Network Devices

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Network Devices
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Hub 1

• A device that allows hosts to be connected
  together at common point
• Network traffic is seen by all hosts
• Simple low cost component
• Network traffic normally observed via leds
• Simplifies fault finding

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Hub 2

• Common wiring point
• Star topology network
• Synonym for Concentrator
• Multiple ports
• Different segments
• Retiming signals
• Redistribute simultaneously
• Reroute signals

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Hub diagram
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Repeater 1

• A simple device that extends the range of the
  network
• Helps reduces the effect of cable capacitance
• Simple low cost device
• Can provide UTP and BNC connectors

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Repeater Diagram
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Bridge 1

• A bridge may be used to connect two different
  networks together
• Simple, low cost device
• Connects different segments
• Transmits traffic between them

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Bridge 2

• Connects
• Segment types eg.
• Usually - Ethernet to Ethernet
• Does not break max wire length
• Max number in network
• 4-7, 4 hop rule

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Bridge 3

• Learning bridge
• Learns addresses on which side
• Medium Access Control MAC
• MAC OSI layer 2
• No add loc - forward by default
• Remote Bridge
• Ethernet one side
• Serial on other
• Serial to telephone line

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Bridge diagram
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Switch

• A switch introduces very little delay
• Switches can operate in full duplex mode
• Switches are functionally similar to hubs
• Network traffic is not seen by all hosts.

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Router 1

• Router routes data traffic in a network
• Routers normally learn and maintain a table of
  addresses
• Low, medium and high cost devices depending upon
  functionality

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Router 2

• Monitors OSI layer 3
• Protocol Level address
• TCP/IP
• Transmission control protocol /internet protocol
• Transfer packets between media types
• eg. Leased line, Ethernet,
• Token ring, X25, frame relay,
• Fibre distributed data interface.
• FDDI 100Mbit/s LAN. etc.

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Router Diagram
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Router switch module RSM

• Combines advantages of router and switch
• Research the following device
• Cisco 6509 - 60K