1.3.3 Networks Pt1 Flashcards
Network
Two or more devices connected together with the ability to transfer data between each other
Network advantages
Allow for collaboration
Access information quicker
Allows for sharing resources
Allows streaming
Network disadvantages
Relies on connectivity/internet access
We can become dependent
Expensive to maintain
LAN
Local Area Network
A network where devices are geographically close to each other
WAN
Wide Area Network
A network where devices are connected across a large geographical area
MAN
Metropolitan Area Network
A network across one metropolitan area such as a city
PAN
Personal Area Network
A network centred around one person’s workspace with connected devices
SAN
Storage Area Network
A network dedicated to sharing data across devices
WPAN
Wireless Personal Area Network
A personal network which is not connected by wires
VPN
Virtual Private Network
A network which allows users to access a private network from another location
Coaxial copper cables
Single copper cables that need to be replaced from time to time as the insulation may degrade
Unshielded Twisted Pair (UTP)
Two copper cables twisted around each other
Shielded Twisted Pair
Two copper cables twisted around each other with metal shielding to reduce interference
Copper wire advantages
Cheap to install, can directly power telephones
Copper wire disadvantages
Lower bandwidth, short lifetime
Fibre-optic cables
Glass cables that use total internal reflection to transmit light signals
Fibre optic cables advantages
Long lifetime, less electromagnetic interference, higher bandwidth
Fibre optic cable disadvantages
Expensive to install
Bus topology
A single backbone cable with passive nodes attached, there are two terminators at either end. Packets are sent to all nodes
Bus Topology Advantages and Disadvantages
+ easy and cheap
- slow, less secure, if the main cable fails it all fails
Ring Topology
All devices are connected in a closed loop, packets go in one direction through each device. A receiver sends an acknowledgment to the sender when a packet is received
Ring Topology Advantages and Disadvantages
+ less data collisions
- if one cable fails the whole network fails, less secure, hard to add new nodes
Star Topology
Used in LAN networks, each device is connected to a hub by a cable
Star Topology Advantages and Disadvantages
+ Fast, a cable failing only impacts the data through it
- expensive to install, the central hub failing fails the whole network
Full Mesh Topology
All devices are connected to each other and can send messages directly
Partial Mesh Topology
A device is connected to all other devices but some devices may be connected in a different topology
Mesh Topology Advantages and Disadvantages
+ fast, data is re-routed if a cable breaks “self healing”
- expensive, difficult to maintain, impractical for wired networks
Network Interface Card (NIC)
Converts data signals from a device to ones that can be transferred across a network
Router
Forwards data packets between computer networks
Works by inspecting the destination IP address of the packet, changing the source MAC address to be its and the destination to be that of the next router
Gateway
Connects two networks that use different protocols
Modem
Converts data from digital formats into electrical signals
Hub
Broadcasts data from a device to all devices on its network
Switches
Filter data packets and forward to a specific device
Bridge
Connects two separate LAN networks together
Wireless Access Point
A network hardware that allows wireless-specific devices to connect to a wired network
Physical Topology
Defines how the devices are physically connected
Logical Topology
Defines how the devices communicate across the physical topologies
SSID
A 32-character locally unique code that identifies a network in Wi-Fi
WPA2
A protocol that encrypts data and ensures security on Wi-Fi networks
DHCP
Dynamic Host Control Protocol
A protocol that allocates locally unique IP addresses to devices as they connect to a network
VoIP
A protocol that allows us to make voice calls over the internet
