Test 2 Flashcards
What does ARPAnet stand for?
Advanced Research Projects agency networks
Define a LAN.
local area network, a network covering a small geographical area connecting a number of computers and shared devices.
What are the devices in a LAN connected to?
Hubs and switches which are connected to routers and/or a modem to allow the LAN to become a part of the internet/WAN
Define a WAN.
wide area network, a network that covers a large geographical area formed from a number of LAN’s joint together with the use of a router or modem.
What is the difference between a LAN and a WAN?
- area managed
- LAN is private while WAN can be private or public network
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What is a MAN?
larger than LAN but smaller than WAN covering several buildings
What are the benefits of networking computers and devices?
- users can communicate using emails and instant messaging
- devices can be shared reducing costs
- a network manager can oversee the network and restrict access to certain external networks or apply access to specific users on certain files
- users can share files and data
What are the disadvantages to networking computers?
- malware and hacking and effect the entire network
- managing a large network can be a difficult task
- devices breaking down can effect the whole network
- cabling and servers can be an expensive initial outlay
What hardware is required in networked computers?
- LAN cards
- routers
- switches
- cabling
- wireless routers
What software is required in networked computers?
- firewall operation
- security utilities
- network management and operations
What services are required in networked computers?
- DSL
- wireless protocols
- IP addressing
- satellite communication channels
What is a switch?
hardware used to connect together a number of devices to form a LAN that directs incoming data to a specific destination address only
What is a hub?
hardware used to connect a number of devices to form a LAN that directs incoming data packages to all devices on the network
What is a router?
a device which enables data packets to be routed between different networks
What is a modem?
a device that converts digital data to analogue data t be sent down a telephone wire and converts analogue back into digital data to allow the computer to process.
What is a private network?
Owned by a single company which is responsible for purchasing their own staff, equipment, software and maintaining the network (usually LAN’s with password and user ID requirements)
What is a public network?
Owned by a communications carrier company with many organizations using it meaning no user ID or password requirements
Define a WLAN?
similar to LAN without wires and cables
wireless network communications over short distances using radio or infrared signals
What are WAP’s?
allows a device to connect to a LAN without a wired connection
they are connected to the wired network at fixed locations (the more WAP’s, the more uninterrupted wireless communications)
What technology do WAP’s use?
Spread spectrum technology (wideband radio frequency with a 30 to 50 m range)
Infrared technology
What is the size in m of each network?
WAN - 100m to 1000km
LAN - 10m to 1000m
MAN - 1km to 100km
What are the 4 network topologies?
bus
star
mesh
hybrid
What is a bus network?
uses a single central cable in which all devices are connected to this cable so that data can only travel in this one direction and only one device can transmit at a time
terminators are required at each end to prevent reflection
What are the disadvantages of a bus network?
- if the main cable fails the whole network is down
- network is not secure as packets pass through every node
