Computer networks and topologies Flashcards
What is a Network
Two or more computers that are connected for the purpose of communication
Advantages of Using Networks
File sharing - Users can share files with others
Hardware sharing-users can share hardware with others
Communication-Users can communicate via email etc
Roaming access -Users can access files on any computer
What are the benefits for larger organisations of Networks
Centralised maintenance+Updates - Software managers can Schedule Updates for all computers
Centralised security - Software managers can implement a fire-wall or antivirus across a network protecting user files
User Monitoring - Network managers can see what users are doings
Disadvantage of Networks
Cost - Can be costly to buy equipment needed
Management - You need special staff to manage it
Spread of Malware - Malware can easily be transferred
Hacking - Someone may access data without permisson
What is a LAN
Local area Network - geographically confined to one site A group of devices connected by a Hub or switch
What is a WAN
A Wide area network Can be used by banks with other branches etc Can be unlimited in range Each LAN is connected using the WAN
What are the factors that affect Network performance
Bandwidth
Number of Devices Connected to it
Network Latency
Type of Traffic
What is Bandwidth
The amount of Data a transmission medium can transfer over a given period of time
What is the typical Bandwidth for Twisted copper wire,Fibre optic,Home WIFI and Business WIFI
Twisted Copper Wire - Up to 10 Gigabits p/s
Fibre optic - Up to 100 Gigabits p/s
Wi-Fi - Up to 600 Megabits p/s
Business Wi-Fi - Up to 6 Gigabits p/s
If One device is allocated 50MB p/s how much will 2 devices be allocated
25 each
What is Latency and which Network type Experience more Latency Hub or switch and why
Time taken for a message to be sent to one device from another
Hub because it broadcasts messages to all devices wasting bandwidth on sending messages to unnecessary devices
What are Transmission Errors
When two devices try to communicate the same time their signals collide and they cancel each other out
What are the two models of Connecting computers over a network and how they work and give an example
Client-Server Network - A Server/Computer Manages and stores files They control the network E.G File servers web servers mail servers best suited for organisations with many computers
Peer to Peer Network - No Computer has Control over another All equal each computer is known as a peer best suited for organisations with few computers
What Hardware is Required to create a Network
A Network Interface controller (NIC) : Offers Interface Port for wired connections and Radio receiver for Wireless. Provides a Method of Connecting to the network
A Transmission media - Carries the data via cables or radio signals
Network Connection devices - allows Computers to connect
What are the 4 types of network connection devices and how they work
Hubs- Allows wired devices to connect with each other any traffic is transmitted to all devices Slowing down network performance by sending unnecessary signals + They don’t know which devices are connected
Switches- Same as Hub But knows what devices are connected And sends traffic to intended recipient only improving network performance
Wireless Access points - Uses wireless transceiver to allow wireless connections sends wireless traffic it receives onto main wired network
Router - Used to send data signals across the internet work by collecting knowledge of available routes and determines the best one. usually have a built in wap and modem (allows users to connect to the internet)
What is Hosting
The storing of files and data on a web server. The web server is referred to as the host
What is a URL
Uniform resource locator
Contains IP address and DNS of a web page
what are the 3 hierarchical levels which work in reverse order
bbc - 3rd level
co - second level
uk - Top level
What is DNS
Domain name server-The server that forwards the users request to the server address
What is the cloud
Remotely accessed storage through the internet
Benefits of the cloud
You can access files from any device
users can be granted access to get the data
What are the negatives of the cloud
No internet = no access
No guarantee someone else is not accessing data
What is mesh topology and give advantages and disadvantages give an example who would use it
2 types:
Full mesh+Partial mesh
Each node is connected usually to more than one node
and to transfer data they send data to one computer to another till it arrives
Advantages: messages will always get through because there is more than one route messages can be sent quick if route is short
Disadvantage: full meshes are impractical many connections require a lot of maintenance
Military organisations
What is Network Typologies and what 2 are the most common
The pattern or arrangement in which the computers are connected the 2 most common are:
Star topology
Mesh topology
What is star topology and give advantages+Disadvantages+what uses it
All computers connect indirectly through a switch or a hub it acts as the central point to all communications
Advantages:
One node failure doesn’t affect others new nodes can easily be added
Disadvantages:If switch fails whole network fails + Can be expensive with all those wires
Routers use it
