NETWORKING AND THE INTERNET

CS160

NETWORK CLASSIFICATIONS

Networking and the Internet

NETWORK CLASSIFICATIONS

Size

Local Area Network (LAN)

Metropolitan Area Network (MAN)

Wide Area Network (WAN)

Intellectual Property

Open

Closed

TOPOLOGIES

PROTOCOLS

Token Ring

Messages passed in one direction

Each message ends back at original sender

PROTOCOLS (CONTINUED)

Carrier Sense, Multiple Access with Collision Detection (CSMA/CD)

Message sent across common bus

Only intended recipient reads

On collision, each sender waits before re-sending

COMBINING NETWORKS

Repeater

Physically connects two networks

Passes all traffic

May amplify signals to compensate for increased length

Bridge

Passes only messages for machines on a given segment

COMBINING NETWORKS (CONTINUED)

Switch

Connects two or more segments

Routes messages only to segment where recipient is found

When using repeaters, bridges, or switches the result is one large, homo-geneous network

COMBINING NETWORKS (CONTINUED)

Router

Connects two or more networks with dissimilar topologies

Builds networks of networks called internets

INTERPROCESS COMMUNICATION

Client-server

One server, many clients

Server must execute continuously

Client initiates communication

INTERPROCESS COMMUNICATION (CONTINUED)

Peer-to-peer (P2P)

Two processes communicating as equals

Peer processes can be short-lived

THE INTERNET

Networking and the Internet

THE INTERNET

Proper noun

Originated in Defense Advanced Research Projects Agency (DARPA) in 1960’s

Shifted from government to academia to commercial

INTERNET ARCHITECTURE

Domain: portion of the Internet that network or internet controlled by a single authority

Connected to the rest of the Internet by a router called a gateway

Internet Corporation for Assigned Names & Numbers (ICANN): Oversees the registration of domains

STRATEGIES FOR CONNECTING TO THE

INTERNET

Internet Service Provider (ISP): Provides connectivity to the Internet

Popular means of connecting:

Traditional telephone (dial up connection)

Cable connections

DSL

Wireless

Satelite

INTERNET ADDRESSING: IP ADDRESSES

Every computer on the Internet is assigned an Internet Protocol (IP) Address

IPv4

32-bits (4 bytes)

232 = 4,294,967,296 unique addresses

“Dotted quads” xxx.xxx.xxx.xxx

INTERNET ADDRESSING : IP ADDRESSES

(CONTINUED)

IPv6

128-bits (7 bytes)

2128 = 3.4 × 1038

5 × 1028 addresses for each of the 6.5 billion people alive today

252 addresses for each star in the known universe

10 billion billion billion times as many addresses as IPv4

INTERNET ADDRESSING: HOST NAMES

Mnemonic address made up of two parts: Domain name

Assigned by a registrar Example: linnbenton.edu Top level domain: Classification of domain owner

By usage – Example: .edu= education By country – Example: .co.uk = England

Subdomains and individual host names Assigned by domain owner Example: ml.linnbenton.edu

Translation between mnemonic addresses and IP addresses handled by name servers

TRADITIONAL INTERNET APPLICATIONS

World Wide Web (WWW) Electronic mail

(E-mail) File transfer protocol

(FTP)

Instant messaging (IM) VOIP Internet relay chat (IRC) Telnet

Secure Shell (SSH) Newsgroups

Archie Early index of files

available on FTP sites

Gopher Hierarchical menu-

based system for document retrieval (WWW-like)

Jughead Search engine for

Gopher

Veronica Another search engine

for gopher

THE WORLD WIDE WEB

Networking and the Internet

THE WORLD WIDE WEB

Hypertext and HTTP

Hypertext markup language (HTML)

Hypertext transfer protocol (HTTP)

Browser gets documents from Web server

Web page

Documents identified by URLs

Uniform resource locator

World Wide Web Consortium (W3C)

Standards body

A TYPICAL URL

HTML

Set of tags used to identify elements of a web page

Designed to be very simple to learn and use

<p>…</p>

<h1>…</h1>

<img src=“foo.jpg />

<a href=“http://www.linnbenton.edu” />

SAMPLE WEB PAGE