CMPTR Chapter 5

Arpanet – Created in 1969 by DODLater, the Arpanet split into the MILNET and what became

the Internet.

The Internet – “Inter-Network”TCP/IP Protocol allows LANs to be Interconnected

router

server

ABC Company LAN

hub

router

server

XYZ Company LAN

hub

InternetInter-Network

TCP/IP – Packet Switched Network

routerrouter

Sender’s e-mail is split into packets

1 2 3 4 5

1

2

3

4

5

Packets may take different routes

If packets arrive out of order, Receiver’s computer reorders them. If any packets get lost, Receiver’s computer request that they are resent.

1

2

3

4

5If one data line goes down, routers will automatically reroute packets along another path.

X

TCP/IP is a Suite of ProtocolsBelow is a few of the protocols within the TCP/IP suite.

TCP – Creates a virtual connection between your computer and the one you are communicating with. This protocol splits your data into packets.

IP – How a packet travel through the Internet. Each computer has an IP address. We are using IPv4. IPv6 is an improvement, but will need widespread adoption.

DNS – Allows you to access computers by a friendly name (e.g. myspace.com) instead of its IP address (e.g. 216.78.32.48).

HTTP and HTTPS – Hypertext Transfer Protocol allows you to open web pages.

SMTP – Simple Mail Transfer Protocol allows you to send e-mail.

FTP – File Transfer Protocol allows two computers to exchange files.

VOIP – Voice Over Internet Protocol allows telephone conversations.

New protocols are being added all the time such as BitTorrent which allows for peer-to-peer file sharing.

Want to see more? http://en.wikipedia.org/wiki/Internet_protocol_suite

What makes up the Internet?Users – There’s now over 1 billion Internet users.

Infrastructure Companies – All the companies thatprovide the data lines and routers.

ISP’s – Internet Service Providers give you accessto the Internet. Examples are SBC/Yahoo, Comcast,AOL, Verizon.

Content Providers – Supply the content on the Internet. Any person or company that creates a web site is a content provider.

ASP’s – Application Service Providers provide access to applications over the Internet.

Hardware and Software Companies – Supply the computers, communication software, web browsers, e-mail programs, etc.

Organizations and Government – Various organizations such as the Internet Engineering Task Force (IETF) develop the protocols. Governments may impose restrictions.

Types of Internet ConnectionsDial-up - uses a modem to convert your computer’s digital signal to sound fortransmission over telephone wires. This was the most popular Internet connectionin the 1990’s, but is This is the oldest and slowest (56Kb/sec)connection type. AOL became popular offering dial-up connections.

DSL – Asymmetric Digital Subscribers Lines are offered by telephone companies. The telephone wire (twisted pair) is split into two channels – one for voice and the other for data. AT&T is offering DSL at speeds ranging from 384 Kb/sec to 6Mb/sec downstream and 128Kb/sec to 3Mb/sec upstream.

Cable – Cable TV companies offer Internet service over their coax cableusing Ethernet. Since you share this Ethernet with your neighbors, yourspeed can potentially slow down. Cable Internet speeds range up to 20Mb/sec.

WiFi – If you live near a Hotspot, you can connect wirelessly at 11-54 Mb/sec.

Fixed Wireless – Different companies may offer other types of wireless connections.

Mobile Wireless – Smart Phones may use 3G. Adapters are Laptops may use WiMax.

FiOS – Fiber Optic Service is being offered by companies like Verizon at 30Mb/sec.

Electricity – Electric companies can deliver Internet over your electric wires.

A blog—also called a Web log—is a Web page that contains short, frequently updated entries in chronological order, typically as a means of expression or communication.

Tweeting, or microblogging, is a free service that allows members to post short updates—called tweets—about what they are doing at any moment.

Instant messaging (IM) allows you to exchange real- time typed messages with people on your buddy list— a list of individuals such as family, friends, and business associates whom you specify.

Webinars (Web seminars) are similar to Web conferences, but typically have a designated presenter and an audience.

A social networking site can be loosely defined as any site that creates a community of individuals who can communicate with and/or share information with one another.

Wikis, named for the Hawaiian phrase wiki wiki meaning quick, are a way of creating and editing collaborative Web pages quickly and easily.