Unit 3 - Networks and Protocols Flashcards
What is the internet?
A worldwide collection of interconnected computer networks.
What is a WAN?
A Wide Area Network covers a large geographical area that connects LANs.
Infrastructure between the LANs is hired from telecommunication companies who own and manage it.
What is the biggest example of a WAN?
The Internet
What is a LAN?
A Local Area Network covers a small geographical area on a single site.
All the hardware for the LAN is owned by the organisation using it.
What are LANs wired with?
LANs are wired with transmission medias such as:
. UTP ( Unprotected Twisted Pair) cable
. Fibre Optic cables.
. Wireless using routers and Wi-Fi access points.
How are WANs connected?
WANs are connected with transmission medias such as:
. Telephone lines
. Fibre Optic cables
. Satellite links
What is an IP adress?
An Internet Protocol address is a unique string of numbers separated by full stops and is used to identify each computer using IP to communicate via a network.
It also also used to identify where data packets need to be sent and where they have come from.
What are the 2 different versions of IP addressing?
IPv4 (4.3 billion addresses only) and IPv6 (a lot)
What is a circuit switching network?
. Circuit switching lets you send digital messages across a network by setting up a physical path between the sender and receiver.
. This is done using wires or fibre optic cable and is set up prior to transmission of the message.
What is packet switching?
Packet switching is breaking data into packets (Each data packet would contain the same number of bytes.), sending them across the Internet to another computer, and then reassembling the data and error-checking it.
What happens if there are any lost or corrupt packets?
The recipient’s computer would acknowledge what had happened and packets would automatically be resent after a set time interval.
What is a router?
A router sends data between networks along the path that is least busy at that moment. It is required to connect a LAN to a WAN.
What is a DNS?
A Domain Name System or server takes a domain name from the user such as ‘www.bbc.co.uk’ and translates it to an IP address and then directs it into the requested website
What is a URL?
. A Uniform Resource locator is used to specify the means of accessing a resource across a network and its location.
. The protocol and the domain name of the resource together form the URL.
Why do IP Addresses sometimes change?
An IP address can be static or dynamic
. When a device is assigned a static IP address, the address does not change every time it connects to a network.
. Most devices use dynamic IP addresses, which are assigned by the network when they connect and change over time.
What is a NIC?
A Network interface card is hardware that connects a computer to a
network.
It can be wired or wireless
What is a MAC address?
. A MAC (Media Access Control) address is a unique identifier given to devices which communicate over a local area network (LAN)
. MAC addresses are static, they can never change
. It is assigned to an NIC
. Made up of hexadecimal.
How many bytes are there in a MAC address?
6 Bytes (48 bits)
What is a router?
A router sends data between networks. It is needed to connect a local area network to a wide area network.
It uses the IP address on a device to route traffic to other routers.
Sends data packets on their way in the best direction.
What is a switch?
A switch sends data between computers on a local area network. It uses the MAC address in the NIC on a device to route traffic.
Reduces network traffic and increases speed.
What is a hub?
A hub is a small device that allows wired devices to connect to a network.
What are the 4 types of network connection devices?
. Hub
. Switches
. Wireless Access Point
. Routers
What are the advantages of networking?
. Sharing resources such as printers save money
. You can access your files from any computer in the network.
. Data is easy to back up as it is stored centrally on the server.
What are the disadvantages of networking?
. Purchasing the network hardware is expensive.
. Managing a large network is difficult.
. Viruses may be able to infiltrate the network and infect every computer.
What are the two different ways a LAN can be set up?
. Star
. Mesh
What are the advantages of a star network?
. Fast data transfer as there are fewer data collisions.
. If one cable fails, the other workstations are not affected.
What are the disadvantages of a star network?
. Requires additional hardware such as the central switch
. If the central device fails, the whole network goes down.
What are the advantages of a mesh network?
. No single point of failure, it is a self healing network
. Expansion and modification can be done without disrupting the network.
. Data can be transmitted from different devices simultaneously
What are the disadvantages of a mesh network?
. Can involve unnecessary connections
. Expensive to install cabling if doing wired connections
. Network maintenance and administration is difficult.
What is an ethernet?
. A standard for networking local area networks using protocols
. Frames are used to transmit data.
. Uses twisted pair and fibre optic cables.
. A switch is used to connect computers.
What is a virtual network?
A virtual network is a network that can securely connect geographically unrelated computers via the internet.
. Requires no direct physical connection but allows file sharing and communication.
How is wireless transmission used?
Commonly uses radio waves to communicate
Susceptible to interference from objects and other nearby electronic or radio devices.
What is a WAP?
A Wireless Access Point is hardware that allows a Wi-Fi-enabled device to connect to a network.
What are the risks of wireless networking?
Criminal activity - Could bypass the firewall and plant viruses
Bandwidth stealing - Using the network to download anything. It causes the network to be slow.
Confidentiality - If not encrypted, an intruder can gain access to confidential information.
What is Bluetooth?
A method of exchanging data wirelessly over short distances – much shorter than Wi-Fi. Examples of typical Bluetooth use could be, headphones, car mobiles etc.
What is encryption?
Encoding readable data (plain text) into unreadable data (ciphertext). Only the intended recipient can decode the data using a special key. Protects sensitive communications against hacking.
What is the key in encryption?
A sequence of numbers used to encrypt or decrypt, often data using a mathematical formula.
What is private key (symmetric encryption)?
A single key used to encrypt and decrypt the message. It must be given to the recipient to decrypt it. The Caesar shift was the earliest form of this.
What is public key (asymmetric encryption)?
Two keys are used. One to encrypt and one to decrypt. This one is much more secure as it means you dont have to send or reveal your key.
