Networks

Networks

1. consists of a number of computers and hardware that are linked

2. internet

   • a collection of inter-connected computer networks
   • need a router and a modem to connect to the internet#
     • modem stands for modulator/demodulator
       • converts digital signals to analogue signals used by telephone lines
   • set of rules = protocol
   • TCP = transmission control protocol
   • IP = internet protocol
   • every device connected to the internet has an IP adress
   • IP addresses change where as MAC addresses don't
   • HTTP = Hypertext Transfer Protocol
     • HTTPS = Hypertext Transfer Protocol Secure

3. network topoligies

   • LAN = Local Area Network
     • single area
     • share resources
     • data easily backed up
     • expensive
     • complicated to manage
     • one virus can affect multiple computers
   • WAN = Wide Area Network
     • All over the world
   • Bus
     • one long line
       • if line breaks anythng behind the beak won't work
     • cheap
     • new nodes can easliy be added
       • Node = router
   • ring
     • in a circle
       • if line breaks nothing will work
     • not affetcted by network traffic
     • more pc's can be added without the loss of preformance
   • star
     • server connected to switch hub pc's connected to switch hub
     • advantages
       • if one cable fails all other PCs will not be affected
       • fast data transfer with no collisions
     • disadvantages
       • expensive
       • if centeral device fails everything goes down

4. security

   • physical security
     • S.A.D.F.L.A.B.
       • Avoid Ground Floor
       • Alarms
       • Serial Number
       • Fire Alarms
       • Lock Windows
       • Doors (Locked)
       • Blinds
   • Preventitive
     • Passwords
     • Fire Walls
     • Access Rights
     • Encryption
     • Acceptable Use Policies
   • Corrective
     • Redundant Hardware
     • Backup/Restore Procedures
     • Recovery Procedures
   • Detective
     • Firewall Software
     • Fire Alarms
     • Virus Checking Software
     • Audit Trails