Network Topologies

• Server


  Is a powerful computer in a network that provides specific services to users
• What do servers do?

  They manage what user can and can't do
• Client


  Is the term used for a computer (workstation) used by a user to access a network
• What is a network topology?


  In general terms, any computer or device connected to a network is referred to as a node

  Network topology describes how different nodes on a different network connect together
• What does a bus topology consist of?

  A single backbone cable that all nodes connect to
• Bus Topology

  • Only one device can send a message at a time
  • At either end of the backbone, a terminator is used to prevent messages bouncing back up the cable if they haven't been delivered
  • Since only one node can send a message, the Bus topology requires a method to prevent collisions.
• Advantages of a Bus topology


  Relatively cheap to install

  One node fails, rest will continue to operate

  Easy to add extra nodes
• Disadvantages of Bus topologies


  If the backbone cable is cut or damaged then the whole network will fail.

  The more nodes that are added the greater the risk of collisions and the slower the network will run
• Which topologies is the most widely used?


  Star topology
• Star Topologies

  This is the most widely used topology for wired and wireless networks.

  Every node directly connects to a central node, which is a central hub or switch.

  The central node directs data to the revelant node.

  Very flexible topology - home networks can mix wired and wireless connections
• Adavantages of star topologies

  Since each node is separately connected to the central node, if one node fails, the rest of the network will continue to function

  If the network is wired, a damaged cable only affects one node

  It's easy to locate faults

  Nodes can be added or removed without having to take the network offline
• Disadvantages of star topologies


  Central node fails then rest of network will fail.

  Network performance is dependent on the capacity of the central node which also determines the number of nodes that can connect.

  A lot of cabling is required for a wired star network , making it difficult and expensive to set up.
• Mesh topologies

  Each node on a mesh network connects to multiple other nodes
• What is a Full Mesh network?


  A network where every node is connected to every other node is called a full mesh.
• Adavantages of a mesh topology


  High fault tolerance, especially full mesh networks. Data can be rerouted to avoid failed nodes

  Nodes can be added or removed without the need to take the network offline

  Very scalable

  High perfoirmance because each node is connected to multiple other nodes
• Disadvantages Mesh Topology


  A fully connected wired mesh network is difficult and expensive to install. Not an issue for wireless mesh networks

  Security issues due to the network being P2P
• What do mesh netowrks enable a large number of to be connected over long distances?

  Internet of Things (IoT)
• Mesh netorks and IoT

  Machinery in harsh or inaccessible locations can connect wirelessly to share diagnostic data.

  Increasing used for traffic management in smart cities.

  Traffic management centre connects to video cameras and traffic signals to monitor and control traffic flow in real time to prevent congestion and create safer roads conditions.
• What are mesh netorks ideally suited to?

  Home automation - smart lighting, temperature control, security, and home entertainment.
• What is a hybrid network?


  A network that combines elements of different topologies
• What is the ultimate hybrid network?


  The Internet is the ultimate hydbrid netwrok