Networks

Networks

1. Factors that affect a choice of Network

   • Cost of the Network
     • Initial Purchase of Equipment
   • Size of Organisation
     • Needs can range from a small LAN to a global WAN
   • How the system will be used
     • Will they need large data storage
   • Existing systems to integrate
     • Networks are often not developed from scratch so need to fit in with existing systems
   • Performance in terms of reliability and user friendiness
     • Different parts of the organisation will have different performance requirements

2. Topology

   • The layout of a network or the physical configuration, how they are connected together

3. Bus Network

   • All devices are connected to a single shared cable called a backbone. Data can travel both ways on the backbone
     • + Not affected by adding different nodes or periferals
     • + Not affected by heavy network traffic as only the machine with the "Token" can transmit data so there is no collisions
     • + Cheap to install of expand
     • - Only suitable for small networks, up to 12 computers
     • - A break in the backbone renders the network unusable

4. Peer to Peer vs Client Server

   • Cost
     • Peer to Peer
       • No server needed so all computers can be the same
     • Client Server
       • Servers are expensive the buy
   • Status
     • Peer to Peer
       • All machines have the same status
     • Client Server
       • One machine (the server) is more important than the rest
   • Knowledge
     • Peer to Peer
       • No network manager is needed, each user takes responsibility for the network
     • Client Server
       • Needs specialist knowledge and technical knowledge to manage the network
   • Set up
     • Peer to Peer
       • Easy to setup, can be done by anyone
     • Client Server
       • Network systems require technical knowledge to set up and maintain
   • Reliability
     • Peer to Peer
       • No reliance on server so no worry about breaking down
     • Client Server
       • Unusable if the server breaks
   • Responsibility
     • Peer to Peer
       • Users decide which resources are able to be used by others
     • Client Server
       • Admin is performed centrally
   • Backups
     • Peer to Peer
       • Backups cannot be performed centrally, each user is responsible for backing up their own data
     • Client Server
       • Central backups and installation
   • File Storage
     • Peer to Peer
       • Harder to find files not stored centrally
     • Client Server
       • Centrally stored files are easier to find
   • Network Size
     • Peer to Peer
       • Only suitable for small networks
     • Client Server
       • More efficient and load tolerant for large networks

5. Ring Networks vs Star Networks

   • LAN/WAN
     • Star
       • Can be LAN or WAN, linking networks via gateways
     • Ring
       • Is a LAN so can only be accessed from within the network
   • Shape and position of the file server
     • Ring
       • A Peer to Peer network
     • Star
       • A Client Server network
   • Reliability
     • Ring
       • Do not risk data collisions
     • Star
       • If a spoke goes down, the others can still function
   • Faults
     • Ring
       • Faults are harder to locate
     • Star
       • Fault tolerant as if one cable breaks, the others can still function
   • Transmission Speeds
     • Ring
       • Transmission in only one direction so rather fast
     • Star
       • Different spokes can have different speeds
   • Security
     • Ring
       • Every device has access to the token making it easy to hack
     • Star
       • Everything goes through the central file server which can have firewalls and proxy servers allowing central control of messages and therefore high security
   • Cabling Costs
     • Ring
       • Ethernet cables are sufficient for a LAN
     • Star
       • WANs may need expensive fibre optic cables or satalite links

6. WIFI

   • + Allows inexpensive LANs to be set up without cables
   • - Power consumption is high, meaning that laptop batteries get exhausted quickly
   • + Allows the freedom to work anywhere a signal can be received
   • + Global set of standards so you can use WIFI anywhere in the world
   • + Can use a variety of devices like phones and tablets
   • - May be health problems with WIFI
   • - Security problems even when encryption is used
   • - Transmission speeds are slower than cables
   • - Very limited range

7. Remote Management

   • Network managers can use remote management to see users on the network
     • Check outgoing emails
     • Check internet sites visited
     • Log off computers
     • Check to see components which are failing
     • Clear printer queues