Networks

Networks

1. Protocols

   • FTP
     • Is a protocol for transferring files between two computer
   • POP3
     • is a protocol for downloading email from a mail server
   • SMTP
     • is a protocol for uploading email to a mail server
   • IMAP
     • replaced POP3 when web-based email took off

2. Area Networks

   • LAN
     • A Local Area Network is a network confined to one location or organisation. Its resources are only accessible by computers on that LAN
   • WAN
     • A Wide Area Network (WAN) is a network of LANs spanning a wide area. The Internet is an example of a WAN
   • Wired
     • Computers are connected with physical wires. Electrical pulses on the wire are used to transmit binary data
   • Wireless
     • Radio waves are used to transmit binary data. No physical connection needed
   • Different of network
     • Star
       • All computers are connected to a central hub or switch. A hub sends each message to all the other computers A switch checks the address and sends it only to the correct one
     • Ring
       • Each computer is connected to two other computers in a ring formation Each computer receives signals from one of its connected computers If the data is for itself, it reads it, if not it transmits it to the next computer The data travels round the ring in one direction until it reaches its intended recipient
     • Bus Topology
       • A single cable connects all the computers All the clients and servers connect to this cable Terminators are attached to each end of the cable.
     • Mesh Topology
       • Each computer is connected to one or more other computers A full mesh has every computer connected to every other computer A partial mesh has only some of the computers connected