Networks

Networks

1. Dialup : Broadband

   • Dialup is very slow and limits it's use - a download on dialup can take a matter of minutes compared to broadband
   • Dialup can be used anywhere there is a phone line
   • If only a light user then dialup might be cheaper as you only pay for what you use
   • Broadband means you can stream and watch or listen to films and music
   • It does not tie up your phone line
   • Broadband can make cheap phone calls via the internet
   • Broadband Makes vide conferencing possible
   • Dialup
     • Using a dialup modem to connect to the internet is very slow and this limits its use. If you have used broadband then use a dialup connection, you will notice it is frustratingly slow.
     • Dialup uses a modem which converts the digital signals into a series of sounds which are then passed along the telephone line. The sound signal is then converted back to a digital signal which the computer is able to understand at the end of the wire
   • Broadband
     • Broadband gives you much faster access and transfer speeds to the internet and allows you to watch online videos, download files quickly, listen to online radio, watch tv programme that you have missed and so on. None of these would be possible without a fast broadband connection

2. Peer to Peer : Client Server

   • Peer to Peer - All machines have the same status - ~client server - One machine more important than the rest
   • Peer to Peer - Cost saving as no server is needed so all computers can be the same - Client server - More expensive as servers are expensive to buy
   • Peer to Peer - Only suitable for very small networks 15 or less - Client server - more efficient for larger networks
   • Peer to peer - harder to find files which aren't stored centrally - Client server - centrally stored files are easier to find
   • Peer to peer - No reliance on server so no worry about server breaking down - client server - If server breaks down network is unsuable
   • Peer to peer - Users need more It Knowledge - Client server - Network manager allocates access to resources on network

3. Network Choice

   • How the system will be used - what types of applications do the users require
   • Existing systems to integrate - can the current stock of pc's be used on the new network
   • Performance in terms of reliability - different parts of the organisation have different performance requirements
   • Size of the organisation - Needs can range from a small LAN to a global WAN
   • Cost - Initial purchasing of equipment

4. Ring : Star : Bus

   • Advantages of Ring - No collisions - Higher Transmission Speeds
   • Advantages of Star - Different speeds possible on different spokes - Easy to add extra computers without disturbing the network
   • Disadvantages of Ring - Faults are difficult to locate - Break in the cable and the network won't work
   • Disadvantages of star - Higher costs due to large amounts of cabling needed making it more expensive - Dependance on central server
   • Bus - All devices are connected to a single shared cable called the backbone. Signals are passed in either direction along the backbone
   • Ring - Ring network is a peer to peer network because there is no server
   • Star - Central connection which connects all devices on the network together. Central connection can be a hub, switch or router
   • Advantages of bus - Cost effective becuase of the small amount of cable needed - Simple cable runs make it easier to install - Easy to add extra devices to the network
   • Disadvantages of bus - If more than 12 devices are connected to the network, performance of network is degraded - If break in backbone, network can't be used

5. User Accounts

   • Auditing keeps a record of who logged on like the user names, what details of files they accessed and when the times they logged off and on.
   • Auditing keeps a record of who has done what on a network

6. Wireless : Cabled

   • Wireless - Many computers are now able to connect to the internet or communicate with the other computers wirelessly. They communicate via radio waves which transmits through the air
   • Wireless what is needed - A broadband connection to the internet - A router - Wifi enable computers or you can buy a wireless adapter for older computers
   • How wireless works - Router is connected to the internet by a high speed broadband connection - Router receives data from the internet - It transmits the data as radio signals using an antenna - Computers wireless adapter picks up the signal and turns the radio signal into data that the computer can understand
   • Advantages of wifi - Allows inexpensive LANs to be set up without cables - Health and safety due to tiger desktop as no trailing cables - global set of standards as you can use wifi all over the world
   • Disadvantages of wifi - Wifi networks have very limited range around 150 ft - transmission speed slower than cable - There may be health problems using wifi

7. Topology

   • A physical configuration of a network and how it is linked together.

8. Remote Management

   • See which users are using the network
   • Log off users who have forgotten to do so
   • Clear printer queues at stations
   • Guide users through problems
   • Send Instant messages
   • Shut down stations

9. Software components / Network management

   • Network manager software - If you are a network manager you are responsible for a network consisting of several hundred computers, you would need help looking after all to keep the network running
     • Keeping all application software up to date - Check that the bandwidth is being used correctly - Finding out if a user have installed no licensed software without permission on a networked computer - Making sure that all computers have up to date software with the latest security patch he's so that hackers cannot get into there network
   • User accounts and logs under network management
     • Everybody who uses a network is given a user account. The user is set up by the network administrator or network manager - The network manager will allocate the user certain rights - All users can change their passwords, change desktop settings and make their own files in their storage area
   • Security strategies
     • Use of passwords and user id's used to authenticate a user of a network. Ensure that access is restricted to authorise users. - Virus checkers all computers have the latest virus checking software loaded which scans the computer and all files, email and instant messages for viruses. If viruses are detected, they can be removed.
       • Firewalls can be software, hardware or both and protect the network from hackers. - Encryption user to keep data secret when being sent over networks. Used for financial details when being send for the internet.