Connecting computers

1
Connecting computers

• Unit objectives
• Identify the components of a network
• Describe wired network connections
• Compare wireless networking standards
• Describe the different network architectures

2
Topic A

• Topic A Networking concepts
• Topic B Wired network connections
• Topic C Wireless network connections
• Topic D Network architectures

3
Local area network

• Located within a confined area
• Connected by wires or radio waves
• Devices communicate and share data and services
• Each device is called a node
• Computer
• Router
• Printer
• Sensing device
• Video camera
• Controller

continued
4
Local area network, continued

• Host is always a computer
• Can be connected to the Internet
• Direct cable connection
• Telephone link via modem

5
Example of a LAN
6
Basic types of networks

• Peer-to-peer network
• Client/server network

7
Peer-to-peer model

• Each computer has same authority
• User decides to share resources
• User responsible for many administrative tasks
• Windows XP and Windows 2000 Professional support
  peer-to-peer
• Connect to form small LAN
• Wired
• Wireless

8
A peer-to-peer network
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Peer-to-peer authentication

• Each user enter valid user ID and password
• Authentication
• Validation
• Logging on
• Authenticated by the client operating system
• Local user account
• Exists only on a single computer

10
Local user account

• Collection of user information
• Includes
• User ID
• Password
• Permissions

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Using a shared resource

1. Click Start and choose My Computer
2. Click My Network Places
3. Click View workgroup computers
4. Double-click the icon for the computer where the
   shared resource exists

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Client/server model

• Network operating system manages network
  resources on LAN
• User accounts
• Printers
• File sharing
• Single network user ID and password
• Authenticate against the NOS
• Domain model
• Administrator assigns permissions
• Server stores info in database

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A client/server network
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Network client

• Client OS sends user ID and password to NOS on
  server
• Server verifies against database
• Uses network client software on client computer
• Network client communicates with NOS on server

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The logon process

1. The network client on the client computer
   displays a logon screen to the user
2. The user enters his user ID and password at the
   logon screen and clicks OK
3. The network client then sends this information to
   the NOS for authentication
4. After the user ID and password have been
   authenticated, the user can gain access to the
   computer and to the network resources

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Connections

• Established with a network adapter
• Type of connector varies with the type of network
  media
• NICs send and receive data
• Half-duplex
• Full-duplex

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Network protocols

• Languages used for network communication
• Send data in packets
• Common protocols
• TCP/IP
• IPX/SPX
• AppleTalk
• NetBEUI

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Activity A-1
Describing networking models and protocols
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Activity A-2
Identifying the components of a network
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Topic B

• Topic A Networking concepts
• Topic B Wired network connections
• Topic C Wireless network connections
• Topic D Network architectures

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UTP and STP

• Ethernet network
• Unsheilded twisted pair (UTP)
• Shielded twisted pair (STP)
• UTP
• Cat3 - 10 Mbps
• Cat5 - 100 Mbps
• Cat5e - 1 Gbps
• Cat6 up to 2.5 Gbps

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Cat5 installation

• Avoid
• Pulling to hard
• Bending it too sharply (kinking)
• Forcing it through too tight an opening
• Each network node needs its own cable from the
  patch panel
• Cant splice
• Cant run too close to AC wires at least a foot
  apart
• Install highest quality and capacity cable
• Can run parallel coaxial or fiber

23
Composite cable

• Combines Cat5 and other transmission cables in a
  single PVC jacket
• Makes multiple-wire installation easier
• Saves cost of future wiring
• May contain
• Two Cat5 wires for network
• Two shielded RG-6 coaxial cables
• Fiber optic line

24
Plenum wiring

• An enclose in a building that moves air for
• Heating
• Cooling
• Humidity control
• Created by
• A false ceiling
• A false ceiling
• Metal duct work
• Contains high- or low-voltage wiring

continued
25
Plenum wiring, continued

• Cables must meet fire protection and
  environmental requirements
• To protect
• Enclose cables in a conduit
• Use cables with jackets
• Use cables made with fire resistant materials
• Use cables that are non-toxic at extreme
  temperatures
• Plenum cabling often coated with Teflon
• TP and coax both come in plenum cable types

26
Coaxial networks

• Supports older networks
• Contains a layer of braided wire or foil between
  the core and outside insulating layer
• Shielding protects from EMI
• Layer of plastic separates core from insulating
  layer to prevent data signal damage or loss
• Ethernet uses RG-58
• Thinnet cable

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Thinnet cable
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Thicknet cables

• RG-8 or RG-11 cables
• Dual shielding
• Dont bend easily
• Carry signals up to 500 meters
• Used for backbone, not node drops
• RG-59 (for cable TV) and RG-6 (for surveillance
  cameras) not suitable for networks
• RG-62 used for old ARCnet networks
• Check type carefully

29
A thicknet cable
30
Coax connectors

• Thinnet cables connect using a BNC barrel
  connector
• Segments use T-connectors
• Line end uses terminator
• Terminator prevents signal reflection

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Coax cable connectors
32
NIC with coax connector
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Thicknet connectors

• Vampire tap
• Tap contains metal spikes
• Spikes penetrate cable to make connection
• Transceiver connects to cable via AUI port or DIX
  connector

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Thicknet vampire tap
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Activity B-1
Examining coaxial cable and connectors
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Cat5 TP cable connectors

• RJ-45
• Eight wires
• RJ means Registered Jack
• is the wiring pattern
• EIA/TIA-568-A defines two wiring patterns
• T568A
• T568B
• Pins are numbered left to right, 1 8
• Pins connect to colored wires

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RJ-45 and RJ-11 connectors
RJ-45
RJ-11
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RJ-45 wiring
Pin T568A standard T568B standard
1 Green/white Orange/white
2 Green Orange
3 Orange/white Green/white
4 Blue Blue
5 Blue/white Blue/white
6 Orange Green
7 Brown/white Brown/white
8 Brown Brown
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EIA/TIA-568-A standards

• T568A preferred for residential
• T568B preferred for commercial
• Both electrically identical
• Pin 1 always to pin 1, pin 2 always to pin 2,
  etc
• Pick one standard and use it for all wiring

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Terminating cable to an RJ-45 plug
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Terminating CatX to RJ-45 jacks

• Use an RJ-45 punchdown tool
• Expensive versions use a compression spring
  hammering action
• Produces uniform connections
• Use type 110 IDC terminals
• Remove 1 ½ of jacket from cable
• Untwist full length of exposed wire pairs
• Place cable end onto jack
• Arrange wires into IDC slots
• Use punchdown tool
• Snap on protective cover

42
TIA 570 specifications

• Specifies residential telecommunications wiring
• Specifications include
• Topology
• Distribution devices
• Layouts for single and multiple family homes
• Performance criteria and field tests
• Auxiliary disconnect outlets
• Two grades 1 and 2

43
Activity B-2
Examining twisted pair cables and connectors
44
Fiber optic cables

• Carry light-based data through strands of glass
• Fastest and most expensive transmission media
• Used as backbone
• Used for long-distance lines
• Composed of
• Glass or plastic strand (core)
• Core clad in glass tube
• Outer, insulating, rubberized jacket

continued
45
Fiber optic cables, continued

• Single-mode or multi-mode
• Issues
• Most expensive to install and manufacture
• Data cant transmit through broken glass
• Benefits
• Not subject to EMI or wiretapping
• Very high transmission speed
• Little or no attenuation
• Length up to 10 miles
• Speeds 100 Mbps to 1 Gbps

46
Fiber optic cable connectors
47
Activity B-3
Discussing fiber optic cables and connectors
48
Linking computers

• RS-232
• IEEE 1394/Firewire
• USB 2.0

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RS-232

• EIA232
• Interface standard for data communications
  equipment
• Specifies
• Signal voltages
• Signal timing
• Signal function
• Protocol
• Mechanical connectors
• Employed in null-modem cables
• RS-232D uses RJ-45 connectors
• Max length is 50 feet 500 feet for asynchronous
  data

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IEEE 1394/Firewire

• Create a peer-to-peer network between two Windows
  XP computers
• Max. cable length is 15 feet
• Communication speeds of 100, 200, and 400 Mbps
• Windows 2000 needs third-party product for
  Firewire networking
• Multiple Firewire ports can daisy chain for
  more than two computers
• Place repeaters every 15 feet for max of 237 feet.

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Windows XP IEEE 1394/Firewire
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1394 Connection Properties
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USB 2.0

• No designed to establish a LAN
• Use a USB bridge device between two computers
• Use a USB hug for more than two computers
• Cant direct connect two computers USB port to
  USB port with a USB cable
• USB 2.0 has data transfer rate of 480 Mbps

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Activity B-4
Examining the IEEE 1394/FireWire connection
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Network Interface Card

• Adapter card
• Plugs into expansion slot
• Connects externally through USB port
• NIC ports connect to network using cable
• Supports only one of the three
• Ethernet
• Token Ring
• FDDI
• Multiple type of ports for different cable types

continued
56
Network interface card, continued

• Function is to send and receive data
• Converts data into appropriate network signal
• Transceiver makes the conversion
• May have more than one type of transceiver

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An Ethernet combo NIC
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Examples of NIC cards
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NICs

• Have MAC addresses
• Must match network architecture
• Most all are PCI cards
• Older cards
• Set IRQ, DMA, and I/O addresses

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Activity B-5
Installing a NIC
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Topic C

• Topic A Networking concepts
• Topic B Wired network connections
• Topic C Wireless network connections
• Topic D Network architectures

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Wireless LAN

• Uses radio waves or infrared light
• Uses wireless NIC
• Wireless NIC uses antenna to send and receive
  signals
• Popular
• Where cable is difficult to install
• Where there are mobile users
• Communicate directly or through a WAP

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Wired network with wireless segments
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Wireless network benefits

• Inventory is more convenient when employees can
  freely walk around the warehouse or organization
• Devices like personal digital assistants (PDAs)
  and Tablet PCs can be used in hospital wards to
  track patients, and doctor visits
• Mobile workers moving between offices, and
  telecommuters coming into the office, can more
  easily connect to the LAN from almost anywhere
• Online information is always available for
  research or information retrieval

continued
65
Wireless network benefits, continued

• Production on manufacturing shop floors can be
  readily evaluated
• Wireless network infrastructure can be moved to a
  new building more easily
• The cost of providing network access to buildings
  is substantially lowered

66
WAN issues

• Slower than wired networks
• Security

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Wireless protocols

• Wi-Fi (Wireless Fidelity)
• Bluetooth
• 802.11a
• WiMax
• IEEE1394
• IEEE 802.11g
• USB

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Activity C-1
Comparing wireless networking standards
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Topic D

• Topic A Networking concepts
• Topic B Wired network connections
• Topic C Wireless network connections
• Topic D Network architectures

70
Ethernet

• Most popular LAN
• Good balance between
• Ease of setup
• Use
• Speed
• Cost
• Three types
• 10-Mbps Ethernet
• 100-Mbps Ethernet
• 1000-Mbps Ethernet (Gigabit Ethernet)

continued
71
Ethernet, continued

• Most use STP, UTP or fiber-optic cable
• Older installations use thin Ethernet or thick
  Ethernet

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Ethernet topologies

• Bus topology
• Star topology

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Bus and star Ethernet designs
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Comparing star and bus designs

• Star may be slower than bus, especially with many
  nodes
• Star may have more data collisions

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Combined bus and star designs
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Token Ring

• Operates at slower speeds than Ethernet
• Physically arranged in a star
• Protocol for data control uses a token
• All data travels in a circle (ring) on the
  network
• Each node is connected to a MAU by two wires
• Token travels up and down wires and between MAUs

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A Token Ring network
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Wireless networks

• Communicate with an access point or wireless hug
• NIC includes transceiver and antenna
• Communicates over short distances using radio
  waves

79
A wireless network design
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Fiber optic cable networks

• FDDI
• Large, fast networks
• Almost exclusively use fiber optic cables
• Communication speeds of 100 Mbps
• Used in large commercial buildings and backbones
  to join LANs

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Activity D-1
Identifying the characteristics of the various
physical architectures
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WAN bandwidth technologies

• T lines and E lines
• X.25 and frame relay
• ATM
• Mesh topology

83
Activity D-2
Discussing WAN bandwidth technologies
84
Unit summary

• Identified the components of a network
• Described wired network connections
• Compared wireless networking standards
• Described the different network architectures