Networks

Networks

1. LAN

   • Local Area Network is a network confined to one location or organisation
     • Only allowed to be used by people within the LAN

2. WAN

   • A Wide Area Network is a network of LANs spanning a wide area
     • The internet is an example

3. Disadvantages

   • Expensive - extra hardware needed
   • More room for error - uf something goes wrong, every other computer gets affected
   • Difficult – it requires a lot of technical expertise

4. Topologies

   • Bus
   • Ring
   • Star
   • Mesh
     • Circuit switching
       • If something is using it, a route is blocked so you have to switch packages onto different lanes
     • Packet switching
       • Packets will take different routes to its destination even though they take different paths, they get there at the same time in order to be reassembled
     • Pathfinding
       • each path is assigned a wight which is relative to the connection. an algorithm will find which is the least 'weight' and therefore the best path

5. Advantages

   • Share files, so the same files are available whichever computer you use
   • Share resources such as printers and Internet connection.

6. Protocols

   • Standard Protocols
     • Standard protocols are well known protocols that are used by a wide variety of applications.
   • HTTP and HTTPS
     • They are the standard protocol used for requesting an HTML file from a webserver
     • HTTPS is encrypted therefore safer
   • FTP
     • It is commonly used by web developers for uploading their HTML files to their webservers
   • POP3 and SMTP
     • POP3 is a protocol for downloading email from a mail server.
     • SMTP is the protocol for uploading email to a mail server.
     • Emails are sent with SMTP and received with POP3
   • IMAP
     • Allows email to be left on the server, and read from different mail readers.

7. IP Addresses

   • IP (Internet Protocol) addresses are the unique identifiers assigned to computers on a TCP/IP network (including the Internet)
   • IPv4 has 4 billion unique addresses
   • IPv6 has 340000000000000000000000000000000000000 unique addresses (more than the number of atoms in the universe)