Handson Networking Fundamentals

1
Hands-on Networking Fundamentals

• CECS 410 Computers Networks
• Notes, Part 18
• Basic Network Design

2
Objectives

• Determine factors that affect network design
• Implement guidelines for installing cable
• Use structured wiring and networking in your
  network designs
• Design a network for a home
• Design a network for an office or organization

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Factors that Affect a Network Design

• Planning should precede equipment purchase
• Nine factors to consider
• Purpose of the network
• Anticipated network traffic
• Redundancy requirements
• User movement
• Future growth
• Security considerations
• WAN connectivity
• LAN and WAN costs
• Existing network topology and resources

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Purpose of the Network

• Number one task match network with user needs
• Scenario bandwidth demand varies with office
• Architects produce drawings saved to large files
• File transmission likely to require high
  bandwidth
• Copywriters generate files with high text content
• Likelihood that files are smaller than
  architects'
• Likelihood that bandwidth need is also less
• General considerations
• What type of information is to be shared?
• What software applications are used?
• What resources are required to run applications?

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Purpose of the Network (continued)

• General considerations (continued)
• What components are to be shared?
• Examples printers, CD arrays, storage, and
  others
• What are the organizational business patterns?
• How are patterns associated with network use?
• What role does the network play in the business?
• What roles does network play in operational
  strategy?
• What types of computers are to be connected?
• What is the function of the computers on the
  network?
• What kinds of LANs and WANs are to interconnect?

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Anticipated Network Traffic

• Two primary factors to consider for a new network
• Number of users
• Types of servers and hosts that will run on
  network
• Scenario 1 home network without a server
• Low network traffic largely consisting of file
  sharing
• Scenario 2 home network for entertainment
• Traffic heavier due to use of streaming video
• Scenario 3 office with one server
• Traffic heavier into and out of server
  (bottleneck)
• Scenario 4 office with multiple servers
• Traffic to any one server is light (if tasks
  distributed)

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Anticipated Network Traffic (continued)

• Actions to take when upgrading a network
• Obtain benchmarks of current network use
• Consider traffic from specific devices
• Benchmark performance assessment
• Some benchmarks that can be collected
• Slow, average, peak activity in relation to work
  patterns
• Slow, average, peak activity at different network
  points
• Typical network activity related to certain
  applications
• Example benchmark tracking database server
  activity
• Determines slow, average, peak access times

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Redundancy Requirements

• In relation to network paths
• Provide extra cable and equipment
• Enable system to tolerate failure of one or more
  devices
• Increase redundancy if continuous LAN use
  required
• Include enough network paths to hide malfunction
• User should not be aware of need to reroute
  traffic
• Three examples when down time harms organization
• Users in office cannot access financial programs
• Bank unable to process user and cash transactions
• E-business cannot perform transactions on Web
  server

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User Movement

• Network should adapt to users required to
  relocate
• Business events requiring network to adapt
• Reorganization to meet challenge of changing
  markets
• Restructuring due to merger and/or acquisition
  activity
• Networks should be responsive to physical
  movement
• User may need network access while moving around
• Example user in a hospital or warehouse with
  laptop

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Future Growth

• Successful networks have growth potential
• Scalable networks extend original investment
• Several ways to accommodate growth
• Select 100BaseTX network if goal is 1000BaseTX
• Converts to 1000BaseTX better than 16 Mbps token
  ring
• Design networks around modern routers and
  switches
• Avoid use of older devices, such as bridges and
  hubs
• Install cable of Category 5e or better in cable
  network
• Employ standardized technology in wireless
  networks
• Example use 802.11 devices without proprietary
  add-ons

12
Security Considerations

• Security vital in office and home networks
• Levels of protection vary with network
• Examples of security level need by company type
• High payroll-processing company
• Moderate provider of a public database of health
  statistics

13
WAN Connectivity

• Varies with design of LANs
• Consider how LAN and WAN will interoperate
• Basic WAN connectivity need
• LAN requires DSL or ISDN lines to connect to
  Internet
• Complex WAN connectivity based on various needs
• Satellite communications for overseas connections
• Frame relay to join LANs in neighboring states
• T-3 lines for universal access to a Web site used
  to market products

14
LAN and WAN Costs

• Important factors in any LAN or WAN project
• Are constrained by budget or specific allocation
• Are projected using itemized list
• Communications cable (for a cabled network)
• Network devices
• Additional computers and printers required for
  network
• Network management/analysis software and hardware
• Installation
• Training
• Vendor consulting
• WAN service or leasing fees

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Guidelines for Installing Cable

• Cable plant is foundation for cable-based
  networks
• General guidelines for the network designer
• Install the highest-quality cable possible
• Install extra cable to allow growth and user
  movement
• Audit existing cable runs as needed
• Develop upgrade plan to meet three needs
• Network expansion
• High-speed communications
• Flexible WAN connectivity
• Ensure cable compliant with current IEEE
  specifications and fire codes

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Strategies for Upgrading Cable

• Plan to replace all legacy cable
• Multimode fiber-optic cable replaces thicknet
  backbone
• Switches or routers replace repeaters
• Category 5e cable replaces thinnet or Category 3
  cable
• Upgrade thinnet NICs to newer NICs
• Managing cable and connector costs
• Compare cost of new cable to maintenance cost of
  old
• Factor in increased productivity
• Variables of installation costs
• Labor needed to remove old cable
• Removal or neutralization of hazardous materials

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Strategies for Upgrading Cable (continued)

• Considering environmental requirements
• Plenum areas and areas that have EMI/RFI
• Considering extra cable requirements
• Install 20 percent to 50 percent extra cable
• Simplifies process of connecting future
  workstations
• Builds redundant transmission paths
• Create or redesign wiring closet locations

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Strategies for Installing the Cable

• Use structured wiring and structured networking
  principles
• Install wiring to meet or exceed maximum
  bandwidth
• Install Category 5e or better UTP cable to
  desktop
• Install multimode fiber-optic cable between
  floors
• Match cable run distances to appropriate IEEE
  specifications

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Strategies for Installing the Cable (continued)

• Install single-mode fiber-optic cable for long
  runs
• Use wireless options as an alternative
• Install 802.11 wireless options when cable not
  viable
• Ensure available standards are followed
• Install star-based cable plants
• Install only high-quality cable
• Follow all building codes, such as for plenum
  cable

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Strategies for Installing the Cable (continued)

• Handle cable with care
• Do not pull twisted-pair cable with force over 25
  lbs
• Follow exactly the rules for the cable bend
  radius
• Leave plenty of extra cable at endpoints
• Ensure contractor (if used) is qualified and
  licensed
• Properly ground all cable plants (consult
  EIA/TIA-607)
• Ensure cable and installation certified
• Cable to meet EIA/TIA, IEEE, and UL standards
• Testing equipment to meet EIA/TIA and IEEE
  standards
• Label all cable following the EIA/TIA-606 standard

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Using Structured Wiring

• Cable fans out as horizontal star from central
  location
• Details of central location
• May be telecommunications room or wiring closet
• Contains one or more switches or routers
• Requirements of structured wiring
• Flexible cabling, such as twisted pair
• Wiring nodes into a physical star
• Adherence to standards for horizontal wiring
• Defined by EIA/TIA-568-A or EIA/TIA-568-B
• Centralizing the cable plant in switches or
  routers

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Using Structured Wiring (continued)

• Requirements of structured wiring (continued)
• Intelligence built into the switches and routers
• Used to detect problems at the nodes
• Ability to isolate hosts and servers on cable
  segment
• Ability to provide high-speed links
• Includes hosts and servers and other network
  devices
• Horizontal wiring
• Encompasses a single floor in a building
• Fans out to various rooms and office areas
• Divides cable plant into discrete units (modular
  design)

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Using Vertical Wiring and Structured Networking

• Vertical wiring (riser cable)
• Cabling and network equipment used between floors
• Ties horizontal cables on floors to form logical
  backbone
• Principles to follow
• Deploy an extended star topology between devices
• Daisy-chain wiring closets between floors
• Use with redundant backplanes and power supplies
• Use high-speed cable (multimode fiber-optic
  cable)
• Not susceptible to EMI and RFI
• Reduces congestion on backbone
• Adhere to standards for vertical or backbone
  cabling
• Follow EIA/TIA-568-A or EIA/TIA-568-B

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Using Vertical Wiring and Structured Networking
(continued)

• Principles to follow (continued)
• Use riser-rated cable for through cable ports or
  shafts
• Follow UL/NEC standards for fire and flame
  resistance
• Install fire-stop material on cable throughway
  openings
• Structured network combines horizontal and
  vertical wiring
• How to implement a structured network
• Centralize network at strategic points
• Example place switches in wiring closet
• Connect points via high-speed links into chassis
  switch
• Place main chassis switch in machine room

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Using Vertical Wiring and Structured Networking
(continued)

• Benefits of a structured network
• Centrally locates network devices
• Centralizes or distributes network management
• Monitor network from station using SNMP
• Use network agents on each floor to gather
  information
• Perform much of the network maintenance in one
  area
• Add redundancy without much difficulty
• Segment network according to workgroup patterns
• Servers/hosts share UPS and conditioned power
  source
• Conditioned power provides known range of power
• Scales well and is amenable to high-speed upgrades

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Integrating Wireless Communications

• In a small network (home or office)
• May work well with one wireless access point
• Access point wireless bridge, switch, or router
• In a larger network (large organization)
• Combine wireless networking into structured
  network
• Example 1 multiple access points on a single
  floor
• Connect access points via cable to router
• Use DSL or T3 line to link router for Internet
  access
• Example 2 multiple-floor network
• Vertical portion consists of switches joined by
  fiber links
• Switches join access points on floor
• Account for practical distance between devices

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Designing a Network for a Home

• Similar to designing for larger network in
  business
• Conducted on a smaller scale
• Advance planning helps ensure successful results
• Structure of discussion of home design
• Tips for locating computers
• Using cabled or wireless designs
• How to maintain a home network

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Locating Computers

• Common design combines desktops and laptops
• Place desktop out of harms way, such as home
  office
• Connecting desktop and peripherals to power
  source
• Plug devices into power strip with surge
  protector
• Connect power strip to reliable, grounded outlet
• A few pointers for laptops
• Keep them out of reach of food, drinks, and
  children
• Avoid putting heavy items onto device
• Place laptop in position that allows for
  ventilation
• Keep wireless units away from sources of
  interference

34
Walking Through a Cabled Design

• Structured wiring/networking principles valid in
  home
• Seven ideas for cabled home network design
• Locate central switch in a protected area
• Ensure computer reachable with cable less than 90
  m
• Setting up multi-story home with multiple
  switches
• Use 10/100/1000BaseTX switches
• Link with Cat 6 cable and 1000BaseTX connections
• Install Cat 5e cable for switch connections to
  computers
• Use plenum cable in attics and crawl spaces
• Run cables through walls (do not staple to
  exterior)
• Run cable away from sources of interference

35
Walking Through a Wireless Design

• Two reasons for choosing wireless in the home
• Low-cost multifunction access points, such as
  routers
• 802.11g communications
• Points to consider in a wireless design
• Using an access point and ESS topology
• Test reach of access point (if used)
• Locate access point in protected area with stable
  power
• Take extra security measures when near other
  users
• Configure an SSID and use WPA and 802.11i
• Consider purchasing access point with firewall
• Plan for reach of devices to be under 30 meters

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Maintenance and Support Issues

• Remodeling home may affect reception
• Wireless access point may have to be relocated
• Reset switch or router if link not functioning
  properly
• Periodically inspect cable, replace damaged parts
• Problems connecting or maintaining connection
• Check network connecting configuration on
  computer
• Check Web for NIC/WNIC driver updates
• Ensure same SSID and security configuration is
  used on all wireless devices

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Maintenance and Support Issues (continued)

• General tips for checking connection
  configuration
• Ensure TCP/IP is installed in the operating
  system
• Check the IP address and netmask configuration
• Ensure computers on network have same network ID
• Ensure computers in same workgroup or domain
• Applies to Windows-based networks
• Inspect NIC/WNIC for physical connection status
• LED blinks (or remains on) if connection is
  working
• If LED does not blink, two actions can be taken
• Check devices connecting to NIC/WNIC
• Replace NIC/WNIC

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Maintenance and Support Issues

• Inspect cables and identify sources of
  interference
• Make sure network equipment functions properly
• Periodically check for updates and replacements
• Vendor may cut off service after end-of-life
  (EOL) point
• New network equipment offers number of advantages
• Equipment at beginning of EOL cycle
• Devices can be sent back to manufacturer for
  repair
• Technical support available
• Web sites can be visited for support and
  downloads
• Training programs more likely to exist

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Designing a Network Summary Tips

• Determine need and create network diagram
• Plan for high throughput and redundancy
• Utilize modern devices, such as switch with ASIC
  chip
• Explore cable and wireless options
• Use certified cable in context of structured
  network
• Install strong security if wireless option
  selected
• Scenario network home in historic area of town
• Select wireless option to preserve historic
  character
• Utilize DSL Internet connection
• Implement wireless router, including tests
• Configure SSID, WPA, and 802.11i for wireless
  security

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Summary

• Network design begins with needs assessment
• Design points traffic, redundancy and security
  needs, user movement, growth, WAN connectivity,
  cost
• Cable plant choice critical to cabled
  infrastructure
• Set up horizontal cabling in structured wire
  format
• Vertical cables connect horizontal cabling on
  floors

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Summary (continued)

• Use cable certified to meet EIA/TIA, IEEE, UL
  standards
• Manage and grow structured network from key
  points
• Use full-duplex communications to avoid
  collisions
• Apply office network design to home (smaller
  scale)
• Use routers to segment networks, control traffic

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Summary (continued)

• Use switches to separate collision domains
• Isolate host/server traffic to simplify
  management and reduce costs
• Use trunking to improve bandwidth and redundancy
  
• Combine cable and wireless designs to meet needs
  for stability and mobility
• Aggressive maintenance plan averts obsolescence