Network Devices

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 Introduction to Network Devices

Repeater:

  • Operates at the physical layer.
  • Its job is to regenerate signal over the same network before the signal becomes too weak or corrupted.

Hub:
  • It is a multiport repeater.
  • It connects multiple wires coming from different branches.
  • Cannot filter data.
  • They do not have the intelligence to find out the best path for data packets which leads to inefficiencies and wastage.

Types of Hubs:

1.Active Hub:

  • Hubs that have their own power supply and can clean, boost, and relay the signal along with the network.
  • Serves both as a repeater as well as a wiring center.
  • Used to extend the maximum distance between nodes.
2. Passive Hub:
  • Hubs that collect wiring from nodes and power supply from the active hub.
  • Relay signals onto the network without cleaning and boosting them.
  • Can't use to be extend the distance between nodes.
3. Intelligent Hub:
  • Works like active hubs and includes remote management capabilities.
  • Provide flexible data rates to the network devices.
  • Enables an administrator to monitor the traffic passing through the hub to configure each port in the hub.
Switches:
  • It is a multiport bridge with a buffer and a design that can boost its efficiency and performance.
  • Can perform error checking before forwarding data, which makes it very efficient.


Routers:
  • Routes data packets based on their IP addresses.
  • Connects LANs and WANs together and have updating routing table based on which they make decisions on the routing data packets.


Hubs and network bandwidth
  • Amount of data that can be transferred in an interval is network bandwidth.
Bandwidth sharing: When all computers connected to the hub must share the amount of bandwidth the hub provides.

Difference between Hub and Switch

Network Switches:
  • It reads data in the message.
  • Determines which port the destination device is connected to.
  • Forwards the message to only that port.

Steps of switch operation:
  • Switch receives a frame.
  • Switch reads the source and destination MAC addresses.
  • The switch looks up the destination MAC address in its switching table.
  • The switch forwards the frame to the port where the computer owning the  MAC address is found.
  • The switching table is updated.
Difference between Switches and Routers



 Routers work with IP addresses and routing tables.
  • Default route: where to send a packet when the router doesn't have an entry in its routing table.
  • Network unreachable: Message sent when the network can't be found and no default route.
  • Default gateway: In a computer's IP address configuration - the IP address of the computer's router.

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