Hardware Flashcards
What is a Network Interface Card (NIC)?
An electronic chip built into the motherboard of the device. It is hard-wired with a unique ‘address’, called a MAC address
True or False? No two MAC addresses are the same
True
What jobs does the NIC do?
Holds the MAC address
Responsible for converting data on the computer into the format used by the network
What is a network protocol?
A set of rules for a network
What is a hub?
Is a piece of hardware used to connect computers on the same network together
How do devices connect to a hub?
Every device gets plugged into the hub via cables
What is a packet?
A unit of data made into a single package that travels along a given network path
What happens when a hub receives a data packet?
It immediately copies it and broadcasts it to all connected devices
What does every packet contain?
A destination address
What is the main disadvantage with hubs?
They are inefficient, due to data being sent to every computer, even if only 1 needs it
What is a data collision?
When two or more computers want to place a data packet on to the network at exactly the same time
What happens if a data collision happens?
The collided data is marked as unusable and the two computers are forced to send their data packets again, at slightly different times
What are the 3 disadvantages with hubs?
Inefficient
Data Collisions
Security
Why is security a big problem when using hubs?
When a hub receives data it will forward it to every device it connects to, regardless of whether the data was only meant to be sent to just one. This means that there is the potential for any computer connected to the hub to read data that was not intended for it
What is a switch?
A switch is similar to a hub in that that allows computers to be linked together and exchange data, but unlike a hub, it does not broadcast every data packet to every device which means there is improved security
How do switches help speed up the running of the network?
By reducing the impact of data collisions
What does a switch contain?
A number of ports and it stores the MAC addresses of all devices that are directly or indirectly connected to each port
What happens when a data packet reaches a switch?
It’s destination (MAC) address is examined and a direct connection is made between the two machines
Which is more expensive, a switch or a hub?
Switch
Compare how a hub and a switch connects nodes together
A hub connects nodes on the network together, but is not intelligent
A switch is an intelligent device which connects nodes on the network together
Compare how a hub and a switch transmit data packets
In a hub, data packets are transmitted to every node connected to the network
In a switch, data packets are transmitted only to the node for which it was intended to
Compare data collisions on a hub and a switch
A hub has a higher risk of data collisions, leading to slower network performance
A switch has less of a risk of data collisions leading to improved network performance
Compare the security of hubs and switch’s
In a hub, there is a security risk, due to data being sent to all nodes
In a switch, has better security due to data only being sent to the correct node
Compare the cost of a hub and a switch
Hubs are less expensive than a switch
What is a router?
A device that transfers data packets, by the most efficient route, from one network to another
What does a router do when a data packet arrives?
Reads the data packet’s destination address
Looks up all the paths it has available to get to that address
Checks on how busy each path is at the moment
Sends the packet along the least congested (fastest) path
What 2 other tasks can routers perform?
Exchange protocol information across networks
Filter traffic
What is an ethernet cable made up of?
A set of four ‘twisted pair’ copper wires enclosed in a plastic sleeve with a standard network plug on the end
What are fibre optic cables made up of?
Many glass fibres held together inside a sheath
What is a WAP?
Wireless Access Point
Why do you need a WAP?
To connect Wi-Fi devices to a wired network
Where does the cable from a WAP connect to?
A hub or switch
How is a WAP similar to a hub?
It does not read the destination MAC address of a data packet and so the data is broadcast to everyone connected to it
Give some examples of transmission media
Ethernet cables
Fibre optic cables
Wi-Fi
