Networks

Networks

1. A Local Area Network (LAN) is a network confined to one location or organisation Its resources are only accessible by computers on that LAN.

   • advantages of LAN are: Software program sharing, Sharing of the internet and Securing of data.
   • disadvantages of LAN are Setting up a LAN is expensive, Limitation of distance and Server crashes affect all computers.

2. A Wide Area Network (WAN) is a network of LANs spanning a wide area The Internet is an example of a WAN.

   • Advantages of WAN are: Increases bandwidth, Boosts your privacy and Cuts costs, increase profits.
   • disadvanteges of WAN are: High setup costs, Maintenance Issue and Security Concerns.

3. Topologies

   • BUS: 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.
   • 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.
   • 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.
   • MESH: 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.

4. POP3 and STMP

   • pop3- protocal for downloading an email
   • uploading an email

5. TCP/IP

   • Application layer- provides applications services to users and programs.
   • Transport layer- handles data consistency functions (error checking)
   • Network-provides network addversing and routing(IP address)
   • Data link-Prepares and corrects data to be passed to the physical layer.
   • physical layer-Transmits and receives bits.