Transcript Book cover slide

Section 9.1
• Explain the structure of the Internet
• Define the role of regional networks
• Explain what an ISP does
Section 9.2
• Explain the Domain Name System
• Demonstrate how the DNS database system functions
• Identify the role of ICANN
Section 9.3
• Explain how IP addressing is used
• Define the five classes of IP addresses
• Demonstrate how to use subnet masks
Section 9.4
• Explain the function of a Web browser
• Describe different ways of searching for information
• Identify several ways the Web is used as entertainment
pp.
9.1
252-254
Structure of the Internet
Guide to Reading
Main Ideas
Key Terms
The Internet is a collection
of smaller networks.
Regional networks are
connected by high-speed
communications lines
called the backbone.
Internet Service Providers
provide access to the
regional networks to home
and business users.
backbone
regional network
Network Access Point
(NAP)
Internet Service Provider
(ISP)
pp.
9.1
252-254
Structure of the Internet
The Backbone
The Internet is an
internetwork. The
foundation of the Internet
is a backbone of highspeed communications
lines that interconnect
many regional networks.
backbone A high speed
communications path that
interconnects many regional
networks. (p. 252)
pp.
9.1
Structure of the Internet
The Backbone
The Internet is the largest network of networks.
252-254
pp.
9.1
252-254
Structure of the Internet
Regional and Other Networks
Regional networks
connect to a national
backbone through one of
many major locations
known as Network
Access Points (NAPs).
Most NAPs are created
and maintained by major
telecommunications
companies, such as MCI
and AT&T.
regional network A
collection of small networks.
For example, there are
regional networks that serve
the Northeast, Midwest,
West, East, Southeast,
Northwest, and Central
California. (p. 253)
Network Access Point
(NAP) The major location at
which regional networks
connect to a national
backbone to join the larger
Internet. (p. 253)
pp.
9.1
252-254
Structure of the Internet
Internet Service Providers
To connect to the Internet,
an Internet Service
Provider (ISP) is needed.
An ISP is an agent that
provides a pipeline to the
Internet.
Internet Service
Provider (ISP) An online
service provider. (p. 253)
pp.
9.2
256-261
Internet and Web Communities
Guide to Reading
Main Ideas
Key Terms
Internet sites are
categorized into domains
according to organization
type or geographic
location. Domain names
are resolved to IP
addresses by DNS
servers. ICANN is the
organization responsible
for assigning IP
addresses.
DNS name server
root server
cache
Internet Corporation for
Assigned Names and
Numbers (ICANN)
pp.
9.2
256-261
Internet and Web Communities
Domains
In addition to its physical structure and organization, the Internet
is built upon the concept of domains.
The Internet classification is called the Domain Name System
(DNS). DNS is used to uniquely identify sites based on a treelike
hierarchy. This hierarchy includes a top-level domain, a secondlevel domain, and, often, one or more subdomains.
pp.
9.2
Internet and Web Communities
Domains
Top-level domains organize sites by geography or
organization type.
256-261
pp.
9.2
256-261
Internet and Web Communities
DNS Databases and IP Addresses
DNS also refers to
databases distributed among
a number of DNS name
servers.
In reality, apple.com is just
an easy name to remember.
On the Internet, sites are
identified by an Internet
Protocol (IP) address. An IP
address is a 32-bit number. It
is divided into four 8-bit
groups that look like the
following:
192.168.1.100
DNS name servers A server
that holds and looks through
its DNS database to match
domain names to IP
addresses, then resolves the
IP address. (p. 258)
pp.
9.2
256-261
Internet and Web Communities
DNS Databases and IP Addresses
The root servers (or
servers) responsible for
sites within the .com
domain contain the
information needed to
locate the server for
apple.com. That is all it
does. The root server
does not concern itself
with any lower levels—
subdomains—within
apple.com.
root server A DNS server
that is responsible for
tracking top-level domain
names (.com, .org, .net, and
so on). (p. 259)
pp.
9.2
Internet and Web Communities
DNS Databases and IP Addresses
Requests are passed up the chain of DNS servers until an
address is resolved or is not found.
256-261
pp.
9.2
256-261
Internet and Web Communities
ICANN
The responsibility for
registering domain names
is handled by a the
Internet Corporation for
Assigned Names and
Numbers (ICANN).
Internet Corporation for
Assigned Names and
Numbers (ICANN) A
nonprofit organization that
registers domain names,
preserves the operational
stability of the Internet, and
oversees the Internet’s root
server system. (p. 261)
pp.
9.2
Internet and Web Communities
You Try It
• Activity 9A – Finding Domain Registration Information
(p. 258)
• Activity 9B – Displaying the DNS Cache (p. 260)
256-261
pp.
9.3
262-267
Internet Connections & Addressing
Guide to Reading
Main Ideas
Key Terms
IP addresses are used to
uniquely identify computers
on the network. Subnet
masks are used in
conjunction with IP
addresses to identify the
network ID and the host ID.
Network functions aid in
working with IP addresses.
address space
loopback address
subnet mask
Internet Protocol version 6
(IPv6)
Address Resolution Protocol
(ARP)
Reverse Address Resolution
Protocol (RARP)
Dynamic Host Configuration
Protocol (DHCP)
Windows Internet Naming
Service (WINS)
pp.
9.3
262-267
Internet Connections & Addressing
IP Addressing
When a domain is registered, an IP address, or block of IP
addresses, is assigned to that domain.
This address identifies two things:
• the network
• a host (computer) on that network
A system of IP address classes is used to keep one
network separate from other networks.
pp.
9.3
262-267
Internet Connections & Addressing
IP Addressing
A range of assignable IP
addresses is called the
address space. However,
not all these addresses
are available for
assignment, as some are
reserved for special use.
The address 127.0.0.1 is
a special reserved
address, called a
loopback address.
address space A range of
assignable IP addresses
technically runs from 0.0.0.0
to 255.255.255.255. (p. 263)
loopback address A special
reserved IP address used to
test whether a computer’s
network capabilities are
functioning. (p. 263)
pp.
9.3
262-267
Internet Connections & Addressing
IP Addressing
The assignable address space is divided into five classes
and is identified by the binary form of the IP address.
pp.
9.3
262-267
Internet Connections & Addressing
IP Addressing
For an IP address to be
valid, it must use a
combination of an IP
address, along with a subnet
mask.
You can use an easy formula
to calculate the number of
subnets a given number of
subnet bits will create.
2n = number of subnetworks
The n represents the number
of bits used as the subnet ID.
subnet mask A mask used
in conjunction with IP
addresses to determine the
portion of the IP address that
identifies the network and the
portion that identifies the
host. Identifies the first 24
bits as the network address,
with the remaining 8 bits
identifying the host. (p. 263)
pp.
9.3
262-267
Internet Connections & Addressing
IP Addressing
Internet Protocol
version 6 (IPv6) is the
latest generation of the IP
protocol.
IPv6 uses 128-bit
addresses, which works
out to 4 billion times 4
billion times 4 billion times
the current number (4
billion) of IP addresses.
Internet Protocol version 6
(IPv6) The latest generation
of the IP protocol; also called
Next Generation IP, or Ipng.
(p. 265)
pp.
9.3
262-267
Internet Connections & Addressing
Working With TCP/IP Addresses
Many important services
are involved for IP
packets to get transmitted
between Internetnetworked computers.
• Address Resolution
Protocol (ARP)
• Reverse Address
Resolution Protocol
(RARP)
Address Resolution
Protocol (ARP) A protocol
used to determine the
hardware address (MAC
address) that corresponds to
an IP address. (p. 265)
Reverse Address
Resolution Protocol
(RARP) A protocol used to
look up the IP address when
the hardware, or MAC
address, is known. (p. 265)
pp.
9.3
262-267
Internet Connections & Addressing
Working With TCP/IP Addresses
• Dynamic Host
Configuration Protocol
(DHCP)
• Windows Internet Naming
Service (WINS)
• Gateways
Dynamic Host
Configuration Protocol
(DHCP) A protocol used to
automatically assign IP
addresses within a network.
(p. 266)
Windows Internet Naming
Service (WINS) A service
used to match computer
names to IP addresses in a
Windows network. (p. 266)
pp.
9.3
Internet Connections & Addressing
You Try It
• Activity 9C – Configuring DHCP, WINS, and Gateway
(pg. 266)
262-267
pp.
9.4
269-274
Internet and Web Services
Guide to Reading
Main Ideas
Key Terms
Web browsers display pages
written in HTML format.
Search engines index and
categorize sites on the Web
to make information easy to
find. Services like FTP,
NNTP, and Telnet add
capabilities such as file
transfer and remote control
of computers. The Web
provides a variety of
entertainment options.
Hypertext Markup Language
(HTML)
search engine
Network News Transfer
Protocol (NNTP)
newsgroups
Usenet
Telnet
online gaming
multiuser dungeon (MUD)
instant messaging (IM)
pp.
9.4
269-274
Internet and Web Services
Web Browser
A Web browser is a
software application that
is used to view Internet
documents written in
Hypertext Markup
Language (HTML).
Popular browser software
includes Microsoft Internet
Explorer and Apple’s
Safari. Other popular
browsers can be
downloaded for free,
including Netscape
Navigator, Opera, and
Mozilla.
Hypertext Markup
Language (HTML) The
language used to define the
structure and layout of a
Web page. HTML acts as a
set of instructions that tells
browser’s software how and
where to place the page’s
content. (p. 269)
pp.
9.4
269-274
Internet and Web Services
Search Engines and Services
A search engine uses a
spider, or robot, to “crawl”
the Web on a regular
basis. As it does this, it
creates an index of every
page it can find. Based on
a complex set of criteria,
pages can be ranked.
search engine A sight that
uses automated software to
index the Web. (p. 271)
pp.
9.4
269-274
Internet and Web Services
FTP
Although search engines and the Web make finding
information a snap, there are also other ways to find and
retrieve information. One of the most widely used is the
File Transfer Protocol (FTP).
FTP functionality is built into today’s Web browsers,
making other software largely unnecessary. All you have to
do is point your browser to an FTP site, log on, and start
copying files.
pp.
9.4
269-274
Internet and Web Services
E-mail
One of the most popular uses of the Internet is e-mail. This
global message service enables families, friends, business
associates, and even complete strangers to communicate
with one another. E-mail addresses are used to identify
the “mailbox” of the person.
pp.
9.4
269-274
Internet and Web Services
News
News on the Internet has two
different meanings.
1. News broadcasts
2. News is handled on the
Internet by services based on
the Network News Transfer
Protocol (NNTP).
NNTP is a protocol that is
used to distribute collections
of articles called newsfeeds
to a bewildering array of
Interest-based newsgroups.
Network News Transfer
Protocol (NNTP) A standard
that is used to distribute
collections of articles called
newsfeeds. (p. 273)
newsgroup A group of
individuals on the Internet
with a common interest in a
particular subject or set of
related subjects.
Newsgroups receive and
post articles and discussions.
(p. 273)
pp.
9.4
269-274
Internet and Web Services
News
Usenet is one of the most
well-known news services
that implements NNTP.
When more than one user
responds to a message,
the original topic is called
a thread.
Usenet An electronic
bulletin board where users
can post messages 24 hours
a day, 365 days a year.
(p. 273)
pp.
9.4
269-274
Internet and Web Services
Telnet
Telnet is like remote
control for computers. As
long as the connecting
computer has terminal
emulation capabilities, it
can use the resources
and programs installed on
the remote machine.
Telnet A TCP/IP protocol
that runs on the Application
Layer and allows a computer
to log on to a remote
computer and pretend it is
attached directly to the host.
(p. 273)
pp.
9.4
269-274
Internet and Web Services
Online Gaming, MUDs, Chats, and
Instant Messaging
And, finally, what about
some of the really fun
things people get involved
in on the Internet?
• Online gaming
• Multiuser dungeons
(MUDs)
• Chats
• Instant messaging
online gaming Games available on
the Internet that pit players from
around the world against one another
in real-time. (p. 274)
multiuser dungeon (MUD) A type of
game available on the Internet that is
an outgrowth of the popular
dungeons and dragons type of
interactive, multiplayer role playing
games (RPGs). (p. 274)
instant messaging (IM) A type of
e-mail process service that enables
two (or more) people to establish a
private communications channel,
similar to calling someone on the
phone. (p. 274)
pp.
9.4
Internet and Web Services
You Try It
• Activity 9D – Searching By Category (p. 270)
• Activity 9E – Narrowing a Web Search (p. 271)
269-274
Chapter 9
Resources
For more resources on this chapter, go to the Introduction
to Networks and Networking Web site at
http://networking.glencoe.com.