OCR Computing Chapter 6
- Created by: AliceSarah
- Created on: 06-06-17 21:58
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- Ch. 6 - Networking
- LAN
- Convenient data sharing, easy to back up, update and monitor computer use. users can easily communicate
- Expensive to maintain, specialist staff needed, viruses spread quickly, data easily hacked
- WAN
- Widely available, convenient data sharing, communication & development is easy
- Harder to set up, private WANs expensive, can be slower than LANs
- Hardware
- Cables - Fibre optic cheaper & faster
- NICs - make and recieve electrical signals, every device needs one, simple MAC addressing
- Hubs connect devices. Transmit signals to all deivces
- Switches - connect hubs/ networks together. Only send messages to intended devices
- Routers connect computers to the Internet
- Topologies
- Ring - very fast, BUT vulnerable, backbone problems bring it down
- Bus - easy to set up, cheap, BUT back bone issues bring it down
- Star - robust, faster than bus BUT harder to maintain, expensive to set up
- Types
- Client Server - very common, good computers, serve many other computers. Efficient & high speed
- Peer to Peer - all computers are equal, servers & clients. Easy to set up, hard to maintain, poor security, slow bc multi tasking
- Protocols
- TCP - connection of hosts (remote computers)
- IP - packet (data bundle) construction - check it has length, data, correct address
- Packet switching - packets take diff. routes, saves time, decongestion
- HTTP distributes webpages
- I/P address every computer has one, can change
- MAC address Unique hex no. in the NIC
- Internet
- Biggest WAN - connects millions of computers - no owner
- www uses internet to share HTML pages
- Hardware: Modem converts phone to digital signals, router connects networks together or connects computer to ISP
- HTML used to run webpages, & CSS
- Security
- Easy access = data loss, theft of data, malware, system damage
- Failover - if danger is detected, the system shifts to a different system
- Authentication user ID & password
- Backups - store data off site (cloud)
- Archives data that is no longer in use. Kept for legal reasons
- Disaster recovery, prevention, backups, plan for loss
- Acceptable Use Policy - what users can/can't do
- File Standards
- JPG, MPEG - lossy
- GIF, MP3 PDF -lossless
- Compression
- Lossy - removes some data, can't be recovered
- Lossless - allows file to be reconstructed, removes repeated data
- LAN
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