Networks Flashcards
What is a network?
An arrangement of computers and other devices connected together to share resources and data
What does LAN stand for?
local area network
What are 3 characteristics of LAN?
- A network that covers a relatively small geographical area
- owned by the organization that uses it
- managed by a local manager or a team on that site
Give 3 examples of where LAN is used
1) Home
2) Hospital
3) Factory
What does WLAN stand for?
wireless local area network
What is WLAN?
like a LAN but wireless, all connects to a router
What does WAN stand for?
wide area network
What are 3 characteristics WAN?
- it covers a wide geographical area by connecting two or more LANs
- computers in a WAN can connect with computers and users in other locations
- managed by several different people or parts of an organization working together
What is the largest WAN?
the internet
What is a client-server network?
A network that has at least one server to provide services to the client computers
What is are 3 characteristics of a peer-to-peer network?
- doesn’t have a centralized server
- all computers are equal and communicate with each other directly without having to go through a server
- each user can give other users access to their computer and their programs and to any other device connected to them
What is a network topology?
how the devices on a network are connected to each other
What is a BUS TOPOLOGY?
A bus network consists of a single cable which each workstation is connected
Name 2 advantages of bus topology
1) cheap to install and set up
2) easy to add new devices
Name 2 disadvantages of bus topology
1) if the main cable fails, the whole network will fail
2) lots of data collisions if two or more devices transmit at the same time (lower data transmission speeds)
What is a RING TOPOLOGY?
Cable connects one network device to connect another in a closed ring
Name 2 advantages of ring topology
1) no collisions because of the use of the token system
2) data transmission is simple as data only travels in one direction
Name 2 disadvantages of ring topology
1) slow transmission speeds, as data must pass through each computer before arriving to the destination
2) if the cable breaks then there will be no data transmission
What is a STAR TOPOLOGY?
each workstation is connected to a central point
Name 2 advantages of star topology
1) A damaged cable will not stop the whole network
2) Easy to locate faults
Name 2 disadvantages of star topology
1) If the hub fails, the whole network fails
2) Expensive to install
What are 2 advantages of connecting computer to form a network?
- The users can share resources
- files can be shared along a network allowing users to work collaboratively
What are the benefits of a peer-to-peer network on a small company?
- expensive server and network operating systems are not required, so it is cheaper
- specialist staff are not needed to administer and maintain the network, so it is a lot cheaper
- requires less specialist knowledge to set up
What are the benefits of a client-server network on a large company?
- all data can be saved on a file server, so it can all be backed up at the same time without having to back up the data on each computer seperately
- network security is stronger as access to file servers are controlled using logins and passwords
What is the range of frequencies commonly used for data transmissions in wireless networks?
2.4-5 GHz
What is meant by a channel?
each frequency range is divided into separate channels
What is bandwidth?
Amount of data that can be transmitted per second (measured in bps)
What is the bandwidth of a cable network?
10 Gbps
What is the bandwidth of a wireless network?
600 Mbps
What is the role of network interface controllers in connecting devices to computer networks?
- formats data so that it can be transmitted and received across a network
- NICs are often built on chips on the computer motherboard
What does the MAC address do?
ensures that data is directed to the correct computer
What are hubs and switches used for?
-used to link computers so that they can communicate with each other once they have connected to the network using the NIC
What do routers do?
- connect different networks together
- read address information and forward the messages to the correct network
- transfers data between home network and the internet
Why are switches better than hubs?
- switches read the destination addresses of the messages and relay them to only the intended recipient
- this reduces network traffic
Why is data split into packets?
Data is split into packets so that higher bandwidth isn’t needed for larger files
What are 3 components that a packet consists of?
- header
- body
- footer
What does the header component do?
- contain the source and destination address
- checks how many packets the data has been split into
What does the body component do?
contains some of the data of a file
What does the footer component do?
the footer informs the receiving device that this is the end of the packet
What is a checksum?
an error detection technique
What is flow control?
allowing the receiving computer to tell the sending computer to slow down transmission, so the receiving computer has time to process the received data
How are devices connected on a wireless network?
- radio waves connect devices on a wireless network
- each device has an adapter that sends and receives radio signals
- a router broadcasts a signal that devices can detect and ‘tune’ into.
what are 4 fields in a network packet
- source
- destination
- sequence number
- packet length
