CSCI 101 - Chapter 3
October 1, 2014
Chapter 3 - The Basics of Networking
1. Internet - what it is and how it works
2. IP Addresses and Domain Names
3. WAN vs LAN
4. World Wide Web
Chapter 3 - Communication Between Computers
Synchronous: both sender and receiver are active at the same
time
Asynchronous: sending and receiving happen at different times
Broadcast: one sender connects to many receivers
Multicast: one sender connects to a specific group of receivers
Point-To-Point: one sender connects to one receiver
The Internet supports asynchronous point-to-point communication.
Chapter 3 - Internet
The Internet is a universal communication medium where each
computer connected to the internet is connected to each other
computer on the internet.
If n computers are connected to the internet and one new computer
is added, then there are n new potential connections made.
Chapter 3 - Client/Server Structure
Most interactions on the internet follow a client/server interaction
protocol:
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client requests web page
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server sends information
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client processes information and displays web page
Web Server: computer designed to store and send web page
information
Chapter 3 - IP Addresses
Internet Protocol address: a series of 4 unique numbers used
to identify the location of a specific computer.
IP addresses aren’t very human-friendly, so most computers are
also given a symbolic name based on a domain hierarchy.
domain: a related group of networked computers
Chapter 3 - Domain Name
My work computer’s domain name is cf491-01.cs.wwu.edu
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cf491-01 is the computer name
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which belongs to the Computer Science domain (cs)
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which belongs to the Western Washington University domain
(wwu)
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which belongs to the educational domain (edu)
Chapter 3 - TCP/IP
Transmission Control Protocol/Internet Protocol: process
that sends information through the internet.
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Information is split into many different IP packets, each with
a unique sequence number
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IP Packets are sent along the internet using whichever route is
available
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Destination source collects and assembles the packets in the
correct order
IP packets: hold one unit of information, the destination IP
address, and their sequence number
Chapter 3 - WAN vs LAN
The internet is a collection of wide area networks (WAN) where
computers are geographically far from each other, so information
may be transmitted over several different point-to-point
connections.
A local area network (LAN) connects computers close by with a
related purpose, typically can be linked with a common wiring
system called an Ethernet.
Chapter 3 - WAN vs LAN
Both WAN and LAN systems connect to the Internet via a
gateway, but through different systems
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Internet Service Providers - connect individual computers to
an internet gateway through a modem
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Internet Server - connects LAN systems to the internet
gateway directly
Chapter 3 - World Wide Web
The World Wide Web is a collection of files and computers called
Web servers which send files to the browsers on computers
connected to the internet.
Files can be:
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Web pages
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images or animation included in a web page
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services that help media to run on the web page
Chapter 3 - World Wide Web
Universal Resource Locator (URL): is the location of a certain
web page and is used by a computer’s browser to request the web
page information to be sent.
https://cse.wwu.edu/computer-science/pottsc2
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Protocol: https:// stands for Hypertext Transfer Protocol
which tells the computer how to handle the file.
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Server’s Computer Name: cse.wwu.edu is the server’s
domain name.
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Page’s Pathname: /computer-science/pottsc2 tells the
computer which file is requested.