Technology%20in%20Action

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Technology in Action
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Technology in Action

• Chapter 12
• Behind the Scenes Networking and Security

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Chapter Topics

• Advantages of business networks
• Client/server vs. peer-to-peer networks
• Classifications of client/server networks
• Client/server network components
• Types of servers
• Network topologies
• Types of transmission media
• Network software
• Network adapters
• Moving data in a client/server network
• Securing networks

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Networking Advantages

• Networks
• Increase productivity
• Enable the sharing of hardware resources
• Enable the sharing of software
• Facilitate Internet connectivity

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Client/Server Networks

• Server-based network
• Clients and servers
• Data flows efficiently
• Servers respond to requests from clients
• Servers perform specific tasks
• Scalable network
• Centralized

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Classifications of Client/Server Networks

• LAN
• Local area network
• Computers linked together over a small geographic
  region

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Classifications of Client/Server Networks

• WAN
• Wide area network
• Computers linked over large geographic locations
• MAN
• Metropolitan area network
• Computers linked together within a city or county

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Classifications of Client/Server Networks

• PAN
• Personal area network
• Wireless devices connected in close proximity to
  each other
• Intranet
• Private corporate network
• Protected by a firewall

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Constructing Client/Server Networks

• Servers
• Network topologies
• Transmission media
• Network operating system (NOS)
• Network adapters
• Network navigation devices

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Servers

• Number and type of servers depend on network size
  and workload
• Dedicated server
• Performs one specific function
• Authentication server
• Keeps track of network logins and services
  available
• File server
• Stores and manages files

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Dedicated Servers

• Print server
• Manages client-requested printing jobs
• Creates print queue (prioritizes print jobs)
• Applications server
• Acts as a storage area for application software
• Database server
• Provides clients with access to database
  information
• E-mail server
• Processes and delivers in-coming and outgoing
  e-mail

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Dedicated Servers

• Communications server
• Handles communications between networks including
  the Internet
• Often the only device on the network directly
  connected to the Internet
• Web server
• Hosts a Web site available through the Internet

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Network Topologies

• The physical layout of computers, transmission
  media, and other components
• Types of network topologies
• Bus topology
• Ring topology
• Star topology
• Hybrid topology

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Bus Topology

• All nodes are connected in sequence on a single
  cable
• Used most often on 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

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Ring Topology

• Nodes are laid out in a ring
• Token (data packet) flows in one direction from
  device to device

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Star Topology

• Nodes connect to a central communications device
  (switch)
• A node sends a signal to the switch, which
  retransmits it to the other nodes
• A node accepts only signal addressed to it

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Avoiding Data Collisions on an Ethernet Network
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Transmission Media

• The routes data takes to flow between devices on
  a network
• Wired
• Wireless
• Wireless Fidelity (Wi-Fi)
• Uses radio waves
• 802.11 standard

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Choosing a Cable

• Maximum run length
• Bandwidth
• Bend radius
• Cable cost

• Installation costs
• Susceptibility to interference
• Signal transmission methods

Comparison of Characteristics of Major Cable Types Comparison of Characteristics of Major Cable Types Comparison of Characteristics of Major Cable Types Comparison of Characteristics of Major Cable Types Comparison of Characteristics of Major Cable Types
Cable Characteristics Twisted Pair (Cat 6) Coaxial (ThinNet) Coaxial (ThickNet) Fiber Optic
Maximum Run Length 328 feet (100 m) 607 feet (185 m) 1,640 feet (500m) Up to 62 miles (100 km)
Bandwidth 1,000 Mbps 10 Mbps 10 Mbps 100 Mbps to 2 Gbps
Bend Radius (Flexibility) No limit 360 degrees/foot 30 degrees/foot 30 degrees/foot
Cable Cost Very low Low Moderate High
Installation Cost Very low Low Slightly higher than ThinNet Most expensive because of Installation training required
Susceptibility to Interference High Low Very low None (not susceptible to EMI and RFI)
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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 layer

UTP
STP
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Coaxial Cable

• Four components
• Copper core
• Nonconductive insulating material
• Braided metal
• Plastic cover

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Fiber-Optic Cable

• Components include
• Glass or plastic fibers
• Cladding
• Outer jacket
• Uses light impulses to transmit data
• Immune to interference

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Wireless Media802.11 Standard

• Wi-Fi, short for Wireless Fidelity
• 802.11b - first cost-effective wireless devices.
• 802.11a, 802.11g bandwidth increased to 54 Mbps
• Super G -bandwidth to 108 Mbps
• 802.11n - will support higher throughput and
  greatly increased range

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Network Operating Systems (NOS)

• Provide the protocol that controls the
  communication between devices on the network
• Major network operating systems
• Windows Server 2003
• UNIX
• Novell NetWare

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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

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Network Navigation Devices

• Media Access Control (MAC) address
• Six 2-digit numbers (0140874479A5)
• Physical address of network adapter
• Internal network identification
• Repeaters and Hubs
• Amplify signals and retransmit them

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Network Navigation Devices

• Switches and Bridges
• Send data on a specific route through the network
• Bridges send data between collision domains
• Routers
• Send information between two networks

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Network Security

• Authentication
• User ID and password used to access the network
• Access privileges
• Enable access to certain network systems
• Physical protection measures
• Restrict physical access to sensitive network
  equipment
• Magnetic card readers
• Biometric access devices

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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

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Network Firewall Layout
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Chapter 12 Summary Questions

• What are the advantages of a business network?

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Chapter 12 Summary Questions

• How does a client/server network differ from a
  peer-to-peer network?

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Chapter 12 Summary Questions

• What are the different classifications of
  client/server networks?

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Chapter 12 Summary Questions

• What components are needed to construct a
  client/server network?

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Chapter 12 Summary Questions

• What do the various types of servers do?

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Chapter 12 Summary Questions

• What are the various network topologies?

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Chapter 12 Summary Questions

• What types of transmission media are used in
  client/server networks?

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Chapter 12 Summary Questions

• What software needs to be running on computers
  attached to a client/server network?

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Chapter 12 Summary Questions

• How do network adapters enable computers to
  participate in a client/server network?

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Chapter 12 Summary Questions

• What devices assist in moving data around a
  client/server network?

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Chapter 12 Summary Questions

• What measures are employed to keep large networks
  secure?