Category Archives: Computing Higher

1. Computer Systems, Computing Higher

Star Network

Advantages

  • Easy to extend the network.
  • A failure of one node will only affect that node (unless central node)
  • A channel failure will only affect the outer node on that channel.

Disadvantages

  • The whole network depends on the proper functioning of the central node.
  • Cabling cost is high because each node has its own channel
1. Computer Systems, Computing Higher

Mesh Network

Advantage

  • Data can be redirected when some channels are busy or failed.
  • Very robust network.
  • The failure of one node will only affect that node
  • Channel failure will have no effect as alternative channels are available

Disadvantage

  • Extra cabling makes this an expensive
  • Complex cabling leads to higher maintenance of the network.
1. Computer Systems, Computing Higher

Ring Network

Advantage

  • High data transfer (bandwidth)
  • Mechanism to bypass a failed node so a failure of one node will only affect that node

Disadvantage

  • Difficult to designing and extending (complexity of the electronics)
  • A channel failure will disable the entire network
  • Can be expensive because of the complexity.
1. Computer Systems, Computing Higher

Client Server Vs Peer to Peer

Client – Server

  • All resources (printer, files and Internet) on the network are controlled by the server.
  • Centralised storage of data
  • Centralised storage of data means regular back-ups can be made from the server.
  • Security is set of easily using a server and client network.  Usernames and password are easily given along with access levels for users.
  • Used in businesses (banks) and organisations (schools, colleges, universities.)

Peer to Peer

  • No centralised storage.  Each workstation stores its data independently.
  • No centralised storage means no back up system.
  • Security is difficult because there is no mechanism for central access.
  • Best suited with a trusting environment.  Family home or small office.
1. Computer Systems, Computing Higher

Hub / Switch Comparison

Hub

  • A hub contains multiple ports. When a packet arrives at one port, it is copied to the other ports so that all segments of the LAN can see all packets.
  • Cheap to purchase and install
  • Problem – All devices on the network share the same bandwidth

Switch

  • Will look at traffic it receives and based on the destination address it will direct the traffic to the port.
  • Devices don’t share the same bandwidth. The network will not be slowed down.
  • Packet is delivered to address port. Problem – Require additional set-up and expensive to purchase.