31436 Systems Software

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31436 Systems Software NetworksAUTUMN 2002

• Chapter 3 Local Area Networks

UTS Faculty of IT is a Cisco Regional Networking
Academy
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Local Area Networks

• High speed networks
• Covers a small geographical area
• Several different types of devices can be
  connected.
• Servers
• Workstations
• Printers
• Mass storage devices
• Suffers few errors provided its wired
  correctly! How do we do it? What devices do we
  use?

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LAN Topologies

• A topology is the type of structure a network is
  formed in.
• Physical topology
• The actual layout of network media and
  peripherals.
• Logical topology
• The way hosts communicate across networks. Often
  defined in networking specifications, eg. IEEE
  802.2/3 (Ethernet), 802.5 (Token Ring).

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LAN Physical Topologies
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LAN Devices
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Repeaters / Hubs

• Amplifies stream of bits as they come in one
  port, and send the amplified signal out the other
  port.
• Hence, they extend network segments beyond the
  100m limitation imposed by CAT5 UTP cable.
• 5-4-3 Rule 5 segments, 4 repeaters, 3 segments
  with hosts.
• Repeaters have one port in, one port out.
• Hubs are multiport repeaters.
• Layer 1 devices.

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Bridges / Switches

• Connects separate LAN segments together.
• Filters traffic based on MAC addresses of hosts
  on segments connected to it.
• Bridges have one port in, one port out.
• Switches are multiport bridges.
• Switches maintain full-duplex bandwidth amongst
  all devices connected to it.
• Layer 2 devices.

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Routers

• Connects separate LAN networks together.
• Finds the best path for data based on IP
  addresses.
• Connects to different networking technologies,
  eg. Ports for Ethernet, Token Ring, FDDI
• Routers are Layer 3 devices.

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Data Flow

• Layer 1
• Bits flow through media, regenerated if
  necessary.
• Layer 2
• Frames switched using MAC address.
• If local, do not forward to adjacent network
  segment.
• If non-local, forward to adjacent network
  segment.
• Layer 3
• Packets routed using IP address.
• If local, do not forward to adjacent network.
• If non-local, forward to adjacent network.

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An example network topology
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Welcome to my world )

• Daniel COMARMOND
• E-Mail dacomarm_at_it.uts.edu.au
• ICQ 6606132
• Phone [phone]
• Website http//charlie.it.uts.edu.au/dacomarm
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• Take care, and SMILE!!! )