integrity of data and security of transmissions over the Internet.
HyperText Markup Language (HTML) or Extensible HyperText Markup Language (XHTML).
A Web page is a text document that is formatted using this.
Although XHTML is the development environment of choice for Web developers today, many people still refer to Web site formatting as
"HTML tagging"
HTML/XHTML are not programming languages; rather, they are
sets of rules for marking up blocks of text so that a browers knows how to display them.
Extensible Markup Language (XML)
allows users to build their own markup languages to accommodate particular data formats and needs, instead of being locked into standard tags and formats. Ex: Mathemathical Markup Language (MathML)
Wireless Markup Language (WML)
uses XML to output Web resources on mobile devices.
Common Gateway Interfect (CGI)
provides a methodology by which your browser can request that a program file be executed (or run) instead of just being delivered to the browser. This enables functionality beyond the simple display of information.
CGI files can be created in almost any programming language. The programs created are often referred to as
CGI scripts
CGI scripts accomplish tasks like
creating a guest book or other form on a Web page.
combination of technologies—HTML/XHTML, cascading style sheets, and JavaScript—used to create lively and interactive Web sites.
DHTML technologies
allows a Web page to change in response to user action
-Brings special effects to otherwise static Web pages
AJAX (Asynchronous JavaScript and XML)
newer group of technologies that facilitates the creation of Web applications that can update information on the page without requiring a page refresh or leaving the page.
The most commonly used scripting language for creating DHTML effects is
Cascading sytle sheets (CSS)
Statements that define in a single location how to display HTML/XHTML elements
Enable a Web developer to define a style for each HTML/XHTML element
The rule can be applied to as many elements on as many Web pages as needed
Speeds up global changes
External style sheet
there might be a rule that defines the background color for all paragraphs as blue
Embedded style sheet
the rule for background color for paragraphs might be defined as white.
Inline style sheet
the background color might be light pink.
Document Object Model
-Organizes the objects and elements of a Web page
-Defines every item on a Web page as an object
-Developers can easily change the properties of these objects
Client-side application
computer program that runs on the client and requires no interaction with a Web server. Client-side applications are fast and efficient because they run at your desktop and don't depend on data going back and forth to the Web server.
Two types:
--The first involves embedding programming language code directly within the HTML/XHTML code of a Web page using an HTML/XHTML embedded scripting language.
--The second type of client-side application is an applet, a small program that resides on a server. When requested, a compiled version of the program is downloaded to the client computer and run there.
The Simple Mail Transfer Protocol (SMTP) is responsible for
sending email along the Internet to its destination.
The Multipurpose Internet Mail Extensions (MIME) specification was introduced in 1991 to
simplify adding attachements to email messages. All email client software now uses this protocol for attaching files.
process of coding your e-mail so that only the person with the key to the code (the intended recipient) can decode (or decipher) and read the message. There are two basic types of encryption: private-key and public-key.
Private key encryption
only the two parties involved in sending the message have the code. The main problem with private-key encryption is key security. If someone steals a copy of the code, the code is broken.
Public key encryption
two keys, known as a key pair, are created. You use one key for coding and the other for decoding. The key for coding is generally distributed as a public key. You can place this key on your Web site, for instance. Anyone wishing to send you a message codes it using your public key. When you receive the message, you use your private key to decode it. You are the only one who ever possesses the private key, and therefore it is very secure.
Using encryption doesn't always solve the other problems associated with e-mail. Companies have developed ___which works outside SMTP mail servers.
secure data transmittion software (SafeMessage)
Client server programs for real-time, text based conversations include
IM programs like AOL instant messanger, icq, yahoo messanger, windows live messanger.
Instant messaging has low level encryption, so
sensitive messages should not be sent.
Voice over Internet Protocol (VoIP)
Allows inexpensive or free long-distance phone calls over the Internet
-Some cell phones are VoIP enabled
-Uses packet switching
(the transmission lines are used only when the two computers are communicating, thus allowing the computers to accept and process other information.)
Cloud Computing
refers to using the Internet to deliver business services online that were previously delivered locally by company-owned IT departments. Many Web 2.0 applications (such as blogs, wikis, and social networks) and Web-based e-mail (such as Yahoo! or Gmail) are provided via cloud computing.
Who uses cloud computing?
Businesses that need to process large amounts of data only once in a while can reduce costs by using.
Business that can rent computing power at specific times use this (seasonal businesses).
What is a concern with cloud computing?
SECURITY. Running your own IT department requires careful consideration of how to protect and safeguard data. When you turn over processing to a third party, it's important to carefully investigate the security and backup capabilities of the cloud computing service provider to determine if their procedures meet your requirements for data security.