Student Web Server - Chapter 12 Behind the Scenes: Networking …staff · 2010-03-23 · Servers...

1

Technology in Action

Chapter 12

Behind the Scenes:

Networking and Security

Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

2

Networking Advantages

• Networks

– Increase productivity

– Enable the sharing of hardware resources

– Facilitate knowledge sharing

– Enable the sharing of software

– Facilitate Internet connectivity

– Enable enhanced communication


3

Client/Server Networks

• Server-based network

– Clients and servers

• Data flows efficiently

• Servers respond to

requests from clients

• Servers perform

specific tasks

• Scalable

• Centralized


4

Classifications of

Client/Server Networks• LAN

– Local area

network

– Computers

linked over

a small

geographic

region


5

Classifications of

Client/Server Networks• WAN

– Wide area network

– Computers linked over large geographic locations

• MAN– Metropolitan

area network

– Computers linked within a city or county


6

Classifications of


• PAN

– Personal area network

– Wireless devices connected in close proximity

to each other

• Intranet

– Private corporate network

– Protected by a firewall


Classifications of


• Extranets

– Only certain corporations or individuals can

access

– Useful for enabling electronic data

interchange

– Use virtual private networks (VPN) for security

added security measures

7Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

8

Constructing

Client/Server Networks• Servers

• Network topologies

• Transmission media

• Network operating

system (NOS)

software

• Network adapters

• Network navigation

devices (routers)


9

Servers

• Number and types of servers depend on

network size and workload

• Dedicated servers: (described below)

– Perform one specific function

• Authentication servers

– Keep track of network logins and services

available

• File servers

– Store and manage files


10

Servers• Print servers

– Manage client-requested printing jobs

– Create print queue (prioritize print jobs)

• Application servers– Act as a storage area for application software

• Database servers– Provide clients with access to database

information

• E-mail servers– Process and deliver incoming and outgoing

e-mail (anti-virus, anti-spam, anti-spyware, firewall)


11

Servers

• Communications servers

– Handle communications between networks,

including the Internet (firewall, anti-hacking)

– Often the only device on the network directly

connected to the Internet

• Web servers

– Host a Web site available through the Internet

– Markup pages, interaction with user


12

Network Topologies

• The physical or logical layout of

computers, transmission media, and other

components

• Types of network topologies

– Bus topology

– Ring topology

– Star topology

– Hybrid topology


13

Bus Topology

• All nodes are connected in sequence on a single cable

• Used most often in peer-to-peer networks

• Networked computers communicate with each other

• One computer transmits data at a time– Access methods avoid data

collisions

– Data is transmitted in packets

– 512-1024 bytes


14

Ring Topology

• Nodes are laid out in a ring.

• A token (data packet) flows in one direction from device to device.

• Recent versions have data transfer rates of up to 100 Mbps.


15

Star Topology

• Nodes connect to a central

communications device

(switch or hub).

• A node sends a signal to

the switch, which

retransmits it to the

destination node only.

• Hub-sends to all nodes

• A node accepts only

signals addressed to it (?).Copyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

16

Avoiding Data Collisions

on an Ethernet Network


17

Transmission Media

• The routes data takes to flow between

devices on a network

• Wired

– Twisted pair

– Coaxial

– Fiber-optic

• Wireless

• -usually microwave, could be RF


18

Choosing a Cable

• Maximum run length

• Bandwidth

• Bend radius

• Cable cost

• Cable and installation costs

• Susceptibility to interference

• Signal transmission methods


19

Twisted Pair Cable

• Pairs of copper wire

twisted around each other

• Twists make the wires less

susceptible to interference

• Shielded twisted pair (STP)

– Layer of foil shielding

• Unshielded twisted pair

(UTP)

– Cat 5E: Bandwidth 200 Mbps

– Cat 6: Bandwidth 1 Gbps

– No foil layerCopyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

20

Coaxial Cable

• Four components

– Copper core

– Nonconductive insulating material

– Braided metal

– Plastic cover


21

Fiber-Optic Cable

• Components include

– Glass or plastic fibers

– Cladding

– Outer jacket

• Uses light impulses

to transmit data

• Immune to

interference


22

Wireless Media

802.11 Standard

• Wi-Fi (short for Wireless Fidelity)

– 802.11b

– 802.11a

– 802.11g

– Super G

– 802.11n


23

Network Operating

Systems (NOS)

• Provide the protocol that controls the

communication among devices on the

network

• Many modern OSs include NOS client

software

• Major network operating systems

– Windows Server 2008

– UNIX

– Novell Open Enterprise ServerCopyright © 2010 Pearson Education, Inc. Publishing as Prentice Hall

24

Network Adapters

• Devices that enable computers to communicate on a network

• Network interface cards (NICs)

• Three functions

– Generate network transmission signals

– Create data packets

– Act as information gatekeepers

• Ethernet compliant

• Wireless NICs


25

Network Navigation Devices

• Media Access Control (MAC) address– Six two-digit numbers (such as

01:40:87:44:79:A5)

– Physical address of network adapter

– Internal network identification


26


• Switches and bridges– Send data on a

specific route through the network

– Bridges send data between collision domains

• Routers– Send information

between two networks


27


• Repeaters– Amplify a signal and

retransmit it

– Extend cable runs

• Hubs– Transmit signals; have

multiple ports• Receive a signal from a

device

• Reconstruct the signal

• Transmit the signal to all ports on the hub (amplifies also)


28

Network Security Threats

• Human errors and mistakes

• Malicious human activity

– Current and former employees hacking or

planting viruses

• Natural events and disasters

– Hurricanes, floods, fire

– Disaster Recovery Plan


29

Network Security

• Firewalls

– Prevent access to the network by

unauthorized users

– Composed of software and/or hardware

– Screen and validate data packets

– Bastion host/proxy server


30

Network Firewall Layout


Student Web Server - Chapter 12 Behind the Scenes: Networking …staff · 2010-03-23 · Servers...

Documents

Transcript of Student Web Server - Chapter 12 Behind the Scenes: Networking …staff · 2010-03-23 · Servers...