Networks and Communications

Types of Network
1. Wide Area Network (WAN)
  1. Covers a large geographical area e.g internet
2. Local Area Network (LAN)
  1. Covers a small area e.g. school, home, etc.
3. Cabling can be expensive, large network managing is complicated, if file server breaks down the servers become inaccessible, viruses can spread, danger of hacking.
4. Sharing devices saves money, easy file sharing, easy (instant) communication, easy backing up data on file server
Internet
1. An international network of computers.
  1. WWW is only part of the internet. Other parts include: email, instant messaging and file sharing.
  2. Types
    1. Dial Up
    2. Cable modem
    3. Leased line ; A connection that has been paid for by a company, only they can use it and it is a permanent connection between two distinct places.
    4. ISDN - Integrated Service Digital Network ; Uses digital transmission and can transfer data and voice at the same time. Faster than dial-up.
    5. ADSL - Asynchronous Digital Subscriber Line ; faster than dial-up connection, uses telephone lines.
Emails
1. Spam, phishing (scams), viruses can easily spread through attachments, recipient needs access to internet, no guarantee that email will be read.
2. Fast delivery, can be sent whenever, cheap, can be sent to one or several people at once.
Definition
1. A number of computers linked together to allow them to share resources. Networked computers can share hardware, software and data.
Network Topologies
1. Bus Network
  1. Easy to install, cheap
  2. If main cable fails, the whole system will too. Slow. Security at risk.
2. Star Network
  1. expensive (cable), extra hardware (hubs/switches) required, if hub/switch fails all devices will have no connection.
  2. Reliable, high performance, no data collisions
3. Ring Network
  1. Quick, no data collisions.
  2. If main cable fails, the whole network will too.

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Networks and Communications

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	Created by maryamxjay over 10 years ago